Black magic in the art of suspension for a 1966 fairlane

[QuarterD25]

I am starting this thread because of Matt's "let's talk arb" thread. In an attempt to not derail his thread anymore, I am starting this new one. Ron had asked a couple of questions about my set up.
A basic run down first. I have a 1966 fairlane/289/t-5.

I have the street or track, http://www.streetortrack.com/Street-or-Track-Front-Coilover-System-pr-24491.html , for the front set up. I started out with the sport shock. After letting a much better driver/builder critique my car. He made the suggestion that I needed about 3x more low speed rebound. When going through the slaloms, the car would roll to the outside but not turn. The explanation as I remember was that the tires were turning but they still went strait. Therefore I picked up the race coils/shocks. Since then, the car handles much better overall. I am thinking about getting my "sport shocks" set to even stiffer setting than my "race shocks". I am not sure of the current spring rate but the previous was 450 lbs. I am also running the 1 1/8 sway bar.
For the rear, I have the maier 200 lbs leaf springs and panhard bar set up.

A. I have to work out the Spindle KPI/SAI with the length of the A-arms, tire width & wheel backspacing ... to end up with a desirable scrub radius.

I did my best to measure everything and/or scour the internet. For the lengths: UCA 9 3/4 "; LCA 16 1/2.
Measuring the KPI was a bit difficult in that the car is still put together. I am currently using a late 60's mustang drum spindle. I measured on the face of the hub, 89.7* and using a ruler/digital degree finder got 81.5. Searching over at cc.com resulted in someone else measuring the kpi @ 7.913 for the disc spindle. I cant imagine they would be that different.
I am running a 17x8 w 28mm off set in the front and 17x9 w 42mm offset. I have NTO5 235/40 & 255/40 for the tires.

B. Once I know the spindle KPI/SAI, that guides me on how much caster I need to build in to achieve a KPI/Caster Split favoring the caster.

From my last know alignment, they where able to get -2* camber and 1* caster. For some reason, I remember it being much more for both.

C. I need to work out if we want caster gain, or for the caster to stay the same, as the front suspension compresses fully under braking & turning (called "Dive")

D. If I can get the caster I want ... statically and/or with gain ... so the KPI/Caster Split favors the caster ... I can run less Camber, which is the goal. We're always going to run some static camber (neg). But if I can not get more caster than KPI, I will need more camber.
E. Once I know how much camber I need for that combo, I work out how much of it is going to be static camber & how much is going to be camber gain.
F. How we get the camber gain, & how much, affects the car's static & dynamic roll center ... so they have to work as a team too.

A couple of final notes. I was on a rampage with my digital angle finder and metal ruler. While I had it on the stands with the wheels off today I measure the face of the hub (left side) centered 89.2*, right 88.6*, and left 00.88*. I am not sure what this means or could elude to but I am sure someone will. From ball joint to ball joint on the spindle was about 7 1/2 inches. Right now the UCA has a 9* incline while the car is on the ground.

If there is anything I missed please let me know and I will do my best.

[Tomswheels]

Tyler, I am willing to donate, until Ron chimes in with tangible advice, the Baseball bat I used on the Barracuda fender lips....

[Ron Sutton]

Tyler, I am willing to donate, until Ron chimes in with tangible advice, the Baseball bat I used on the Barracuda fender lips....

Tom,

I don't care who you are ... that's funny right there. :lol:

Tom ... I love your car. Some guys have a hard time figuring out why it works well in AutoX, but I get the high Roll Angle setup for tight corners.

----------------------------------

QuarterD25 ... I'd rather call you by your real name ... unless it is QuarterD25. :lol:

I'm doing some research on your suspension to understand how much caster adjustability it has, because +1.0 degree of caster is just ugly to work with.

I'll be back to post when I have some info ...

[Rod]

Tom,

I don't care who you are ...

NO.... now that's funny right there!!! :cheers:

[QuarterD25]

Quarterd25 is a mix of nickname and internet alias.
Ron, I think I could get more caster if messed with the fender. It comes pretty close to the front lower portion. That or I could borrow a bat and threaten my car to do what I want....

[Ron Sutton]

Quarterd25 is a mix of nickname and internet alias.
Ron, I think I could get more caster if messed with the fender. It comes pretty close to the front lower portion. That or I could borrow a bat and threaten my car to do what I want....

Tom will loan you the bat. It has worked well for his hot rod. :)

[Ron Sutton]

Ok, I got some info from your front suspension Mfg.

Shaun & ST built a 70 Mustang with that same system and has it set at +6 degrees caster. He says, "Don't shorten the strut rod too much as it'll pull the tire forward in the wheel well and visually look goofy. Lengthen the forward heim, shorten the rear and/or shim the front UCA bolt, all will add caster. Use the strut rods for final tweaking. Ideally you want the LCA's perpendicular to the frame rails."


I would say that's your starting point. Get all the caster you can, without pushing the wheel too far forward. We'll make the rest up with caster gain, camber gain & static camber.

Once that is done & the car is on the ground at ride height, figure out 4 angles for our discussion.
1. Upper A-arm angle parallel with the car.
2. Upper A-arm angle perpendicular to the car.
3. Lower A-arm angle perpendicular with the car.
4. Lower Strut Rod, along it's length.

This will help me to see what you're working with as far as A-arm angles ... and allow us to discuss caster gain & camber gain options.

And POST PHOTOS. :)

[Ron Sutton]

I have the street or track, http://www.streetortrack.com/Street-or-Track-Front-Coilover-System-pr-24491.html , for the front set up.
That is where the caster info came from.

I started out with the sport shock. After letting a much better driver/builder critique my car. He made the suggestion that I needed about 3x more low speed rebound. When going through the slaloms, the car would roll to the outside but not turn. The explanation as I remember was that the tires were turning but they still went strait. Therefore I picked up the race coils/shocks. Since then, the car handles much better overall. I am thinking about getting my "sport shocks" set to even stiffer setting than my "race shocks".
You're on the right track here.

I am not sure of the current spring rate but the previous was 450 lbs.
Please find out the current spring rate.

I am also running the 1 1/8 sway bar.
Cool.

For the rear, I have the Maier 200 lbs leaf springs and panhard bar set up.
Very cool. No spring bind that way.

I did my best to measure everything and/or scour the internet. For the lengths: UCA 9 3/4 "; LCA 16 1/2.
Helpful.


Measuring the KPI was a bit difficult in that the car is still put together. I am currently using a late 60's mustang drum spindle. I measured on the face of the hub, 89.7* and using a ruler/digital degree finder got 81.5. Searching over at cc.com resulted in someone else measuring the kpi @ 7.913 for the disc spindle. I cant imagine they would be that different.
A lot of Ford passenger cars utilize 8 degree KPI, so let's use that #.


I am running a 17x8 w 28mm off set in the front and 17x9 w 42mm offset. I have NTO5 235/40 & 255/40 for the tires.
Ok, so the tires are not the same. The difference is 8.5% less tread in the front. Is it your plan to keep these sizes?


A couple of final notes. I was on a rampage with my digital angle finder and metal ruler. While I had it on the stands with the wheels off today I measure the face of the hub (left side) centered 89.2*, right 88.6*, and left 00.88*. I am not sure what this means or could elude to but I am sure someone will.
I'm not clear on what you're measuring here. Can you post photos ?

From ball joint to ball joint on the spindle was about 7 1/2 inches. Right now the UCA has a 9* incline while the car is on the ground.
OK.

[Tomswheels]

Tom,

I don't care who you are ... that's funny right there. :lol:

Tom ... I love your car. Some guys have a hard time figuring out why it works well in AutoX, but I get the high Roll Angle setup for tight corners.

Thanks Ron, unfortunately High roll angle on the Barracuda, and on myself actually, was not by design :banghead:



QuarterD25 ... I'd rather call you by your real name ... unless it is QuarterD25. :lol:
.

Ron, you can call him Tyler, or call him by his Native American nickname: "Tires too Small"...

[QuarterD25]

Ron,
A couple of questions and comments.

-Ok, so the tires are not the same. The difference is 8.5% less tread in the front. Is it your plan to keep these sizes?
My tire size is not set. I am not sure if i can fit anything more in the front with my current alignment though.

For the LCA, it has a sort of J-shape to it. Should the long side be parallel to the ground or should the two mounting points be parallel to the ground?

I also weighed the corners a while ago on my car. I had about 6 gals of gas in the back at the time. With out me the car was 3127; FL 928, FR 855, RL 650, RR 696. With me 3337; FL 1007, FR 887, RL 730, RR 715. I have since adjusted the front right spring down so that side doesn't sit so high. I also moved the battery from the front right to the back right.

I will work on getting pictures for you tomorrow.

[Ron Sutton]

Ron,
A couple of questions and comments.

-Ok, so the tires are not the same. The difference is 8.5% less tread in the front. Is it your plan to keep these sizes?
My tire size is not set. I am not sure if i can fit anything more in the front with my current alignment though.
If you can not fit any more in the front ... I would not go wider in the rear. I was just asking so I knew your final plan.


For the LCA, it has a sort of J-shape to it. Should the long side be parallel to the ground or should the two mounting points be parallel to the ground?
Contact S&T.


I also weighed the corners a while ago on my car. I had about 6 gals of gas in the back at the time. With out me the car was 3127; FL 928, FR 855, RL 650, RR 696. With me 3337; FL 1007, FR 887, RL 730, RR 715. I have since adjusted the front right spring down so that side doesn't sit so high. I also moved the battery from the front right to the back right.
You always want to work with weights that include you in the car, ready to AutoX. What are the weights now?


I will work on getting pictures for you tomorrow.

Okie dokie

[QuarterD25]

Gentlemen,
Sorry about taking so long.
Ron I started taking different measurements and I never realized how hard that could be. It seemed like I could never get a consistant number. It also did not help that I only have a slanted drive way. So I took a bunch of pictures to put up and hopefully help the internet engineers decipher my recordings. So here we go.
Drive way: about 2 degrees
Frame of car: 1.10 *
Upper A arm;
perpendicular: 8* (on upper arm); 19.1 (on top of the ball joint)
parralell: 4.10 (on cross bar); 3.4 (on the A arm brace)

Lower arm: 4.3 (measured on top of where the strut mounts to the arm)
Strut length: 14 1/2"

Some additional info. With my race tires (245/40/17) I have a 2" gap between the fender and the front tire and 3" in the back. I did my last alignment with my street tires (225/50017).
Also, my front spring rate is about 600 lbs.

[QuarterD25]

https://static1.pt-content.com/images/pt/2013/07/9219010462_7fd7fc571e-1.jpg (http://www.flickr.com/photos/24728318@N08/9219010462/)
Untitled (http://www.flickr.com/photos/24728318@N08/9219010462/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr

[QuarterD25]

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Untitled (http://www.flickr.com/photos/24728318@N08/9219002414/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr

https://static1.pt-content.com/images/pt/2013/07/9216226353_0dcb3b4237-1.jpg (http://www.flickr.com/photos/24728318@N08/9216226353/)
Untitled (http://www.flickr.com/photos/24728318@N08/9216226353/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr

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Untitled (http://www.flickr.com/photos/24728318@N08/9218997446/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr

https://static1.pt-content.com/images/pt/2013/07/9218994870_558ebfc8f1-1.jpg (http://www.flickr.com/photos/24728318@N08/9218994870/)
Untitled (http://www.flickr.com/photos/24728318@N08/9218994870/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr

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1966 fairlane (http://www.flickr.com/photos/24728318@N08/8426411591/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr

[Ron Sutton]

The photos help.

That driveway looks way steeper than 2 degrees. This won't affect your side to side angles, but the front to back angles are not going to be accurate. Do you have a way to check the angle of the front frame on level ground ... so we can compare it to the 1.20 degrees you captured here in the driveway?

[Ron Sutton]

Gentlemen,
Sorry about taking so long.
Ron I started taking different measurements and I never realized how hard that could be. It seemed like I could never get a consistant number. It also did not help that I only have a slanted drive way. So I took a bunch of pictures to put up and hopefully help the internet engineers decipher my recordings. So here we go.
Drive way: about 2 degrees
Frame of car: 1.10 *
Upper A arm;
perpendicular: 8* (on upper arm); 19.1 (on top of the ball joint)
parralell: 4.10 (on cross bar); 3.4 (on the A arm brace)

Lower arm: 4.3 (measured on top of where the strut mounts to the arm)
Strut length: 14 1/2"

Some additional info. With my race tires (245/40/17) I have a 2" gap between the fender and the front tire and 3" in the back. I did my last alignment with my street tires (225/50017).
Also, my front spring rate is about 600 lbs.

Again, driveway looks WAY steeper than 2 degrees, so we need a more accurate reference. Refer to post above.

I like the UCA angle from BJ to shaft. Should provide good camber gain.

You said the UCA parallel angle is 4.10 degrees (at the shaft) ... but i don't trust that number, until we get an accurate reference point. Do you have a way to check the angle of the front frame on level ground ... so we can compare it to the 1.10 or 1.20 degrees you captured here in the driveway?

I can not see your LCA very well. It actually looks lik eyou have the angle gauge on the strut rod & not the LCA. Am I seeing that correct? Regardless, what is the angle of the LCA? ... and just to confirm ... is it running downhill OUT from the frame to the ball joint?


Hmmm. 600# front springs. When did you put these in? Was it at the same time of the S&T install ... or later after driving it some?

[Bryce]

Tyler,

Let me know if you want to swing by my place and I can help out with measurements.

We also have similar suspensions, except I built mine with a little more adjustment capabilities. I only have a 1* loss in camber at max steering angle, what does yours have?

600 seams like a really high spring rate? I am running 400 with a 1.25" splined bar. My motion ratio is .86 whats yours? I think its similar.

[Ron Sutton]

Hey Guys,

I'm on the Forum today for a few more hours ... then I'll be gone for a week.


I'm meeting up with my friend Neil Porter at Sears Point where he's running 2 formula cars in SCCA racing.

78694



Then I'm camping with my girls the rest of the week.

78695



I'll be back online late Thursday (7/11) or Friday morning (7/18).

[Bryce]

Tyler,

If you make it over sometime we can talk about removing bumpsteer or making work for you!

[QuarterD25]

Again, driveway looks WAY steeper than 2 degrees, so we need a more accurate reference. Refer to post above.

I like the UCA angle from BJ to shaft. Should provide good camber gain.

You said the UCA parallel angle is 4.10 degrees (at the shaft) ... but i don't trust that number, until we get an accurate reference point. Do you have a way to check the angle of the front frame on level ground ... so we can compare it to the 1.10 or 1.20 degrees you captured here in the driveway?

Ok, so I tried a differnt/pretty level drive way. UCA parallel is 2.5* on the brace for the A-arm; 2.9* on the cross shaft

I can not see your LCA very well. It actually looks like you have the angle gauge on the strut rod & not the LCA. Am I seeing that correct? Regardless, what is the angle of the LCA? ... and just to confirm ... is it running downhill OUT from the frame to the ball joint?

I remeasured and took some better pictures. The original one is on top of where the strut mounts, it seemed to be the flattest part. I remeasured that and got 4.4*. I also measured on the LCA and got around 3.8*. It was hard to get a consistent measurement.

Hmmm. 600# front springs. When did you put these in? Was it at the same time of the S&T install ... or later after driving it some?

I put the 600# springs after driving with the 450# for awhile. I did that due to a recommendation that my shocks did not have enough low speed rebound. The 600# springs are matched to the stiffer shock from S&T. It definitely made a huge difference in every way. The car responded much quicker and rode much better after the install.

[QuarterD25]

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Untitled (http://www.flickr.com/photos/24728318@N08/9220993852/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr
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Untitled (http://www.flickr.com/photos/24728318@N08/9220995548/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr https://static1.pt-content.com/images/pt/2013/07/9220991862_114693e297-1.jpg (http://www.flickr.com/photos/24728318@N08/9220991862/)
Untitled (http://www.flickr.com/photos/24728318@N08/9220991862/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr https://static1.pt-content.com/images/pt/2013/07/9220990210_7a1501438c-1.jpg (http://www.flickr.com/photos/24728318@N08/9220990210/)
Untitled (http://www.flickr.com/photos/24728318@N08/9220990210/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr https://static1.pt-content.com/images/pt/2013/07/9220987912_ecdc0eecc7-1.jpg (http://www.flickr.com/photos/24728318@N08/9220987912/)
Untitled (http://www.flickr.com/photos/24728318@N08/9220987912/) by quarterduck25 (http://www.flickr.com/people/24728318@N08/), on Flickr

[QuarterD25]

Bryce,
I leave for Virginia Saturday night. Ill have to hit you up when I get back. I'm not going to lie...I have no idea what my camber loss is or what my motion ratio is....let alone how to calculate either one.

[Bryce]

Bryce,
I leave for Virginia Saturday night. Ill have to hit you up when I get back. I'm not going to lie...I have no idea what my camber loss is or what my motion ratio is....let alone how to calculate either one.

Don't worry next weekend I will be dialing in my car for the 21st, bring your car over and I will help. Both are easy to calculate and measure.

[QuarterD25]

I won't be back untill the 26th. Ill have to hit you up when I get back.

[Maier Motorsports]

Hey there guys. I think I know that guy that drove your car. He's full of hot air... I definitely have spent a ton of time looking over tiny things on my cars and it always good to have more info. I remember trying to read my first chassis dynamics book around the age of 14 and I was lost. I then went into real world screwing things up and learning first hand why you don't do things. I think the way I would go with that beast of a car would be exactly what you were thinking about.. Keep revalving until you not happy anymore. This will get the car to respond and then it will start to chatter or skate. upping the spring is more of an undertone. If you up the spring the car will feel more responsive but at a cost. It will start to understeer mid corner then pick up a loose off feel. Moral to the story is try things out, feel them, get friendly with your car and learn what it likes and does not like. Also, drive other cars and learn to recognize good and bad characteristics and try to replicate the good on your car. This is the long road but you will learn a ton from it. The geometry thing is huge as well. I am defiantly not discrediting need for this info, however get the feel down and research the geometry at the same time for coffee reading. Good luck young Walker and use the Force.

[QuarterD25]

Hey there guys. I think I know that guy that drove your car. He's full of hot air... I definitely have spent a ton of time looking over tiny things on my cars and it always good to have more info. I remember trying to read my first chassis dynamics book around the age of 14 and I was lost. I then went into real world screwing things up and learning first hand why you don't do things. I think the way I would go with that beast of a car would be exactly what you were thinking about.. Keep revalving until you not happy anymore. This will get the car to respond and then it will start to chatter or skate. upping the spring is more of an undertone. If you up the spring the car will feel more responsive but at a cost. It will start to understeer mid corner then pick up a loose off feel. Moral to the story is try things out, feel them, get friendly with your car and learn what it likes and does not like. Also, drive other cars and learn to recognize good and bad characteristics and try to replicate the good on your car. This is the long road but you will learn a ton from it. The geometry thing is huge as well. I am defiantly not discrediting need for this info, however get the feel down and research the geometry at the same time for coffee reading. Good luck young Walker and use the Force.

Mike its good to hear from you. I dont know about hot air but definitely good advice. I've started to dig in to Carrol Smith's books and trying to find out anything I can on the old trans-am cars. I would love to find some info on the holman-moody cars. Either way, there is a steep learning curve. I took your recommendation on the shocks and they are a definite improvement. When you talk about "upping the spring as an undertone", what do you mean by that?
The next one is going to be getting a 9" with some different gears. I saw that you got the speed way rear, is the floating axles a requirement or just a nice to have?

Either way, thanks for the advice again.

[Ron Sutton]

Hey there guys. I think I know that guy that drove your car. He's full of hot air... I definitely have spent a ton of time looking over tiny things on my cars and it always good to have more info. I remember trying to read my first chassis dynamics book around the age of 14 and I was lost. I then went into real world screwing things up and learning first hand why you don't do things. I think the way I would go with that beast of a car would be exactly what you were thinking about.. Keep revalving until you not happy anymore. This will get the car to respond and then it will start to chatter or skate. upping the spring is more of an undertone. If you up the spring the car will feel more responsive but at a cost. It will start to understeer mid corner then pick up a loose off feel. Moral to the story is try things out, feel them, get friendly with your car and learn what it likes and does not like. Also, drive other cars and learn to recognize good and bad characteristics and try to replicate the good on your car. This is the long road but you will learn a ton from it. The geometry thing is huge as well. I am defiantly not discrediting need for this info, however get the feel down and research the geometry at the same time for coffee reading. Good luck young Walker and use the Force.

Oh Mike ... you are both funny & helpful.

If anyone didn't catch Mike's sarcasm in the first line, Mike is the guy that drove Tyler's car & gave him advice on shock valving.

[Maier Motorsports]

Undertone... Well maybe I understated the need for attention to springs. I learned the most about springs when I was racing against Ron Sutton with the midgets. I also learned that I need to learn a whole lot more about springs. There is a lot to be gained from refining this part of your car. I have tried the big spring-small bar and small spring-big bar styles and It can drive you crazy. I read the Mark Donohue book "The Unfair Advantage" and this book really struck a cord with me on springs and bars. I have leaned towards going as soft as I can in the front with out compromising rear brake bias. When you go too soft,the nose will dive too far,and the rear will lighten up, then you will experience premature brake lock up. You do not want to reduce rear brake because you will then start to over work the front tires, not to mention you won't stop as fast. The car will now be pretty floppy with a soft spring so now is the time to bar up the front until the car picks up a mid corner push. Then back off the bushings a bit on the end links. The end links adjust remarkably well. From this point,we start to tune the shocks to give you the "bio feedback " you want. This it where the black magic comes in. Shocks have specific things they do for sure but they all very because each person likes a little different feel. So this is why it takes some time to tune a car and why you always see me cranking on the car. Once again, have fun. Mike