Endurance race 740 suspension

[rb92673]

Looking for advice for suspension for my 740 Lemons car. This car is 100% driven on track, never street. We had a race at Buttonwillow yesterday and I came to the conclusion that I have outgrown the existing setup. The car is very predictable and easy to drive, but it bounces around corners on the bump stops. I also get pretty bad front tire wear.

Current setup:
'85 740 Wagon - fully gutted and caged
300# springs w/ helpers on stock perch. Bilstein HDs up front
Relocated forward strut mount stud for max caster/camber
~200# cut springs from some Ford and stock KYBs in rear
IPD sway in front, none in rear
Lower bracing in front

I am pretty sure the answer is coilovers with koni race shocks from BNE, but I had a few questions before I fire the parts canon.

Are the shorter race inserts and cut tubes the way to go?
Do I need adjustable strut mounts as well?
Does the coilover setup and mounts provide enough camber for better tire wear, or do I need to extend the lower arms somehow?
Anything else I need?
Am I an idiot?

[JE Jr]

Hi if you dont have already, get the 2 small reinforcement bracketd on front crossmember from 960 95-98. That gives noticeable difference and a direct fit! Unfortunately I dont have any pics or so right now but someone else might have.

[JE Jr]

Also, wouldnt a 16mm anti sway in rear be nice to be able to run less rear spring rate to control rear body sway?

[Swedbrick]

The 960 braces are part numbers 9178665, 9178666. A strut brace will also do wonders.

Adding caster and camber can also be done by lengthening the lower strut rod, I'm at 400mm now, for 7 deg of caster and 2.2 deg of camber. That is with the strut top mod as well.

I run ipd springs with yellow koni dampers, still a bit of roll but it works, for track Ben's setup is more tunable for sure. The rear sway I found the 19mm to work well with my 25% lsd, the 25mm was way too stiff. I haven't tried the 16mm.

[Janspeed]

+1 on the strutt tower bridge/brace. Good mod. I have felt the difference on a 740 tarmac rallycar. The steering becomes instantly more precise.
Adjustable strutt mounts often use a heim joint whereas stock strutt mounts have a rubber bushing, The heim joints would take away sloppiness in the shock absorber action.
Another mod i want to highly recommend is to make/fabricate a 3rd engine mount between cylinder head and inner fender. This is meant to limit the axial movement of the engine block when going from on-throttle to off-throttle during shifts or while modulating the throttle in corners. Without it the axial movement of the engine upsets the front end during cornering which could induce understeer. The 3rd engine mount will also preserve the lower 2 engine mounts.

What the exact setup needs to be is also personal preference and how much grip the tires provide and how much flex the sidewalls of those tires give.
Maybe also have a look at the 740 racecar from Randy Pobst? You can see him race that car in videos on YouTube. His car seems to have pretty good grip.
And if there is anybody who can evaluate and tweek and set up a racecar suspension then he is the man.
https://youtu.be/E1IYhT-Z9gY

[Swedbrick]

Sam is actually the one maintaining Randy's car, he is here on the board as roadracer4life, so maybe he can provide some insight. The monthly online meets are also a good place to ask some questions;)

[blkaplan]

Originally Posted by rb92673

Are the shorter race inserts and cut tubes the way to go?
Do I need adjustable strut mounts as well?
Does the coilover setup and mounts provide enough camber for better tire wear, or do I need to extend the lower arms somehow?
Anything else I need?
Am I an idiot?

Yes to the first 2,

You should be able to get plenty adjustment within the confines of upper adjustment to get much better tirewear. At some point, if you go with too much negative camber you start trading cornering performance for braking performance.

Get as much of the 960 lower factory braces as possible. They all make a difference if you don't have them.

[rb92673]

Thanks for the replies everyone. I did reach out to Randy and Sam. Randy has Ben's full setup.

I ordered some roll correctors from Ben. Trying to figure out which way I want to go between Konis and Gaz.

Someone put heim joints on the front arms already, I will probably play with those once I get new coilovers. I will also look at the braces and strut mount.

[blkaplan]

Originally Posted by rb92673

Thanks for the replies everyone. I did reach out to Randy and Sam. Randy has Ben's full setup.

I ordered some roll correctors from Ben. Trying to figure out which way I want to go between Konis and Gaz.

Someone put heim joints on the front arms already, I will probably play with those once I get new coilovers. I will also look at the braces and strut mount.

We have Gaz if you want to go that route.

[rb92673]

Originally Posted by Swedbrick

The 960 braces are part numbers 9178665, 9178666. A strut brace will also do wonders.

It looks like one side of the braces are no longer available everywhere I search. Did these only come on 960s? Any special model?

I'll start keeping an eye out at local junkyards.

[blkaplan]

Originally Posted by rb92673

It looks like one side of the braces are no longer available everywhere I search. Did these only come on 960s? Any special model?

I'll start keeping an eye out at local junkyards.

all the 960s got the extra bracing because it got the big block.

You just need anything prefacelift because it changed... I might have the rear control arm side-side brace if you need one.

[rb92673]

Care package from Ben arrived. I feel like a cheatur now. Can't wait to install.

[JE Jr]

I would say the small but effective "960-braces" is a 95-98 only, but on all of these cars.
BR

[tintintin]

Photos of the mustache braces here:

http://forums.turbobricks.com/showthread.php?t=321101

BTW, I got mine at the JY.

[rb92673]

I was able to get the braces through a Wanted post.