Martz Chassis 4 link

[jamesg602]

I am in the process of deciding on a 4-link for my 68 Camaro. I have been leaning toward DSE for the Qudra link but have seen the martz setup and started comparing. 1) The martz if a few hundred bucks cheaper, and 2) no mods to the back seat /floorpan. I am wondering if anyone has any specific advice or expirience with the martz setup? I will also be purchasing a minitub kit from martz or dse depending on overall qulity of the setup. :banghead:

[Iburyyou]

does the Martz 4 link come with the spings for $1250. I'm using the dse. I know it messes with the rear seat a little but in my opinion the Martz looks like it was just thrown together to copy the dse. I could be wrong but on their website it looks like they didn't even have time to paint it let alone test it

[madmax]

I am in the process of deciding on a 4-link for my 68 Camaro. I have been leaning toward DSE for the Qudra link but have seen the martz setup and started comparing. 1) The martz if a few hundred bucks cheaper, and 2) no mods to the back seat /floorpan. I am wondering if anyone has any specific advice or expirience with the martz setup? I will also be purchasing a minitub kit from martz or dse depending on overall qulity of the setup. :banghead:

I would be interested in hearing about this as well, even though I'm already committed to the DS&E unit.

Max

[rickk]

I have the martz 4 link in my camaro . gary does a good job also he has in the chassis bez for 30+ years .
rick kirkindall

[jamesg602]

does the Martz 4 link come with the spings for $1250. I'm using the dse. I know it messes with the rear seat a little but in my opinion the Martz looks like it was just thrown together to copy the dse. I could be wrong but on their website it looks like they didn't even have time to paint it let alone test it

Yes it comes with springs (coilovers) and I was not aware DSE sent out a painted unit. Although DSE's website shows a painted verrsion I think it is for advertisement puposes. I think from the pics posted here last week, I saw, the DSE unit it is unpainted. Wasn't martz unit out first?... Bye way thanks to all who have replied

[David Pozzi]

Martz was out first.
If you want to go around corners, get the DSE unit, the Martz isn't going to handle well.
Do a search on it and you will find more info.

There will be some other options in the near future.

[10Seconds]

Why is the Martz not going to handle well? Rick, what do you think about this? I am trying to figure out the rear suspension set up for my 1978 Trans Am and have seriously been looking at the Martz setup as it will let me keep my rear seat and trunk looking pretty stock (not really wanting a total 'race' setup).

Also, how much adjustiblity is there in the Martz system, it doesnt seem to have all the adjustments that others 4-links do.

And for 2nd gen's what other options are out there? I need a mini-tub capable system since I plan to run 315 to 335 (still debating it, I wanted to stay with a 17" rim and cant seem to find anything that fits that I want at the moment.)

[sinned]

The Martz 4-link is primarily a drag suspension system. It is very difficult to make a system design to launch a car for 60' handle well while turning (although not true vice-versa). Suspensions for drag style launches take nothing into consideration except how the design will affect A/S while designs that are intended to turn have a whole plethora of factors to be concerned with such as roll center height, side-view swing-arm length (a very big factor of anti-squat), and roll steer characteristics.



The biggest problem we as a PT community face lately is the sea of newcomers to the sport all looking for a quick, cheap and easy "fix". There are no quick fixes when it comes to 35 year old designs, they (GM, Ford, Chrysler) engineering didn't intend for these cars to go out and pull 1g even once, we are trying to get them to do that on a regular basis.

[rickk]

10 seconds , give me a call 214 908 2100 .i will tell you what i did to the back of my camaro .

rick kirkindall:ssst:

[73-TYPE-LT-LS1]

You can see picks of the Martz rear in my car by going to my website. I am planing on altering it at some point to a 3 link with a center bar off the top of the rear and extending the LCA's further forward making them longer. I will be trying different UCA's/LCA's though first. They will be using heims instead of solid ends. I think it would get more articulation using heims helping any bind issue.

When I do this, I plan to do it in such a form that will allow me to put it back to the semi 4-link style for drag racing. I don't know that I would call it a 4-link eith. It is much more like a ladder bar set up.

[David Pozzi]

Try making a mockup of the Martz and see the binding that happens if you move the "chassis" in roll. The 2 links on each side converge sharply, they will act like simple torque arms, but there is one on each side, so when the chassis rolls, one sides forward link ends go up, the other side goes down. This will attempt to twist the rear axle housing like it were an anti-roll bar. The housing is an extremely stiff antiroll bar, so the rear of the car will be super stiff in roll. If I remember right, the panhard bar is pretty high, this will raise the rear roll center and further increase rear roll stiffness. This is not the right way to build a good handling rear suspension. It would probably work on a drag only car.

DSE runs the links parallel or very close to parallel, they also have swivel ends on the links to prevent binding in roll. I don't know where they have the panhard bar, but I'm sure they know where it should be, which is usually close to level with the vertical center of the axle housing.

[Mean 69]

David, you are right about the Martz deal and the inherent mechanical bind, but this same condition exists in ALL four link systems, independent of the type of bushing used. The bind is mechanical, pure and simple. When you lift one end of the axle up (i.e. roll), one of the upper links "needs" to get longer, while the other one "needs" to get shorter. Period. If with a (any) four link setup, you replaced all of the bushings with rod ends, you would see clearly that this is the case, the darned thing wouldn't roll too easily if everything were perfectly rigid (frame, differential housing, links, etc). In the real world, these systems roll BECAUSE things are not perfectly rigid, the frame, differential, trailing arms, everything in the system will "give" in order to accomodate the roll.

One requirement of a trailing arm system is to have one set of arms relatively wide on the differential housing in order to have enough mechanical advtange to keep the axle perpendicular to the car's centerline. Almost always, it is the lower arms, which is fine, but it doesn't strictly need to be the case. When considering the "bind" on a four link-in-roll situation, you can improve things by moving the upper arms closer together, it is a pretty easy geometry deal to show that the effective length change in order to keep things happy (for the upper arms) decreases as the spread between them decreases. A typical drag race four link setup with the upper arms really wide, typically right above the lower arms in top view, would be the worst violator. A setup like DSE, where the upper arms are quite a bit closer in top (plan) view is better, better still is the Steeda setup for the late model Mustangs where the upper arms are really close together. What's best? Making both upper arms coincident, or in other words, making the "two" upper links into "one" upper link, effectively removing the redundancy. This is of course, a Three Link. Kinematically free, it does not mechanically resist roll, because it is not over-constrained like a four link setup. Fact.

Interestingly, the swivel end of the DSE links, which is pretty clever, has absolutely NO benefit in terms of the mechanical bind associated with the design of a four link. All is not lost though, they use rubber bushings, so the required length changes of the upper arms in roll are accomodated by compression in one side's bushings, and tension in the other side's bushings. So, the system rolls. Replacing with a stiffer poly bushing would create more resistance, not good.

The Panhard Bar appears to be right down the middle of the axle centerline, which basically means the static roll center height is right around 13" or so, depending upon the diameter of the tires used. Though their system doesn't offer much adjustment of the roll center height, there is a definite benefit for making it lower. It is true that the roll resitance would decrease, possibly requiring a stabilizer bar (small one), but lowering the roll center decreases weight jacking, which is a physical lifting of the rear of the car that is caused by a lateral force (cornering forces). A lower roll center will help keep the car planted in turns. This too, is fact.

Mark

[David Pozzi]

Mark,
Have you looked at a Chapman link rear suspension as used on a Lotus 7?
I don't remember what the top links were like but the lower link is a huge A arm two legs running forward and wide at the front, the rear of the A arm links meet under the diff center and attach to a bracket there. This A arm centers the rear axle and takes accel/deccel forces. I think there are two upper links one on each side off the top of the outer ends of the housing but it's been a long while since I looked at one of those cars. This setup is light, has a low RC and very simple. the rear housing attachment and A arm end must be very strong however to take much HP.
David

Here's a pic of it that illustrates housing failure due to twisting stress.

It seems to put a lot of stress on the housing, i'd guess the Lotus 7 housing is pretty thin. The length of the lower A arm should probably be longer. The nice thing about this setup is there is no panhard bar or structure for one.
https://static1.pt-content.com/images/pt/2005/10/lotus_s2rear-1.jpg

[Damn True]

Hmm, looks like an upside-down version of what is used on a Land Rover.

[Mean 69]

That setup looks a LOT like the Satchel type link setup, with the main difference being that the bottom link is one piece, on the Satchell it is two different pieces conneted to the housing with rod ends. It seems to be a pretty cool setup (Satchell, that is), I know of a guy that runs one on a C-Prep Jaguar and really likes the setup. Like you said, the roll center is really low, which is primarily a good thing, and the overall setup is really simple. Just like the Watt's approach on the Unique Performance T/A kit, the roll center height changes as the axle moves, my guess is that the 'Seven's suspension doesn't need to articulate too much though?

I'd guess that the torsion forces are handled pretty well by the housing, but I'd also agree with you, knowing how light those cars are, the thing must be pretty fragile and might not like a whole bunch more power. Those little Super Seven's really get things done on the track, I have never driven one, but the cult following they have seems to be pretty big. Very typically British, light weight, clever designs, works really well, but has a tendancy to break a lot!

Mark

[David Pozzi]

Most lotus stuff tends to break, the cars have no extra metal anywhere and very little reserve strength on any components.
I used to see some awsome super 7's autocrossing and they were legendary top time of day cars in the 70's.

[Q ship]

Wasn't Colin Chapman's credo that "the car should disintegrate as it crosses the finish line"? Build it just strong enough to finish with the least amount of weight.

[clinthart]

I am in the process of deciding on a 4-link for my 68 Camaro. I have been leaning toward DSE for the Qudra link but have seen the martz setup and started comparing. 1) The martz if a few hundred bucks cheaper, and 2) no mods to the back seat /floorpan. I am wondering if anyone has any specific advice or expirience with the martz setup? I will also be purchasing a minitub kit from martz or dse depending on overall qulity of the setup. :banghead:

In order for the Martz rear setup to fit, you have to cut into the trunk for the panhard bar/shock mount brace. You will also have to significantly modify your rear-end. So if you can't weld, you will need to account for the cost in getting the rear-end modified for the new 4-link. I put The Martz system in my car, and wish I hadn't.

Good luck.

[fletcherscustoms]

I like the looks of the DSE kit!! I plan to be using it my new project

[upacreek]

Martz was out first.
If you want to go around corners, get the DSE unit, the Martz isn't going to handle well.
Do a search on it and you will find more info.

There will be some other options in the near future.

David in your previos post you stated there might be other options
in the near future. Can you go into any details on that?
Thanks Gary

[73-TYPE-LT-LS1]

In order for the Martz rear setup to fit, you have to cut into the trunk for the panhard bar/shock mount brace.


I did not have to cut the floor at all for the shock brace http://www.73-ls1.com/rearsuspension.html

How ever, the floor is now cut as we are putting a 3-link in but using some of the Martz components (Shock brace, rear end brackets, sway bar, pan hard bar. Things that are getting changerd, front cross member is getting moved forward and will be running much longer control arms, adding a 3rd link and we cut the top square tube off the shock support to use round tube there to tie the back bars for the cage in to the chassis.

I should have pics up maybe next week if it all gets done by then. The cage is almost done (Back bars still need to be done), the front cross member is in place.

You can see some of the fron cross member here https://www.pro-touring.com/forum/showthread.php?t=13129

[clinthart]

I did not have to cut the floor at all for the shock brace http://www.73-ls1.com/rearsuspension.html

How ever, the floor is now cut as we are putting a 3-link in but using some of the Martz components (Shock brace, rear end brackets, sway bar, pan hard bar. Things that are getting changerd, front cross member is getting moved forward and will be running much longer control arms, adding a 3rd link and we cut the top square tube off the shock support to use round tube there to tie the back bars for the cage in to the chassis.

I should have pics up maybe next week if it all gets done by then. The cage is almost done (Back bars still need to be done), the front cross member is in place.

You can see some of the fron cross member here https://www.pro-touring.com/forum/showthread.php?t=13129

Perhaps the 73 is different than the first gen in the back half of the car. All I know is for the first gen you have to cut the trunk pan. The Martz website shows the same thing.

It isn't a big deal though. I didn't loose much at all. I have been hearing complaints from people about the suspension binding on them. I guess it is typical for this kind of setup (Martz or otherwise). I haven't gotten mine on the road yet, so I can't say for sure.