302S setup inquiry

[ajaquilante]

To me, 600/350 is very stiff and is going to understeer significantly on the 660/680 Pirellis. The 680 square will help, but not solve all. I think 450-500F/300R would work well and should not bottom out at Laguna/Sonoma. Any softer and you might bottom out the shocks. I don't know the Dynamics well enough to get too extreme.

 

[steveespo]

I like AJ’s input but remember to factor in race weight. His spring package may work well on a 3400 lb all up car but our cars are between 3600-3800 lbs on track and may need a little more rate to prevent bottoming. I ran 575/375 spread on a 3740 lb track weight car.


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[ajaquilante]

Looking at his original post its a 302S, so I would think its 3500lb or so w/ driver. I could be wrong though. Also a difference of 200lbs would not bother me. Burning off a tank of fuel is 100 lbs.

 

[Mad Hatter]

Here I am with 600/350 springs for a 80% track/ 20% street car weighing 3500 lbs with me in it...... Does that mean I could get more grip from going down to 500/300 and be more comfortable???

 

[Fabman]

Here I am with 600/350 springs for a 80% track/ 20% street car weighing 3500 lbs with me in it...... Does that mean I could get more grip from going down to 500/300 and be more comfortable???

Mine likes the 500's better and I'm going from 325's to 300's out back.

 

[ajaquilante]

The 500/300 works pretty good as a base line on these car. Its what we used to run on the T2 cars before they opened the rates up.

 

[DocB]

With the 500 lb. springs on the front, did you experience, or feel that you had excessive break dive?

 

[ajaquilante]

At 500, IMO, no.

 

[DocB]

AJ, thanks for your input.
You previously stated that 500 on the fronts works pretty well as a baseline, and that is what you used to run before they opened the rates up.
I am assuming that, because you were allowed to, you bumped up the rates a little? (especially on the fronts?)
If so, why?

 

[ajaquilante]

I say 500 because that should work with most front bar(like the FRPP blue bar) and shock setups without bottoming the shock/chassis on high vertical load tracks. We didn't bump the rates up, we have gone softer. It was all about making the tires last.

 

[Mad Hatter]

This thread has turned my suspension goals all upside down.... and just recently, I got in touch with a rather nuts and well known stock car racer from the 80's here in Chile. And after going over my car he said.... Why the #@%$& ... do you have such a stiff spring rates..... Translated and edited from spanish (...and lots of swearing)

 

[Fabman]

This thread has turned my suspension goals all upside down.... and just recently, I got in touch with a rather nuts and well known stock car racer from the 80's here in Chile. And after going over my car he said.... Why the #@%$& ... do you have such a stiff spring rates..... Translated and edited from spanish (...and lots of swearing)

Gotta watch out for us crazy old stock car guys.

 

[Mad Hatter]

Gotta watch out for us crazy old stock car guys.

Yup.... he reminded me of your earlier posts..... he used to known as Loco Ramirez... and won many races here in Chile as well as Argentina.

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[ajaquilante]

Here is a general thought I apply to this: Unless you have some huge splitter, monster rear wing, a flat or tunneled floor, who cares if the car is moving around. These are not 1200lb formula cars that do everything "right" and are aero sensitive. They are street cars turned racecars that have compromises. So maybe we give up a few lbs of downforce, but we gain tire life and mechanical grip. The only catch is that some people don't feel as comfortable running a car in that fashion. It took some time getting used to popping the inside front wheel off the ground.

The nature of most track-days is that with restricted passing, or "expanded with a point-by" you are at the mercy of traffic. How many fast laps do you get per session? When we run days at NJMP or other tracks, rarely do we get "clean sessions" when there are more than 15 cars on track. So you get some fast laps every once in a while, but that masks consistency or a lack of consistency while dealing with traffic. An example was when CTSC went from the spec AST shock to open shocks, the ultimate laptimes didn't drop significantly, but the consistency of the cars took a huge step forward. The hard part is learning this as usually it takes competition to drive the desire to experiment and see what works to go faster to beat the best.

 

[treynor]

Thank you all, this thread has been very helpful. We're getting ready for testing next weekend, and I'm going to try 680 square slicks (as well as square Hoosiers as an alternate) and, if we can get them in time, some 500 / 300 springs.

A question on sway bars. According to my (original) tech, my car was delivered with a 35mm front / 13mm rear sway bar. The 302S owners' manual says it has a 35mm front / 22mm rear (!) which may reflect an update for later years. And I currently have a 35mm front / 17mm rear. I'm curious what if any suggestions folks have for either stiffer or softer springs?

 

[blacksheep-1]

use the 13mm bar

 

[Mad Hatter]

I was wondering if those spring rates apply to a SLA or regular front suspension? Talking to Filip at Cortex and he suggested a #900 front spring with the SLA.

 

[Grant 302]

I was wondering if those spring rates apply to a SLA or regular front suspension? Talking to Filip at Cortex and he suggested a #900 front spring with the SLA.

Totally different wheel rate for SLA. Needs to be higher since mounted more inboard.

 

[Mad Hatter]

that makes sense...

 

[Mad Hatter]

Just checkin... but the Rolex world challenge cars run with McPherson struts then?? I have a goal to have that outside front wheel in the air,,, but still not there yet....