Mustang II Suspension Question

[TBART70]

I have an after market Martz chassis for my 70 Camaro (should have bought a different one) with mustang suspension, the lower control arm is 15" from bolt center to middle of the ball joint. My question is if I replaced the control arm with one that is 15 3/4" long and move the inner bolt hole in 3/4" how much of a difference will there be in geometry. I found a real nice control arm from TCP (chris alston) that I would like to utilize because some of the features of my chassis is not that great. Any help would be greatly appreciated. Also does anybody know how I can figure out the total geometry on this thing? Also would like to put ATS spindles on it. Mostly purchased it for the WOW factor it is only a street car no racing intended. Most people at the cruise nights won't even know that it isn't the best suspension but it looks cool. As long as it handles as good as stock or at least a little better I will be happy, but I figured if I could improve a little I will.

[sinned]

Mustang II front clips are street rod parts, not designed for hard core handling. You would need to redesign the entire front end to get any real handling out of it. Figuring out the end numbers is the easy part, taking all the nesessary measurements is the hard part.

[RobM]

every one says that but i never hear what is actualy wrong with them... I have yet to blue print one out. what are the major down falls of the mustang II? they are prety easy to fabricate and it would be cool if i could work the bugs out and give it a try in my car.

[TBART70]

I am a newby on suspension dynamics still learning, I know that there are some people on here that know their stuff. Have spent many hours reading their posts. The problem with my chassis is that it was flimsy, it added some supports to it, seems to have helped alot. The mustang suspension on the other hand many have said it is less than desirable. That's why I would like to make some minor improvements. Also learn the pro's and con's of it.

[sinned]

every one says that but i never hear what is actualy wrong with them... I have yet to blue print one out. what are the major down falls of the mustang II? they are prety easy to fabricate and it would be cool if i could work the bugs out and give it a try in my car.Control arms are way too short resulting in drastic lateral RC migration as well as excessive scrub radius.

[parsonsj]

Dennis has it. Here's some more thoughts (http://popularhotrodding.com/tech/0505phr_susp/) on the MII suspension as sold by AME.

jp

[red65FB]

Hi - Newbie here. While I understand the negatives of the MII suspension, I believe that there are enough people running MII's that would like to improve them. Until now, the only advice I have seen is "start over". There must be something that can be done in the world of bolt-on's that would improve the existing geometry.

To add to TBART70's suggestion, I myself would appreciate some ideas to improve what I have.

AT

[alcino]

Works for me. But my car was designed for it:rotfl:

[sinned]

Hi - Newbie here. While I understand the negatives of the MII suspension, I believe that there are enough people running MII's that would like to improve them. Until now, the only advice I have seen is "start over". There must be something that can be done in the world of bolt-on's that would improve the existing geometry.

To add to TBART70's suggestion, I myself would appreciate some ideas to improve what I have.

AT
No, there is nothing that can be done to improve the geometry other than to start over. It doesn't matter if throw a million dollars at it, without throwing the control arms in the garbage and starting from scratch it a junk street rod design (or in Al’s case as kick ass OE design that works well ONLY on factory Mustang II chassis').

[TBART70]

I looked at pictures of II Much unbeleivable car.
He said his lower control arms were in the 13 in. range and went to 15.6 in. Mine are 15 in. now and I want to go to 15 3/4 in. I do not know what the uppers are I have to measure. As long as my suspension is durable and reliable I will be happy. If it handles good that would be a plus. I will have a 17x9.5 wheel with a 5 in. backspace with a 275/40/17 tire on the front. I don't know what these demensions will do for scrub radius, camber gain or RC migration ( had to look up definitions on them):dunno: but hope before the car hits the road in a few years I will understand them better.

[red65FB]

Alcino - love your car. Great write-up in PHR. What's different in your set-up vs. a bone stock MII? TBART70 mentioned longer LCA's. Are these fabricated? My car is a 65 Mustang FB with an old school factory MII cross-member transplant - not a kit. Apart from the obvious differences in wheelbase, and frame construction, I don't see why changes that worked for you wouldn't offer improvement in my application.

Any word on wether or not AFX's planned MII spindles will improve geometry?

AT

[RobM]

is that scrub radius caused but the factory setup or droped spindles?

[sinned]

As I recall Al’s control arms are the stock pieces it came with, or at least the stock dimensions. The reason it works on his car is because it was designed to work as a package with the entire chassis. That is the biggest problem with today’s incoming group of PTers, looking for the easy way out. You cannot simply throw some parts at a frame and expect it to work. Engineers spend hundreds of hours designing suspension systems as they are quite intricate and are definitely one of the "do it right or die" systems; kind of like brakes. If you don't know what you are doing, it is best to seek the assistance of someone who does to aid in the design/construction of what you are doing. I have over 8 months of design, and redesign, and redesign and hundreds of dollars spent on "wall art" trying to make everything work properly. It's just not as easy as you all would like it to be.

No, you cannot make Mustang II parts work on another chassis and expect it to handle well enough to run with any of the more advanced groups on a road course. Sure it will drive and turn on the street but handle well, not likely. Even in Al’s case his car could handle better with some redesign work on the UCA/LCA length and pick-ups. I realize it ran .99g on the skid and does well on the road events. It also weighs half of most the cars out there and runs R compound tires.

The scrub radius concern comes in as the control arms are so short that you need a very short backspacing to get the fitment right.

[red65FB]

As much as I would love to start over again, I bought this car pre-modded, prior to my doing enough research to know what I should be really looking for. I come from tracking a modded C5 and a Miata previously - those were great handling cars, so I'm not expecting miracles, nor am I trying to shortcut the right way to do things. I will say that for what it is, the car handles high speed canyon runs quite well with more stability than I thought possible - on street tires.

Your right - R-compounds and stiff springs will make just about anything stick like glue, a band-aid if you will. In the meantime, until I win the lottery, I plan to squeeze as much as I can out of the car as it is. I'm holding out some hope for the rumoured AFX MII spindle...:hammer:

[alcino]

sorry if i ryled things up here.


What's different in your set-up vs. a bone stock MII?


Only the rubber bushings replaced with the poly ones. Everything else is factory, but the alignment settings.(-1.75d camber, 3.5d caster, 0.5inch toe out)

I agree with dennis about the wandering RC from the short arms, or so I think. When I'm hauling ass on the road course it can be really scary during transitions when the weight is being shifted from one side to the other. I don't know how to explain it other than the car starts to feel unpredictable and I say "oh *****!" in my head. Is that the RC moving dennis?

I also agree that there is room to improve. In the future I would like to get wheels with the most backspacing possible in the front, with taller dropped spindles(AFX?) or taller balljoints and making long control arms to fit. I'm hoping to get close to 3 more inches on the control arms.

Dennis do you still have that suspension program? Could I give you some dimensions on my ideas and see how they would turn out?

[Norm Peterson]

0.5inch toe outhalf an INCH . . . :eek:

(BTW, The same bits worked fairly well on the Pinto, with no evil traits that I ever found.)

Norm

[sinned]

Yeah, I have WinGeo. Send my the numbers and I'll run them.

[red65FB]

sorry if i ryled things up here.


Only the rubber bushings replaced with the poly ones. Everything else is factory, but the alignment settings.(-1.75d camber, 3.5d caster, 0.5inch toe out)

I agree with dennis about the wandering RC from the short arms, or so I think. When I'm hauling ass on the road course it can be really scary during transitions when the weight is being shifted from one side to the other. I don't know how to explain it other than the car starts to feel unpredictable and I say "oh *****!" in my head. Is that the RC moving dennis?






I'm running similar alignment numbers, except for that toe out thingy. I wonder if this could be causing some of your transitional instability at higher road coarse speeds? You could be exagerrating the RC problem. Also, I noticed the rear of your car is very tall, this might also be adding to that sensation. I'm no expert, but screwing around with my rear ride height has resulted in improvements at the wheel and SOTP.

I too have been thinking about some of the solutions your thinking of. I'm running 4.5 BS on 17x8 rims - there seems to be room for moving the LCA and balljoint outward. Coupled with maybe a larger rim diameter to clear everything?

[RobM]

that toe out give you better ackermen right?

[baz67]

I would think no. Ackermen is a determained by the steering geometry. It does not matter what the toe is set at to the geomtry.

[alcino]

Toe out definitely helps Ackerman. My car is set up for the tight turns of an autoX track hence my use of lots of toe out. I think it causes the car to wander in the straights, but stick better in the turns. I've never changed the alignment for the road course, but maybe next time I will adjust it to see if it helps the handling. What kind of toe should I shoot for? None?

[RobM]

i would slowely dial it in untill the problem gets fixed. and the reason toe out gives more ackermen is because it causes the inside tire to stear into the corner more then the outer, more so then if you had a toe in this is a pretty comon trick in auto X and roundy round racing. I love your car man alot of people think throwing money for shiney parts solves the problem when in reality its all in the tuning! this is turning into a good thread

[Norm Peterson]

I think if you've got any more than about 50% Ackermann correction in that 94.5" wheelbase / 55" track width car, half an inch of total toe is more than you need for a 30' radius turn (per a little spreadsheet I threw together, guessing at that value as being representative of the tighter turn radii in auto-x).

Larger radius turns need less total toe to compensate for partial Ackermann correction. That's ignoring for the moment the notion that having or simulating full Ackermann correction may actually not be the hot tip, as a more complete expression for getting the wheels effectively pointed in consistent directions includes the different slip angles experienced by the inner vs outer tires (so it's somewhat wheel/tire sensitive). A greater slip angle on the outer tire than on the inner also simulates Ackermann - though a badly cambered inner wheel might yield an overall effect of anti-Ackermann. IOW, this is something best left for a test 'n' tune session or two.

Norm

[red65FB]

Toe out would cause the straight line wander. The two wheels pointing away from the vehicle's centerline fight each other as they try to head off in opposing directions. Nice for auto-x as it helps turn-in at low speeds. I find that roadcourse work needs a compromise between stability and cornering - I personally prefer stability as the speeds tend to be higher and I like driving home in one piece...

[TBART70]

Stop your making my brain hurt.:hand:

[bret]

Actually a properly set up Mustang II suspension can handle very nicely. We have installed several dozen, most notably under a 2001 Sport Trac and a 56 F100. Both of these under powered, front heavy, top heavy, under sway barred,[sp?] cheap shocked, over wheel and tired trucks drove, stopped and cornered beautifully. Tracked nicely, cornered flat, even tire temps, predictable, transitioned well...all that kind of stuff we spend hours chasing on paper. In the case of the Sport Trac the head test driver for Ford, Kevin Markham, had the truck on the track at the Ford Proving Grounds at speeds of over 120mph. His largest criticism was that it was way too neutral for a civilian...Ford would have to make it understeer a bit more for the general public. He also said it needed a little larger front sway bar [it had none] and the power steering effort was too low [it certainly was.] The Sport Trac had a 3 link and panhard bar on the rear.
On the 56 F100, Boris Said liked it so much he has asked us to build him one. This truck has a plain old Fatman's MII system with AutoZone shocks on the front and a parrallel 4 link and panhard bar on the rear.
BTW...both trucks had/have air suspension. The Sport Trac had ShockWaves all around, the F100 has airsprings front and rear.
I think the trick with any suspension, including the MII, is to drive the thing at its intended, designed ride height. So many people, especially with an air suspension, insist on driving the vehicle way too low. In addition to a terrible ride quality, the handling performance suffers greatly because the lower control arm is way past level so the camber curve goes to hell a lot quicker, the sway bar is typically not at its optimum operating level, and the bumpsteer geometry is into an unfavorable position. As with any suspension, proper load capacity and spring rate springs [air or otherwise], proper shocks, and proper installation will give you great performance.
I have not evaluated the MII suspension on paper for roll center, ackerman, etc. By the time I learned how to do all that stuff on paper I had successfully installed enough of them not to care what the calculations said. I would love for someone to run some numbers on this suspension so we could all learn why it performs as well as it does. If I get half a chance I'll do that one of these days!
I'm not sure where the MII got its bad reputation...possibly from its donor car, which was no jewel as a whole. The front suspension was definately the best part of that car.
Given the fact that there is an abundance of easily adaptable aftermarket MII systems out there that can be easily upgraded with larger brakes and better shocks, it is one of the better choices for many vehicles. The oem Mustang components are weak, hard to adapt, and should be avoided.
There are theroretically better suspension systems out there, at least on paper, but if I was building a car from scratch that had to perform with a minimum of hassle...I'd have a MII based system.

[sinned]

I would love for someone to run some numbers on this suspension so we could all learn why it performs as well as it does. If I get half a chance I'll do that one of these days! I'm not sure where the MII got its bad reputation...possibly from its donor car, which was no jewel as a whole. The front suspension was definately the best part of that car. OK, I really don't want to start an argument but you are full of siht. The Mustang II suspension is not a great handling suspension, hell one of A/M's (the pioneer of the Mustang II clip being used as a donor suspension) chief engineers for many years will admit to that. I get the sneaking suspicion that we are going to find out very soon that "bret" is actually a chassis builder and uses....Mustang II suspension (I use chassis builder very loosely as there are very few these days who actually know what they are doing).

There are theroretically better suspension systems out there, at least on paper, but if I was building a car from scratch that had to perform with a minimum of hassle...I'd have a MII based system.OK, you go right ahead. I guess since all the other designs are just "theoretically" better that would explain why NOBODY who intends use their car even for limited track uses them and runs like hell away from Mustang II designed kits. Please, bring tech or keep your rants about how great your cars drive to your street rod buddies that believe it. There are more engineers in this place and dozens of regulars at the track, wrong crowd to try and sell crap to. I’m sure Boris Said was being polite and evaluating the car as he saw it to be intended to be used, as a cruiser. OK, the tech is gone, I'm done

[silver69camaro]

[COLOR=black] The Mustang II suspension is not a great handling suspension, hell one of A/M's (the pioneer of the Mustang II clip being used as a donor suspension) chief engineers for many years will admit to that.

I just want to make sure everybody is aware that we do not use Mustang II suspensions. The only thing that somewhat resembles MII components is the spindles, and even those are different.

[kamaroman68]

Hey Matt Jones I purchased a Max G frame for my 68 camaro. I understand that it is not MII front suspension so what is it? I did not order the C5 setup. From what I understood when buying this frame from your salesman it was based on the MII suspension with a little geometry changed. So wouldn't this still be classified as MII suspension with some tweaks? And if I were to somehow break a control arm would a stock from another company drop right in? Without getting into all the crazy numbers can you tell us what is changed from the MII suspension? Chris

[red65FB]

[COLOR=black] OK, the tech is gone, I'm done

Come back! The whole point of this forum is to discuss how to make our old crap suspensions work less crappy - right? Did you get a chance to run alcino's numbers?

[chet]

interesting discussion! I have a question on my '79 ford truck I want to put a better handling suspension under it and I'm kind of limited on choices. fatmanfab has a MII setup but will it be that much better than stock? My main problem with the stock system is lack of ajdustability (and weight)

What suspension set-up would be a good start for a trans plant? or could a MII set-up be modded to give me some corner performance in a heavy truck?

[alcino]

I don't have numbers yet so don't expect anything from dennis. I will be out of town this weekend but after that I should have time to take a few measurements off my car to get the baseline and start putting together a version 1.0 of my future redesigned MII suspension. If Dennis is willing he can run the numbers and show us what the values are and if they are improved by the "redesign".

[silver69camaro]

Hey Matt Jones I purchased a Max G frame for my 68 camaro. I understand that it is not MII front suspension so what is it? I did not order the C5 setup. From what I understood when buying this frame from your salesman it was based on the MII suspension with a little geometry changed. So wouldn't this still be classified as MII suspension with some tweaks? And if I were to somehow break a control arm would a stock from another company drop right in? Without getting into all the crazy numbers can you tell us what is changed from the MII suspension? Chris

It's not based on the Mustang II suspension at all. We have the Mustang II spindles (which aren't exactly like the stock MII spindles), and designed the suspension from scratch. So the answer is no, it is not a "tweaked" MII design, and other components will not fit (only AME parts will fit). Some measurements are similar between the two, but as we all know, "similar" measurements do not produce the same end result.

Things that have changed from the stock setup are, but not limited to:
- Anti-dive
- Camber curve
- RCH height
- RCH migration
- SVSA
- Bumpsteer

And the list goes on. The suspension used on our GT55 chassis also uses MII spindles, but the geometry is heavily modified from our base in-house suspension. This proves that even though MII spindles are used, you can get great handling! But the similarities end at the spindles, and people can get that confused.

Let me know if you have any other questions!

[kamaroman68]

Thanks for the reply Mr Jones. I'm actually kind of glad you cleared it up for me. people at work were asking why I would put a mustang suspension under a camaro. I told them it was tweaked MII suspension. I will correct that statement. Chris

[kamaroman68]

So I kinda understand what you are saying but when I opened my rack and pinion unit it was a 74-78 mustang rack as well as the outer tie rod ends although coming from flaming river. So it seems that there are parts from the MII suspension being employed in the use of this suspension but geometry has changed. Thanks Matt Chris

[silver69camaro]

So I kinda understand what you are saying but when I opened my rack and pinion unit it was a 74-78 mustang rack as well as the outer tie rod ends although coming from flaming river. So it seems that there are parts from the MII suspension being employed in the use of this suspension but geometry has changed. Thanks Matt Chris

The rack doesn't have much to do with the stock Mustang II geometry. It's narrowed/widened to fit our specs, and we also use Pinto, Omni, and Opel racks when we see fit. So really, the rack that you have was just used because it has the correct pivot-to-pivot dimension for your suspension type (frame and hub width). The tie rod ends are used simply because they bolt up to the Mustang II spindles, and they're very durable. Again, nothing to do with stock MII geometry. Sometimes we use sphericals, too.

I think your rack may actually be a '79-'93 Mustang rack, not a Mustang II. If you want to tell for sure, the MII rack is 16" mount-to-mount, and the Mustang rack is 15.5" mount-to-mount.

[kamaroman68]

Yes Matt you are correct the rack is the later one as you stated. The outer tie rod ends are definitely 74 - 78 as I have the package in hand. But that pretty much clears it all up. Thanks Chris

[TBART70]

As far as I know the suspension I have is based on a mustang because of the spindles, steering rack and strut rod lower control arm set up. As mentioned before the similarities end there. It is built to the demensions of my car, control arm length, track width and so on. Supposedly the dimensions are suppossed to be a better design. I do not know exactly what the geometry is, but it is also hard to get an answer out of the guy who built it. I should have done my homework before I bought it, and the way he was on the phone answering my questions I should have known better an hung up on him. I will find someone at some point to help me figure this out so I can stop assuming that it will handle good, until I drive it and feel it I won't know. If the numbers look good before it is on the road great.

[murtah]

Tbart, your sub is from Martz, right? Getting info from ol' gary is like pulling teeth.

[TBART70]

yeah its from him, hard to get answers, was hoping R. Kirkindall would chime in he loves his chassis, maybe he could get some numbers from him?

[David Pozzi]

sorry if i ryled things up here.



Only the rubber bushings replaced with the poly ones. Everything else is factory, but the alignment settings.(-1.75d camber, 3.5d caster, 0.5inch toe out)

I agree with dennis about the wandering RC from the short arms, or so I think. When I'm hauling ass on the road course it can be really scary during transitions when the weight is being shifted from one side to the other. I don't know how to explain it other than the car starts to feel unpredictable and I say "oh *****!" in my head. Is that the RC moving dennis?

I also agree that there is room to improve. In the future I would like to get wheels with the most backspacing possible in the front, with taller dropped spindles(AFX?) or taller balljoints and making long control arms to fit. I'm hoping to get close to 3 more inches on the control arms.

Dennis do you still have that suspension program? Could I give you some dimensions on my ideas and see how they would turn out?

Al,
Perf Trends demo software has a 78 mustang II.
The roll center moves laterally a lot, it moves towards the loaded tire under roll.
The roll center is at ground level, goes below ground level under braking, there is only .3 deg neg camber gain per inch of bump, there is .8 deg camber loss relative to the ground at 2 deg pure roll, with no dive.

The A arms are so short they really hurt the geometry!!! The usual move to the upper A arm inner pivots does not help much.

[David Pozzi]

Al,

what is the distance (height) from lower balljoint center of pivot, to the floor?
What is the distance (height) from lower inner A arm pivot to floor?

Is there any room to raise the inner pivot of the lower A arm? Both front and rear pivots?
Does anyone make a drop spindle for a Mustang II? I've got an idea...

[TBART70]

David maybe you can answer my question. I know not having all the measurements plotted out for use on the computer is going to make it hard to answer. As stated in the first post, will making the lower control arm 3/4 inch longer make that much of a significant difference good or bad? thanks for any input.
-Tom b.

[David Pozzi]

TBAR70,
No, I dont' think so.
It's looking like the lower arm inboard pivot must be higher than the LBJ on the inboard side by an inch, and the upper arm inner pivot lowered an inch. You really don't want to raise the inner LCA pivot because you would then need to move the rack.

If you could find a drop spindle, then raise the car up an inch with taller springs or spacers, that would help get the lower A arm at a better angle, then lower the upper A arm pivot 2". The rack might not need to be moved this way, but the outer steering arm would have to be spaced up to where it was.

This is just a flat out guess at this point but something in that directon would help and be something to try on an MII suspension other than changing A arm lengths which is more difficult.

What I'm seeing is, the arms are too short both top and bottom, this makes the roll center move laterally a WHOLE BUNCH. It also stays very low at ground level even if you lower the upper frame pivot 1" or 2" by itself.

I tried raising the lower A arm inner pivot 1" and it got better but the Instant Center moves in very close, the RC moves up, there is less lateral RC movement, (if I did it right). This isn't the way you want to design a suspension from scratch, but at this point, we are mainly wanting the tires to stay reasonably flat on the ground and the RC to stay above ground as primary goals.

This was just a half-hour playing with the Perf Trends software so don't treat it like I spent a week on it please! I might take another look at it and change my mind about some of this, I was kinda sleepy when I did it.

If I had a MII suspension, I'd swap it out for something else quick! If that is not possible, longer A arms are needed. If not that, then the mods above I outlined are something to try. They really need to be refined and improved with more time invested than I have done thus far.

If you can't do the mods, then make the suspension super stiff in roll so the car doesn't lean, and crank in a lot of static neg camber. Lots of positive caster would be a big help and would reduce the camber losses I see.

I think the spindle has a KPI of close to 10 degrees, so positive caster of 6 or 7 deg would be something to experiment with, then see where the camber goes when you turn the wheel.

If you have this suspension can you take some readings of camber with the wheels turned full-lock, compared to straight-ahead? Or take a good pic straight in line from the front looking at the outer edge of the wheel?

[red65FB]

TBAR70,
No, I dont' think so.
It's looking like the lower arm inboard pivot must be higher than the LBJ on the inboard side by an inch, and the upper arm inner pivot lowered an inch. You really don't want to raise the inner LCA pivot because you would then need to move the rack.

If you could find a drop spindle, then raise the car up an inch with taller springs or spacers, that would help get the lower A arm at a better angle, then lower the upper A arm pivot 2". The rack might not need to be moved this way, but the outer steering arm would have to be spaced up to where it was.

This is just a flat out guess at this point but something in that directon would help and be something to try on an MII suspension other than changing A arm lengths which is more difficult.

What I'm seeing is, the arms are too short both top and bottom, this makes the roll center move laterally a WHOLE BUNCH. It also stays very low at ground level even if you lower the upper frame pivot 1" or 2" by itself.

I tried raising the lower A arm inner pivot 1" and it got better but the Instant Center moves in very close, the RC moves up, there is less lateral RC movement, (if I did it right). This isn't the way you want to design a suspension from scratch, but at this point, we are mainly wanting the tires to stay reasonably flat on the ground and the RC to stay above ground as primary goals.

This was just a half-hour playing with the Perf Trends software so don't treat it like I spent a week on it please! I might take another look at it and change my mind about some of this, I was kinda sleepy when I did it.

If I had a MII suspension, I'd swap it out for something else quick! If that is not possible, longer A arms are needed. If not that, then the mods above I outlined are something to try. They really need to be refined and improved with more time invested than I have done thus far.

If you can't do the mods, then make the suspension super stiff in roll so the car doesn't lean, and crank in a lot of static neg camber. Lots of positive caster would be a big help and would reduce the camber losses I see.

I think the spindle has a KPI of close to 10 degrees, so positive caster of 6 or 7 deg would be something to experiment with, then see where the camber goes when you turn the wheel.

If you have this suspension can you take some readings of camber with the wheels turned full-lock, compared to straight-ahead? Or take a good pic straight in line from the front looking at the outer edge of the wheel?

First of all, thanks for taking a stab at this Dave. I suspect the reason why some us are leaning towards the longer control arms idea, is that the moving the inner pivots around is going to be tough. The rack mounts right next to and laterally in line with the LCA.

After taking a long hard look, packaging wise, the areas of opportunity seem to be the following:

1) Lengthen LCA - moving lower ball joint outward. Seems to be space for a good 3-4" with corresponding offset needed for wheels.
2) Lengthen UCA - Lot's of room here.
3) Increase height of upper ball joint mount - room here as well.
4) Move UCA up - from what little I know of suspension theory, probably not a good idea, but certainly easy enough to do with some properly machined spacers.

Not saying this is what should be done, but fabricating solutions for these areas seems "easier" somehow.

[David Pozzi]

Thanks for the input.

I guessed moving the lower pivot would be a pain. I can tell that suspension was designed to understeer!

I was hoping a drop spindle was available. It would allow a downward slope to the lower A arm. If a longer lower A arm can be used with a late style FWD wheel with lots of backspace, maybe that would help. It sure wouldn't hurt!

If I get a chance, I'll look at a longer A arm and see what that does.

I'm preparing to run my car at a vintage club track day this Wed, so maybe after that I can spend more time with it.

[alcino]

hot little topic here.

Al,

what is the distance (height) from lower balljoint center of pivot, to the floor?
What is the distance (height) from lower inner A arm pivot to floor?

Is there any room to raise the inner pivot of the lower A arm? Both front and rear pivots?
Does anyone make a drop spindle for a Mustang II? I've got an idea...

Just got home and was motivated to measure.

lower balljoint to floor is about 7"(the spindle height was 10 7/8")
lower inner A-arm pivot to floor is 6 3/8"
trackwidth is 68 1/4" and the tires are 205/50/15.

So how does that look on paper? I already see the problem of the balljoint being higher than the inner pivot.

Also Heidts makes a forged 2" drop spindle.

So my initial idea is to use the drop spindle, Lengthen the a-arms at least 2.5 inches, and if need be use tall balljoints that add a 1/4 inch each. Can you run that David? or anyone else?

Thanks

[red65FB]

Forgot to add - I have the Heidts 2" dropped spindle - it at least appears to be a stout piece. On top of that, I also had to cut a coil off the spring to get it to sit right. With this set-up, the LCA's and steering rack arms are sitting level to the ground which I've been told is the most desirable position to minimize bump steer with the stock rack.

[David Pozzi]

Alcino,
I'll take a look at it Thursday or Friday night, I should have more time by then.
With most A arm suspensions, if you lower the car you get more neg camber gain, but this type is different.

[Norm Peterson]

trackwidth is 68 1/4" and the tires are 205/50/15.Just how was that measurement made? Outsides of the front tires? In that case, the wheel width would help better establish the center point of the contact patches.

Norm

[Mean 69]

The suspension used on our GT55 chassis also uses MII spindles, but the geometry is heavily modified from our base in-house suspension.

Huh? Really? Whatcha mean, Matt?

The funny thing about performance upgrades these days is that if it improves the performance, at some level it seems to be getting translated to "race car." Reality is the furthest thing from the truth. The media, advertisers/producers, and lay-people that have opinions all fuel the fire too. Not so funny to watch in many cases. Unfortunately, the average consumer gets bombarded by too much crap, and it makes making a truly informed decision, which is based upon facts, very difficult. Suspension systems are the top of the heap in terms of trying to get to the facts in the overall scheme.

Mark

[TBART70]

David I truly appreciate you taking the time to answer my question. But I think some of the info was lost in translation from my first post. I have a 1970 Camaro with a Martz chassis it is based on a mustang, only the lower control arm strut rod design and the spindles, I think. It is designed to fit the car so it is not just pulled from a mustang or mustang II. The lower control arm is 15 in. from pivot to center of balljoint, it is straight across. The new control arm from TCP (Alston) is 15 3/4 in. and the pivot is raised about 1 in. above the plain of the balljoint. I'm still learning about all of this stuff and apreciate the info, I know making these mod's without really knowing the effect is not a real good idea but I like to learn as I do things, I helps me put it in a real world situation. The reason I want to change things is I have made a few changes to the frame already, for strength and rigidity. Like I said in many previous posts I should have not bought it but I have it and I am going to use it. If I can improve the suspension without too much trouble great, if not I hope it handles decent enough for the money I spent. Live and learn( the hard way sometimes).
-Tom B.

[David Pozzi]

Tom,
If your A arms are longer than a Mustang II, it may not be so bad. How long is the upper arm?
All I'm working from is a Mustang II file, I'd need full measurements for the Martz suspension to really do anything helpful to you.

Sometimes your first loss is your best loss, meaning if you really want handling, sell your sub to someone who is a drag racer and look for something better. I hate so say that when I don't know for sure if your geometry is as bad as a stock Mustang II, so take it with a grain of salt.

[silver69camaro]

Huh? Really? Whatcha mean, Matt?
Mark

Somehow I believe lies more in that question that was it reads. :hmm:

The differences are stated in my post. In addition,
Shorter SVSA
Significantly more anti-dive
More aggressive camber gain
Roll/ride steer is deisgned to be more stable under high speeds, braking, and cornering
Drastically reduced roll center migration
More caster

Mark, I hope you weren't getting the impression that Mustang II setups are suitable for racing. I don't think you'll ever hear me say that.

[Mean 69]

No, all that makes sense, Matt, what I read in that statement was that the version used on the GT Chassis is not the same as what your "stock" product was. I read it to mean that the one used on Art's car was modified beyond what you guys already do, I didn't think that to be the case. You needn't read anything more into it than that, just worded funny.

M

[CraigMorrison]

Mark- The IFS setup that we use on the GT Sport chassis (Tri 5 Frame) is different from what our standard IFS is. Katz originally designed this suspension specifically for this chassis. As Matt said, it is quite a bit different from what we were using on our "street rod" chassis, but we are now using both styles on our custom chassis depending on what is being built.

Hope that this clears up some of the confusion.

PS- are you going to Coulmbus?

[Mean 69]

Ahh, I didn't realize that. Makes sense, thanks for the clarification.

Columbus? Probably, we hope to have some new stuff to show, including a car we are doing (68 Plymouth) that should be pretty cool. I think we are going to pass on the Power Tour, too far, so we will probably go there instead.

Er, sorry for the highjack...

Tom/all, there is a big difference between a Mustang II suspension, and a suspension system that is derived around the MII spindle. Once you start looking at ways to solve front suspension issues, you will quickly determine that the hardest part to find is a good donor spindle, MII's are/were popular candidates because of the rack steering, and they were a dime a dozen. Plus, if one outfit was doing something with the piece, it'd be pretty easy for another outfit to copy/improve, etc. There's nothing wrong with using this spindle and designing around it, the issue comes about when folks that don't understand the design issues muck things up.

With a car like yours, which is wider than a MII, the steering rack, it's placement, proper width, etc is another fun thing to overcome. My guess is that Martz used the stock rack width, pulled the control arms in towards vehicle centerline (making them longer, which in the VERY general case is good) to help mitigate bump steer. Frankly, that's not a really bad place to start with, through some analysis it is probably possible to come up with something that is decent. A 15" LCA is pretty darned good for a typical street car, but again, it is only ONE piece of a large puzzle.

M

[David Pozzi]

Tom,
Can you either provide full front suspension measurements or can you do a test of the camber curve from your sub?

I suspect it's not nearly as bad as a stock Mustang II.

I need distance out from F/R centerline to inner pivots and balljoints, then measure up from floor for the same points. I need front and rear pivot locations for the A arms, and their distance forward or rearward from a line drawn from lower balljoint to lower balljoint.

[Norm Peterson]

I'd kind of like to see those dimensions myself. Perhaps they could be posted?

Norm

[TBART70]

Thank you everybody for taking an interest in this. I'm assuming these measurements need to be taken with all components installed. The problem right now is the car is still in the fab stage. I can put all the parts on the chassis, but a full weight engine and nose of the car will be way off. I have a mock-up block in it now with my trans. I don't have tires for my new wheels yet but I have the old wheels and I think the tires are the same height. Thanks David ! I will try to get as many measurements as possible but I am still learning the lingo, I am way new at this so it might take some time to translate what you are looking for( great learning experience ). I still do not know how to post pics, if I could it might be easier to figure out.
-Tom

[David Pozzi]

OK,
Enough of this stuff! I"m PULLING RANK ON YOU GUYS. :throw:

NO more posts allowed off topic!

If I see any more posts that don't address the topic, I WILL DELETE THEM!
If you guys want to talk more on other topics, you can, but NOT HERE, please post a new topic in Outhouse and you can talk THERE forever.

YOUR MODERATOR

OK I successfully copied this thread over to Outhouse: https://www.pro-touring.com/forum/showthread.php?t=17432
Go there for any further off-topic discussions PLEASE!

I "Soft Deleted" most of the off-topic posts in this thread, they can be opened by clicking on them. I tried to leave anything that contained useable info. The Outhouse version contains all posts, -unedited.

[TBART70]

Some new info I got from Martz, the suspension is not based on a mustang, it is made from scratch. I asked what the spindles were based on, first I was told they were 67-69 spindles. Then I was told camaro's don't have racing suspensions, and no one makes a spindle to fit there design, this response was because I asked what they were based on so I could buy aluminum ones like ATS. I compared them to a 67-69 spindle , no match, 70 -77 spindle no match. I guess I am stuck with what I have. I do plan on changing the lower control arm to the one I purchased from Alston, they are much more sturdy even though I have to make a few alterations. Hopefully I can get some measurements in the future and get an idea what this thing is set up for.
Thanks for the help.
-Tom

[BRIAN]

I am no suspension guy but there are a lot of street and race cars using the Mustang 2 stuff. If this was several years ago all the MFG's would be bragging about using the Mustang components. Now nobody wants to advertize them


I had talked to Martz on a project and honestly didn't get very far with him answering any questions in regards to components used. He actually got aggravated when asked about handling mods.The Mustang 2 stuff is pretty easily spotted unless they are making there own version. The Heidts stuff has there name stamped on it so it is a little hard to miss. You have a good foundation and should drive and thean alter from there.


I would brace frame to reduce flex and then take the test it first and then make changes to suit your driving. What somebody else feels is s good suspension or driving characteristics might not suit your needs. Look at Porsche 911's VS Vettes? 2 very different handling cars that can be made to perform well although probably a better starting platform. It would be a greater challenge to use what you have as long as you feel they are safe. Modify to your desires and then go shopping from there. Too many guys on here talking about parts they have on projects that haven't even moved. Also great wealth of info. Always more impressed with guys making educated mods than buying the latest part

Call Marcus at SC&C he can set you up with some adjustable Mustang 2 arms which will make some adjustments easier. They were made by Pole Position but I think they changed names.

Good luck and I am interested on real driving impression evaluation as is and after mods are made. It is very rare that any post is followed up with before and after.

[David Pozzi]

Tom,
A basic measurement of camber change would tell a lot. If the sub has a fairly decent camber curve, or at least not a terrible curve, the car should be pretty decent.

You should also try to check bumpsteer once you have it aligned. All you need to do is measure toe, then open the hood and place some weights on the radiator support. I used some old cyl heads and clutches. When the front drops 1" measure toe again and see what the change is. If it changes 1/8" in toe, I wouldn't worry, that's not outstanding but good enough. If it changes by 1/4" you probably need to look for ways to fix it but that still may not be noticeable to many drivers.

I haven't seen any evidence of Martz understanding or caring about handling. - Too bad.
What looks bad to me is the torsional rigidity of that sub, there are large holes in the crossmember. Some boxing in of the crossmember and some gussets would help. I would also look at ways to run braces from the sub to the firewall but you may not want to go that far.
I did hear a report of their First Gen sub, -it positioned the front wheels about 1" forward of center in the wheel well. I don't know if they have fixed this or not.

[TBART70]

David I think I adressed alot of these issues. I boxed in the crossmember, I made bars from firewall to frame, I added tubing where the frame starts to rise by the middle body mount. I added plates and gussets to middle body mounts. I also added bars to the front engine crossmember forward to the lower control arm strut rod crossmember. I also bought a bumsteer kit from Steeda that fits my rack.

[David Pozzi]

I think you are in pretty good shape with all that.
What do they do for an anti-roll bar?

[TBART70]

I want to say it it similar to a speedway eng. Solid aluminum bars attached to heim ends on the lower control arms, solid splined bar attached to frame with urethane.

[David Pozzi]

I have to say most reports on this sub have been good, however I don't know how savvy the owners were on suspension.
The bar sounds good.

[David Pozzi]

There was a post here about a Lotus 7 chassis with a 351 Cleveland in it. I created a new thread for that subject:
https://www.pro-touring.com/forum/showthread.php?t=17614

[hssss]

Ignore this. Actualy it's a Windsor.

[David Pozzi]

Oops! :banghead:

[TBART70]

Now I can put up some pics.https://static1.pt-content.com/images/noimg.gif (http://img113.imageshack.us/my.php?image=10001877pi.jpg)https://static1.pt-content.com/images/noimg.gif (http://img504.imageshack.us/my.php?image=00000968zw.jpg)https://static1.pt-content.com/images/noimg.gif (http://img100.imageshack.us/my.php?image=00004671mv.jpg)https://static1.pt-content.com/images/noimg.gif (http://img117.imageshack.us/my.php?image=10002558ku.jpg)
I added steel to crossmember and to the front support, I lowered and re-did the engine mounts. Also added metal to the center body mounts and changed the trans crossmember mounts. I will be changing the lower control arms and I will post more pics of recent progress if anyone cares. Also a pic of my art morrison tri-4 bar.https://static1.pt-content.com/images/noimg.gif (http://img97.imageshack.us/my.php?image=camaro02843gs.jpg)
https://static1.pt-content.com/images/noimg.gif (http://img50.imageshack.us/my.php?image=10003551uy.jpg)

[BluEyes]

If you're lengthening the LCA by 3/4", definately take a look at those SC&C arms. You'll probably need the adjustability unless you want negative camber like a slammed Honda ;)

Hmmm, from those pics I'm seeing no anti dive, parallel axis steering and 0* kingpin inclination? Your scrub radius is going to be massive unless you can get rims that will fit over the steering arm and have some reasonable positive offset.
When viewed from above, is the steering rack inline between the outer tie rods?

What was wrong with the original Camaro suspension though? I know it's no C6, but 2G Camaros got a pretty good suspension.

From a few pages back: Baz, by changing toe, especially by 1/2", you are altering the initial angle of the steering arms and the tie rod lengths. Pretty sure that would have some effect on ackerman but hard to say how much.
I know one of the quick and dirty ways to calculate ackerman is to draw a line through each steering arm back to the rear axle so it would seem reasonable for there to be some effect.

[TBART70]

https://static1.pt-content.com/images/noimg.gif (http://img206.imageshack.us/my.php?image=10004473az.jpg)https://static1.pt-content.com/images/noimg.gif (http://img214.imageshack.us/my.php?image=10004448kh.jpg)https://static1.pt-content.com/images/noimg.gif (http://img393.imageshack.us/my.php?image=10004313go.jpg)https://static1.pt-content.com/images/noimg.gif (http://img380.imageshack.us/my.php?image=10004171fm.jpg)
the pics show the old lower control arm and the new one, I shortened the new one to the exact length of the old one, I had to install the bigger ball joint sleeve anyway so I made it shorter. Also made new strut rod and coil over mount. now i need to do the other side and get measurements for the whole thing and make any adjusments to it now before final welding and paint. (long way off, plenty of time)I will probably make a camber adjustment at the inner joint of the lower control arm, at this point static camber is only at -.2 and once i put it back together with weight in it it will be less. i don't want to find out when I go to align it there is not enough adjustment in the upper control arm. i know caster won't be a problem because the lower control arm and inner joint can be put where ever I need it to go, alot of room for adjustments. If the upper contorl arm was shortened I know it would have an effect on geometry, so would having a different length lower. I would like to take the measurements and find out what this thing has before I go any further. David if you are willing let me know how and what is to be measured. I want to thank everybody for there responses, I made me think, and made me want to change this thing.

[alcino]

What spindles are those? Martz? Are they heavy? cast metal?

[CraigMorrison]

Nice lookin' rear clip! Thanks for your business! :bananna2:

<threadjack over>

[TBART70]

they are welded together, the main part where the ball joints go are 1 part. I was told that no other manufacturer's spindle would work. I wanted to change them but as I stated before this is not "mustang based" as I am told. Also I will state again I should have gotten something else but this thing is making me think and learn.

Craig of course you come out with a three link, and I am a long way off from driving this thing. Can't wait to try it out. How much of an improvement is the 3 link compared to the tri-4bar?

[CraigMorrison]

I think you will be very happy with the tri 4-bar. Art hammers on the 55 (his favorite saying is "drive it like it's stolen" or close 2nd "drive it like a rental car") and the handling is phenominal. I've driven the car pretty hard as well, and haven't found its limitations yet.

PS- when the car is finished, send me some pics, we are always looking for cars to put on our website or in our catalog.

[TBART70]

I spent almost the last year tearing into this thing. Marcus from SC&C did the calculations for me and we made some progress. I have made major changes, I have tall ATS spindles now with Howe upper balljoints. I have chevelle steering arms on it but I am waiting for new aluminum ones to come and hope it cures some mis-alignment problems. I moved the rack for steering joint issues (not finalized yet) and steering arm length issues. I am changing the inner joints on the upper control arms, I have to shorten the upper to compensate for the higher inclination of the ATS spindle and the larger size of the new inner joints. I am also adding anti-dive to it, I had to cut off all the brackets and fab up new ones. I have learned alot about the geometry. I also bought a Longacre caster/camber gauge (nice product) to make measurements before and after. According to the analysis the bumpsteer was pitiful and the camber gain was too agressive. I should be able to get 4.5 to 5.5 deg. of caster and .75 deg of camber easily. I still have to fab and tweak but it is coming along. I had to sell of my brakes and spend alot more for C5 stuff. I had to lower the front strut rod to get more clearance on the tie rods. I bought better rod ends for them also, and added mis-alingment washers. I figured I should have sold this thing even for half price and bought another chassis along time ago. It probably works out to same loss of money, although I have a better (yet still limited) knowlegde of geometry. Thanks for all the ideas, and comments (some more than others). I will post up some pics soon for critique. Thanks to Marcus this thing will be better.

[TBART70]

I also added a lot to the structure for strength and changed to a bumpsteer kit that I made. The aftermarket one I bought had crap rod ends and way to big sleeves. I made new ones out of chromoly solid tube with better chromoly rod ends.

[David Pozzi]

Thanks for your report back. Sorry you had to do all that work, but I think in the end your car will drive and handle well with Mark's help.

David

[TBART70]

https://static1.pt-content.com/images/noimg.gif (http://img157.imageshack.us/my.php?image=1000922yw5.jpg)https://static1.pt-content.com/images/noimg.gif (http://img329.imageshack.us/my.php?image=1001279xz0.jpg)https://static1.pt-content.com/images/noimg.gif (http://img329.imageshack.us/my.php?image=1001276zb2.jpg)https://static1.pt-content.com/images/noimg.gif (http://img329.imageshack.us/my.php?image=1001282wt1.jpg)
https://static1.pt-content.com/images/noimg.gif (http://img527.imageshack.us/my.php?image=1001280ch3.jpg)https://static1.pt-content.com/images/noimg.gif (http://img49.imageshack.us/my.php?image=1000851uc7.jpg)
tall ATS spindle, billet steering arms, C5 brakes on the way. changed the strut rods twice, modified chevelle arms then bought aluminum ones. added anti dive, changed inner upper joints and mounts. made different tie rod sleeves. wasted alot of money on new parts just to toss out some of the junk I bought. The rod end on the bumpsteer kit is junk mild steel it bent by hand when it bound up when I was checking angles. When will it end.:crying:

[796spdbu]

1.Where did you get the joints used in the c/a's

2. Where did you get the brackets and offset ecentric bushings and mounts

I love all the fab work,just like yourself,I am also learning the suspension geometry.Nice work!!Any info you can give me would be greatly appreciated.

[TBART70]

the upper joints are from currie, johnny joints.
the brackets with the eccentrics came with the chassis, I cut them off and may not make new ones.
thanks for looking I'm still learning.

[796spdbu]

Thanks,looking good so far.If I my ask....Cant you keep the eccentrics to aid in doing your alignment.I have a tubular k-member with heims in the control arms on my 95' camaro,and if i didnt know my local mechanic pretty well he would have charged an arm and my first born to keep removing the c/a to get the adjustment right.Just my two cents worht of questions..Nothing behind it,just wondering.I helped to do my alignment(I used to do alignments at the local shop when my day job was slow)and I know how much adjutable c/a's can be a pain.I also know that you can get them close before you take it to get the final settings,but just tring to help.Ok let the bashing begin for my silly comments....

[Jayco_Automotive]

You know, i read this post and the Martz Chassis suspension is not flimsy and also its not a Mustang II or based upon a Mustang II suspension it is of there own design. These are designed for racing
however are street legal and are cheaper than most other IFS systems. Also in parting why didn't you call Andy at martz for the geometry, but since you went and raped one of the best suspensions made oh well.

[baz67]

You know, i read this post and the Martz Chassis suspension is not flimsy and also its not a Mustang II or based upon a Mustang II suspension it is of there own design. These are designed for racing
however are street legal and are cheaper than most other IFS systems. Also in parting why didn't you call Andy at martz for the geometry, but since you went and raped one of the best suspensions made oh well.

Oh boy :spank2:

[novanutcase]

You know, i read this post and the Martz Chassis suspension is not flimsy and also its not a Mustang II or based upon a Mustang II suspension it is of there own design. These are designed for racing
however are street legal and are cheaper than most other IFS systems. Also in parting why didn't you call Andy at martz for the geometry, but since you went and raped one of the best suspensions made oh well.
:bsjerk:


Oh boy :spank2:

LOL!!!!:lol: I was just imagining what was going through your head when you read that post!:getout: :rotfl:

[TBART70]

Thanks,looking good so far.If I my ask....Cant you keep the eccentrics to aid in doing your alignment.I have a tubular k-member with heims in the control arms on my 95' camaro,and if i didnt know my local mechanic pretty well he would have charged an arm and my first born to keep removing the c/a to get the adjustment right.Just my two cents worht of questions..Nothing behind it,just wondering.I helped to do my alignment(I used to do alignments at the local shop when my day job was slow)and I know how much adjutable c/a's can be a pain.I also know that you can get them close before you take it to get the final settings,but just tring to help.Ok let the bashing begin for my silly comments....

no silly comments. I figured when I build it I will dial in the caster/ camber and then fine tune it with height and all the other adjustments. The eccentrics made the old bushings get cocked in the brackets when I got the camber and caster where I wanted it. So I figured I scrapped the rest of it why not change the uppers.

[TBART70]

You know, i read this post and the Martz Chassis suspension is not flimsy and also its not a Mustang II or based upon a Mustang II suspension it is of there own design. These are designed for racing
however are street legal and are cheaper than most other IFS systems. Also in parting why didn't you call Andy at martz for the geometry, but since you went and raped one of the best suspensions made oh well.

As in a previous post I did find out that it was not Mustang II. Although I did inquire about a few times and got three different answers from Martz. I talked to Andy once ( nice guy ), it was about the steering, I did not ask him about the whole thing because I assumed (oh boy) it had good geometry ( was I wrong ). It is very flimsy, it flexes almost half and inch when you jack it up. The spindles were fabricated and the holes for the tie rods and ball joints did not match the taper. It has no anti-dive, the bumpsteer was way off, the camber gain was too agressive, I had to move the motor mounts because the bell housing was hitting the fire wall. Now I know moving the motor back is good for weight distribution but the problem was it was too high , usually the motor would be lowered and moved back not up. I wish I did not have to fix this thing I wish it was the best out there because I have no problem spending money, the only problem is I assumed ( there's that word again ) for that kind of money it would have been better. At the time no one made a chassis for my car yet so my options were limited. Also he was closer than other shops (wrong way to pic a chassis). Compared to my Art Morrison Tri-4bar the quality was not there. Are you basing your comments on your own measurements or are you going by what they have told you? Do you own one? Did you install it? Jack up your car and measure the flex. How can you say it is one of the best, no one has ever posted any numbers of one, geometry wise or real world testing in a car compared to stock. And why if it is so great that no one from Martz ever posted to dispute the argument like all the other manufacturers do. I would love to be proven wrong. Also don't forget I know nothing about suspension geometry, fabrication and chassis building. I am just some guy building a car and now if I saw this thing for the first time I would say no thank you and call someone else.

-Tom

[jmartz]

My name is Jeri Martz and it has come to my attention that I needed to speak with my brother Andy and clear up some things on here.

In Response to this post:

Our frames are far superior to the original stock frame. They have been designed to lighten the front while making it stronger for an optimal racing sub-frame/suspension system. You can look on our website on our customer page and the magazine articles page to see just what our customers are able to do with our systems:

http://www.martzchassis.net/page8.htm
customer page

http://www.martzchassis.net/mag
magazine articles and features

Please also note that these are only a few of our customers cars that have made it into the magazines. I have a few more sets that I have not had time to load onto the website yet.

This is Andy's response to your technical issues. Please note that he did not have time to go over the entire post from beginning to end in this forum and is only replying to the single post made on 5-28-07.

All frames have some flex in them. I'm sure that the stock frame flexed just as much if not more. You could be seeing the movement from the body bushings.

We use the same tappered reamer and ball joints that all of the race shops acrossed America use, so if ours don't match, then neither do alot of the NASCAR teams.

Performance suspension systems do not need anti-dive. Anti-dive was designed for production cars to keep softly sprung cars level during braking.

Our bumpsteer is not "way off". We spend a lot of time with precision guages working out the bump steer, then we build our jigs from these calculations. We work it over 3" in both compression and rebound and you will never see that much travel on a street car.

As for our camber gain: According to most professional Road Racers our's is not aggressive enough, but we designed our system to both handle great and produce desireable tire wear.

Our motor mounts were jigged off a stock subframe. Did you use the short GM mounts? There are 3 different heights. Did you use and aftermarket bellhousing that is built heavy to protect from flywheel shatter? Did you use new body bushings or the 37 year old set on the car? All of these can affect that clearance. We did not lower the engine for the fact that we would rather our crossmember drag instead of your oil pan, in case there was an incident. It would be less costly.

As for no one from Martz Chassis posting, we are hard working Americans making a living doing what we love. The same people that answer the phones and questions are the same people that build our products, so our time is very valuable and we can't spend alot of time in forums. I usually spend all day long answering emails from Customers as I answer the phone, take orders, place orders for parts, ship products out, make the catalogs, and update the website. Though we are an international business, we are still a family run business. We would not have even known about this had not one of our many happy cusomters pointed it out. We would never have known you posted this and were unhappy. Andy and I are very sorry you are unsatisfied with our product, but we also realize that in any business, you cannot please everyone, and of the thousands of customers that are out there running our sub-frames that we've sold to them, if there are 1 or 2 unhappy customers, well I guess we'll have to take those odds.

Thank you,
Andy and Jeri Martz
Martz Chassis INC

[silver69camaro]

Performance suspension systems do not need anti-dive. Anti-dive was designed for production cars to keep softly sprung cars level during braking.

I am in no way saying "I'm right and you're wrong", but can you elaborate on this? I'm intrigued on the theory behind it. What kind of spring/wheel rates do you typically employ?

[jmartz]

As I mentioned before, Andy doesn't have time to post on these. I'm actually supposed to be answering emails right now and ordering parts. I'll get Andy's response and post it within the next day or so. Just give me a little time to get the answer, I'm not a tech. However, according to the Art Morrison Catalog, it doesn't look like it uses much anti dive either. I would in no way cut on Art Morrison Enterprises, as your product is very well engineered also.

thanks,
Jeri

[silver69camaro]

Thanks for the compliments. I understand it's difficult to answer emails and stay atop of forums, we know how that is. Again, I'm just curious, and I realize there is more than one way to skin a cat.

[Norm Peterson]

. . . I'm intrigued on the theory behind it. Anti-dive normally implies caster gain, which affects bumpsteer (the steering arms move vertically as the knuckle rotates as seen in side view while the rack/centerlink does not).

Greater amounts of anti-dive may also result in more ride harshness while braking hard on rough pavement. The reaction force that is partly "holding up" the front end comes right through the suspension links themselves, rather than through the springs/shocks, and even soft bushings are stiffer in terms of lb/in than suspension springs. So if you (or your customers) are generally tolerant of a slightly firmer ride over normal roadway unevennesses, you won't need as much A-D to keep you off the bump stops under any given set of braking circumstances.

Norm

[silver69camaro]

I understand, I'm just suprised that no anti is used at all. I guess I shouldn't assume that "no anti dive" means zero...he might mean much less than a stock vehicle, which I fully agree.

I use some anti in our IFS setups, but not a whole lot. 2 to 7 degrees on the UCA, depending on the setup.

[TBART70]

I am a hard working American spending my money on something I was not happy with. I should have questioned it better,but I did not talk to Andy about geometry. My few calls and e-mails were with mixed results. It was my perogative to cut this thing up. I took it upon myself to do so and blame no one else for my actions. But from what was measured and calculated in a computer program it was not optimal and I decided to change it. I was not happy with the workmanship or qaulity, I made these deductions after having it for almost two years, and was not going to send it back and get a refund. I bought it and now I own it. I did not want to get this involved in chassis design and fabrication that is why I bought one. I did not want to get in a debate about it either. This forum has very smart people on it and the questions that were asked got answered and I was not happy about the answers.

new stock height solid body mounts, stock dimension bell housing from keisler,

I'll ship the spindles back for a refund, they do not match the tapers.


My name is Jeri Martz and it has come to my attention that I needed to speak with my brother Andy and clear up some things on here.

In Response to this post:

Our frames are far superior to the original stock frame. They have been designed to lighten the front while making it stronger for an optimal racing sub-frame/suspension system. You can look on our website on our customer page and the magazine articles page to see just what our customers are able to do with our systems:

http://www.martzchassis.net/page8.htm
customer page

http://www.martzchassis.net/mag
magazine articles and features

Please also note that these are only a few of our customers cars that have made it into the magazines. I have a few more sets that I have not had time to load onto the website yet.

This is Andy's response to your technical issues. Please note that he did not have time to go over the entire post from beginning to end in this forum and is only replying to the single post made on 5-28-07.

All frames have some flex in them. I'm sure that the stock frame flexed just as much if not more. You could be seeing the movement from the body bushings.

We use the same tappered reamer and ball joints that all of the race shops acrossed America use, so if ours don't match, then neither do alot of the NASCAR teams.


Performance suspension systems do not need anti-dive. Anti-dive was designed for production cars to keep softly sprung cars level during braking.

Our bumpsteer is not "way off". We spend a lot of time with precision guages working out the bump steer, then we build our jigs from these calculations. We work it over 3" in both compression and rebound and you will never see that much travel on a street car.

As for our camber gain: According to most professional Road Racers our's is not aggressive enough, but we designed our system to both handle great and produce desireable tire wear.

Our motor mounts were jigged off a stock subframe. Did you use the short GM mounts? There are 3 different heights. Did you use and aftermarket bellhousing that is built heavy to protect from flywheel shatter? Did you use new body bushings or the 37 year old set on the car? All of these can affect that clearance. We did not lower the engine for the fact that we would rather our crossmember drag instead of your oil pan, in case there was an incident. It would be less costly.



As for no one from Martz Chassis posting, we are hard working Americans making a living doing what we love. The same people that answer the phones and questions are the same people that build our products, so our time is very valuable and we can't spend alot of time in forums. I usually spend all day long answering emails from Customers as I answer the phone, take orders, place orders for parts, ship products out, make the catalogs, and update the website. Though we are an international business, we are still a family run business. We would not have even known about this had not one of our many happy cusomters pointed it out. We would never have known you posted this and were unhappy. Andy and I are very sorry you are unsatisfied with our product, but we also realize that in any business, you cannot please everyone, and of the thousands of customers that are out there running our sub-frames that we've sold to them, if there are 1 or 2 unhappy customers, well I guess we'll have to take those odds.



Thank you,
Andy and Jeri Martz
Martz Chassis INC

[TitoJones]

Our frames are far superior to the original stock frame. They have been designed to lighten the front while making it stronger for an optimal racing sub-frame/suspension system.

Welcome to Pro-Touring. While we are not as harsh as the guys at Corner-Carvers.com we do like when manufacturers put some sort of tech to back up a claim. I know what a stock frame is capeable of, so I'd love to hear specifics on what makes your products "far superior".
Things like camber gain per inch of travel, bumpsteer figures, total caster, etc will help those in the know make a sound unbiased judgement of your products.




All frames have some flex in them. I'm sure that the stock frame flexed just as much if not more. You could be seeing the movement from the body bushings.

I know you guys didn't sift through all 4 pages of this thread, but from the 1 picture I looked at of your frame mounted to his car it was with Global West solid aluminum body bushings. Your frame has more flex in it that a factory one does. Get Frank from Prodigy customs in here and he will tell you all about it. I think you guys even suggested adding front down bars to help reduce the flext on your frame. All the factory ones I've done don't require this extra support. Check out this thread while you're here: https://www.pro-touring.com/forum/showthread.php?t=1479&highlight=flex+martz


We use the same tappered reamer and ball joints that all of the race shops acrossed America use, so if ours don't match, then neither do alot of the NASCAR teams.

Which taper is this? 7 degrees? 10 degrees? You need to provide something for us to research, not just claim X is better than Y because you said it was.


Our bumpsteer is not "way off". We spend a lot of time with precision guages working out the bump steer, then we build our jigs from these calculations. We work it over 3" in both compression and rebound and you will never see that much travel on a street car.

So what is your total bumpsteer figure over 3" of suspension travel?
I'll go first- On our AFX spindle we have it down to 0.030" over 4 inches of suspension travel. I'll never claim zero like most manufacturers do, but that is as minimal as we could get it on a stock frame.


As for our camber gain: According to most professional Road Racers our's is not aggressive enough, but we designed our system to both handle great and produce desireable tire wear.

Again- What is your camber gain per inch of suspension travel? I'll go first again-
On our AFX spindle we set the static camber to .5 degrees negative. We have .9 degrees of camber gain per inch of travel.

I'm looking forward to seeing some tech brough back to the table, and I'm excited to see another subframe manufacturer on the boards. Again welcome to our corner of the interweb.

Tyler

[TBART70]

Is a Viper a stiffly sprung car, how about a C6 Vette, I think they have anti-dive built in. I know I was staring at one, a Viper that was in my garage that I was working on and wondering what degree of anti-dive it had, not wondering if it had any. thanks Mark, Matt, Norm, Frank, David, Tyler and everybody else who helped me.

[jmartz]

I will be going to visit Dad this weekend, as he is retired now, and I'm going to have him answer the tech questions if he has time. Andy has been too busy to even look at the post, so as of now I am at a stand still. I only do sales and general questions.

Dad (Gary) founded Martz Chassis a year before I was born (giving away my age) in 1970 and though I grew up around it, I'm not knowledgeable enough with the tech to answer it. Dad had me join the company for artistic/advertising reason. I am an Arts/English major, so again, I'll just have to get together with him on this and get back to you as soon as I can.

[Jayco_Automotive]

Hey, Tom i have a quick question even if this gets me banned, i have to say it you and your buddies have been flaming Andy Martz suspensions. So im going to flame you and David Pozzi. First of one of you asked if i have one of Martz's suspensions. Answer is no i dont. I spend usually at a minimum two days a week at their shop. I know how they are made, i know the geometry. I however will not expound upon it as it is a trade secret. Also as for flex there is no suspension in production that doesn't flex. But enough of that. You critized the chassis without ever running it, and after you dissassembled and hacked it up you want to return the spindles for a refund after 3 yrs. Thats a lil insane don't you think. Also everyone wants to know the benefits of the Martz subframe. Well to begin with it is 200 lbs lighter than stock. It features a welded box channel constuction instead of riveted C channel construction. Tubular control arms with energy suspension urethane bushings, eccentric bolts for quick caster and camber adjustments, standard or drop height spindles, adjustable height: standard height to 3” lower. Front mounted rack & pinion steering: power or manual. there is just a few benefits of the Martz system. And also to state just because i can its not based on a Mustang II suspension.

[TBART70]

I guess you don't understand sarcasm do you. Trade secret, all you have to do is measure it and enter it in a computer for analysis and when a true suspension engineer looks at it and says you should change it then I would start to take a look at the best possible solution. How do you know the geometry, did you measure it. I did talk to a few people who have it and are happy, very happy. I didn't tell them they did not know what they were doing I just asked what they did with it and how did it drive. Check this board and the second gen board. There are people out there that are happy with this set-up, I'm am not. We know its not mustang based that was stated last year. It is dirt track/asphalt based. Check your facts. I criticized it before I got it on the road because of the things I started to question, then learned a lot about what was wrong and needed to be fixed. I know it is just a street car and won't be raced, if I left it alone it would have worked fine. But when a stock chassis with aftermarket parts has better numbers I get a little concerned (this is a fact).

[parsonsj]

Let's stay with data, and avoid making this personal please.

I'd like to know more about why the Martz geomety is considered a trade secret. My take is that I'd never buy a replacement front clip without knowing its camber gain, side scrub, scrub radius, and bump steer. Roll center, and dynamic roll center would be welcome too.

If Martz considers those numbers proprietary information that's their business, but I consider that information to be just as important as knowing the hp and tq ratings of an engine.

jp

[Jayco_Automotive]

So lets see your numbers of an improved stock being better i keep hearing numbers but never see any. I want to see both your orignial measurements of the martz chassis, them your factory and the new geometry of you newly " improved" suspension/ custom fabrication.

[jmartz]

As i stated before, I'm not a tech. We supply a parts list that includes caster, camber and toe in numbers for each buyer. These numbers depend on the application the owner will be using his car for.

As far as Geometry, we use professional front suspension geometry software.

As far as trade secrets. We have had copycats. Not too long ago a "gentleman" called in for geometry information. We later found this same person peddling "Martz Chassis IFS" systems on his cars in Carlisle. He even used our oval logo stickers on the shocks, the same as we do. This is the reason we tend to not give out this information so freely. If we have a customer that needs help, we will help them. I personally do not remember tbart70 calling in for tech info, but I handle hundreds of calls a day. Although, since this posting was brought to my attn, I did pull his parts list. Now based on what he would have told us when he ordered the front, his caster should have been set at 3, camber .25, and toe in 0. This is for a standard 70 Camaro. I realize you gentlemen are not idiots and much more knowledgeable in tech than I am so i'm sure this information falls far short of what you really want to know. As I said before, I'll be visiting Dad this weekend and will try to get your answers. Andy is EXCESSIVLEY busy right now, anyone that races knows how busy race season is. It's Friday and he's loading up the race car, so there is no chance on God's green earth I'm getting any info out of him today.

[parsonsj]

So lets see your numbers of an improved stock being better i keep hearing numbers but never see any. I want to see both your orignial measurements of themartz chassis, them your factory and the new geometry of you newly " improved" suspension/ custom fabrication.Jayco, who are you asking? Tyler has answered that question for his (ATS) stuff. You can poke around on my website to see what I've done on my car.

You are claiming that Martz doesn't want others to know his numbers because he considers it proprietary information. That may be true, but I would think that counter-productive to a savvy buyer.

jp

[parsonsj]

I did pull his parts list. Now based on what he would have told us when he ordered the front, his caster should have been set at 3, camber .25, and toe in 0. This is for a standard 70 Camaro. I realize you gentlemen are not idiots and much more knowledgeable in tech than I am so i'm sure this information falls far short of what you really want to know. As I said before, I'll be visiting Dad this weekend and will try to get your answers. Andy is EXCESSIVLEY busy right now, anyone that races knows how busy race season is. It's Friday and he's loading up the race car, so there is no chance on God's green earth I'm getting any info out of him today.Jeri, thanks for dropping in and trying to set the record straight. We'd like very much if you can provide more information. The numbers you list are only initial alignment settings, and don't cover the dynamic kinematics many of us need to make buying decisions. The mods at PT.com will make sure that you are given equal say, and we'll prevent any smear campaign from happening.

jp

[jmartz]

Thank you very much. I've just been slightly anxiety stricken over this, as I had no clue until last week this was being discussed here. I had signed up years ago for the forum but just, well as stated before, I'm not a tech and felt extremely intimidated by the fact I don't know this stuff off hand.

[chicane67]

JP~ I believe that his comments were directed toward Tom and the recent modifications he made to the existing sub frame.


... So im going to flame David Pozzi.

Uhm... dont go there. It's in your best interest not to... to say the very least.


I however will not expound upon it as it is a trade secret.

I am interested as well, as to what makes it so very much improved.

By the way, it's not a "Trade Secret". It is company proprietary. Im in the trade... so why is it a secret from me ?? I know, I know... semantics. You however, have added... ZILCH, NADDA, ZERO... to this discussion with any technical experience or merit. Not to mention that your list of "benifit's" is quite laughable.

So whadda say we tone it down a little ??

Jeri~ Welcome. Good to see you get in here and get involved. I can understand your anxiety... especially jumping into this thread blindly, as you have. Just remember, a little thick skin will go a long way around here. There are a lot of technically savy individuals here that are somewhat passionate about simple kinematics. So it's not that hard to expect the heat, when the more experienced of this site get berated by an FNG with no understanding of the theories envolved or cannot back up their opinions with some sort of emperical knowledge.

Needless to say... there are many waiting with baited breth.

[Jayco_Automotive]

I assumed since everyone was so quick to flame the quaility of the martz chassis that, no one would mind me challenging those who made the claim without substantial info to prove it. And also i found it offensive that everytime someone asked about martz frames that a certain few were drving away customers. This in its self is unprofessional. Had this whole situation been carried out in a professional and non-imflamitory fashion i would have merely set back and mused at the ramblings of one unhappy customer. I have seen the quality of Martz Chassis products and have assembled and installed them. If you doubt the quality and durability of them i can provide documented evidence of one of my friends, Rex Johnson, who wreacked his Jeep Willys, and the chassis and the roll cage both Martz survived intacked. Pretty good feat consivering it end over ended several times. As for measurements ill get those for you if it will help the situation to calm down. As for flaming i will stop if those certain few agree to stop directing potential customers to view on isolated unhappy customers view on a great system.

[parsonsj]

Had this whole situation been carried out in a professional and non-imflamitory fashion i would have merely set back and mused at the ramblings of one unhappy customer.Sorry Jayco, I gotta disagree with this assertion. This thread has been moderated heavily from the start. Tom's posts are very much not ramblings, but actually show real understanding of suspension theory and fabrication. The people who have participated in this thread are among the most knowledgeable on the site.

If you doubt the quality and durability of them i can provide documented evidence of one of my friends, Rex Johnson, who wreacked his Jeep Willys, and the chassis and the roll cage both Martz survived intacked. Pretty good feat consivering it end over ended several times.This isn't evidence of good suspension kinematics. I'm glad your friend is all right, and I'm glad to hear the welding was sound.

As for measurements ill get those for you if it will help the situation to calm down.Jeri Martz has said she will try and provide them, but additional data will be welcome.

As for flaming i will stop if those certain few agree to stop directing potential customers to view on isolated unhappy customers view on a great system.You need to stop flaming now. It is against the rules on this site. If you don't like the opinions being shared about Martz products, you can provide alternate data, but personal attacks will not be tolerated.

jp

[Jayco_Automotive]

I really fail to see how challenging someone's assumption or conclusion that a chassis is incorrect is flaming. Warning customers to say away from a product that was never tried or road tested to see how it performed is prejudicical at best. I personally could careless if he cut, fab'd and mod'd his frame. But to say that it is incorrect or inferior without proper testing is baised. Everything doesn't work as it appears on paper, anyone who is an engineer can relate to this statement. As far as flaming goes im fine with not getting personal, however i do have issues of sitting back and watching ppl being conviced that a suspension or product is substandard without proper representation. As for Gary Martz lack of phone skills, that i will agree with that. He could have been more forthcoming with info and tech support and that along with health reasons is why he has chosen to retire and leave the business to Andy. Also it would have been professional for anyone that had a problem with a Martz Chassis' products to contact them and workout any said short comings. I will guarantee that Andy will be eaiser to deal with on any tech issues.

[jmartz]

here's at least a start for you guys, there is only one measurement but it gives a close up of parts.

http://www.martzchassis.net/camaroexplosion

Please excuse my ignorance, but are we just looking at the measurements for just the 70 Camaro here? There are so many different measurements for the different years, and then add to that we make a wide track too....

[BRIAN]

Usually do not get involved but...

I have to say that I took the posts since day as showing that their was a problem with Martz's chassis. Why is it wrong for a shop to defend their product?? Why do they have to give detailed measurements of their products? There are some pretty big names on here that everybody raves about that hasn't posted up any information at all?? It just does not make any sense to do so. Why not just post a blueprint so it can be copied for free?? That is business not an attempt at hiding anything.

There are tons of suspension suppliers to choose from. If you did not like the set up why did you buy it?? Am I wrong in saying that the so called problems were in fact an opinion based on how someone wanted thier suspension to function? There are tons of different theories on how something should work and you are to choose which suits your driving style and application. How is a one generic type sub supposed to cover all the different tires sizes, car weights, ride height, etc. They don't instead it is a middle of the road piece. If you want a specific geometry than you custom build to suit your exact application. Does that mean any car that doesn't have a certain suspension design can't be competitive?? Was there a quality shortcoming or failure??? If so that is info that needs to be addressed and answered.

Take 2MUCH, you had perfectly good AM stuff but modified it correct? Did AM post their info as it must have also had a problem since it had to be changed??? No, it was changed because you wanted a particular set up for your car. By the way the color and wheels are killer. Sorry had to squeeze that in.

I am not arguing with anybody and want to make that clear. Since the 1st post I just do not understand why the sub wasn't sold and replaced by another it would have been cheaper and better than patching up what didn't work for this particular set up.

That being said I will also say I attempted to buy a sub from you guys years ago and you wouldn't asnwer a single question, I purchased elsewhere. Your product didn't fit my need, doesn't mean it is poor quality or wouldn't perform in somebody elses set up.

Please keep posting the suspension build up but I guess just leave Martz out of it as you never even drove it??

[TBART70]

Like I said it was a learning experience to say the least. I already started to modify it way before I learned a few things about geomtry. I made an uninformed purchase. I knew very little about geometry at that point, I did not ask the right questions, even if they would answer them or not. I added a couple of braces to it and added the firewall bars, I also welded on the Z-bar bracket for the clutch. Drilling and welding on it I didn't think 2 years later they would not have been too keen to give me my money back. I made the purchase based on location and a few recomendations from people who had it, and still like it. I know for what the type of driving I will be doing it would have been fine. The things I did to make it more rigid should work well. I said I should have sold it if I knew what all the changes were going to cost me in the end. I said before, I bought it I changed it and it is my fault no one else's but me. Anyone knows how a project like this can get carried away in a hurry. Let me tell you it did, change one thing get ready to change two or three others. I don't really care if they post there numbers or not, I don't have their suspension anymore. My original question was for making a modification and how would it affect the geometry, not what the geometry was. It was later on that I decided after discussing this with others that have had or seen or installed it that I wanted to make a change. I was not happy with the flexing issue, I was not happy with the placement of the engine, I was told by Gary the he puts the engine in the center of all his chassis' and thats approximatley where it was. For my car that was not going to work. I was not going to ship it back to him and ask him to move the mounts, I bought some steel and did it myself, now it is where I want it the shifter comes up in exactly the right spot, the height is where I want it. I'm sure it cost less for the steel and some time than it would to ship it back. And how was he going to get it where I wanted it without my trans and engine. I put the stock frame back in, made measurements, put the new frame in without the mounts and installed the engine. Positioned it to the stock frame measurements and made new mounts. We can argue all day about that problem, I have limited pictures of that part of the project, if I new it would come to this I wish I did have more. Some other issues were the trans crossmember mounts, and the rack positioning for steering linkage angles. I was not going to send it back for modifications that may or may not come back to where I wanted them. Because of the lack of comunication on the phone I felt my concerns would not be treated correctly. So I took it in my hands and now all the issues have been addressed. I still have a lot of work to do, was it worth it, no! I should have sold it or returned it but three years ago nobody made a chassis for this car, atleast a bolt in sub that is. And there was no aftermarket parts available yet. My choices were limited so I bought it. The geometry issue came later, I had it measured and was not happy with the answers, I made a change. I did not like the quality of some of the components and found better ones to replace them with. Yes it cost me alot of money and time, but I learned alot, had fun fabricating and welding. Made many rookie mistakes and paid the price. In the long run it will be close to what I want. I know what the numbers are going to be know and will suit my needs. It has components on it that I feel are better quality. If someone else wants to buy it go ahead. I would love to see more feedback. But like I said before I don't care what the numbers were, I have that all plotted out, I care what they are now. If the numbers were off how would driving it make them any better. My point is I want it to have the right numbers before so I don't have to change it when the car is done, atleast it is still in the fab stage where changes are easier. They can defend it all they want, they should. I was not happy and made a change based on what advice and findings others helped me determine. I asked a question and got ridiculed for trying to improve on something I purchased. I did not ask for them to make any retribution for what I found to be wrong. I should have, I learned alot in three years of working on it, found some very smart people to help and in the end it will be better. I don't know what else to say. The whole original question has been lost long ago. Even if I never stated who's chassis it was the question was over looked by some, that is fine, others tried to help me find a remedy, and I did with their help and my learning. I found fault with it and decided to fix it myself. I'm sure there is no one out there that has purchased a product, was not happy with it and didn't bad mouth the manufacturer, that never happens in this world. I'm sure I missed a few points but I'm better off working on the car than to keep coming on here ( we all know I will) and getting told I'm wrong. Thanks again to everybody that has helped.

-Tom

[zbugger]

Are we done here? I think so.