Help with suspension setup for Sears Point this weekend

[brian52555]

Guys,

Looking for some insight from people that have run similar setups/spring rates.

My setup:

AST 4100 600fr/700r springs
Urethane everything
Toyo RA-1s
UUC Swaybar kit, from earlier when I only had H&R Sports/bilsteins


Question is this: I've heard about track guys disconnecting the rear sway bar, and just running a front cabrio sway. In fact, this week I disconnected my rear bar. Is this a reasonable idea considering the spring rates I'm running?

I've run Infineon once before, same suspension but with falken azenis though. Car felt tight, but I wasn't pushing it hard. Tires did get a little greasy in the hairpin at the end though.

I've run the car at various autocrosses with the same suspension and have pretty bad traction issues with the azenis. I think it's partly due to the suckiness of the tires, my sucky driving, and the fact that I was lifting the inside rear tire a bit due to excessive roll stiffness.

However, since I am now running way stickier tires, I've heard that you need more roll stiffness to account for that. So, I'm torn between putting the swaybar link back on or just running without it. I guess I'll find out on Saturday.

Thanks.

[SkiFree]

Brian --- Is this a SpecE30 car or something different?

I'd try with and without the bar to see which you like better. If you get enough racers together then you will have a variety of responses in regards to the removing/keeping the sway bar. IN GENERAL I've had customers remove the sway bar for tighter circuits or autocross and then put them back on for longer, more sweeping tracks.

[M-technik-3]

AST are not spec legal so thinking it's a DE car. How many sessions are you doing? You could try it both ways and see what you like better.

[Wh33lhop]

Yeah if he had ASTs he would be booted out of Spec pretty fast ;)

I'll agree with the others, it may depend on the track--so try it both ways. It is very easy to just remove one endlink, and that's all that's necessary. The UUC kits are adjustable, too, so in the event that you think in between would be better, you could always try to soften it up by moving the endlinks towards the front of the car.

Congrats on an awesome setup btw, I am on GCs and UUC sways right now and it is great; at some point in the future I'll get my paws on some ASTs.

[SkiFree]

Ah, I must have skipped right over that....

Just about any non-specE30 sway bar set should be adjustable.

[brian52555]

Yep, just HPDE guys.

I had the UUC bars set on the softest already, and I was still having traction issues at the autox cross.

I'll probably just bring my jack/stands to the track and run the bar in the afternoon sessions. Running both Saturday and Sunday so I'll have ample time to adjust.

Main concern is from the extra grip from the r comps, haven't even driven them fully warmed up yet.

[gverelli]

I removed the rear bar and the car feels great, being able to get on the gas MUCH earlier than having my previous 16mm bar in there. I wouldnt even consider putting it back in. My rear is 850lbs though, just unbolt one endlink (5mins) and see if you like the difference.

[brian52555]

Thanks, how is the rest of your car set up? Tires, shocks, etc.

[gverelli]

Thanks, how is the rest of your car set up? Tires, shocks, etc.

550lbf/850r w/Koni adjustable. Note: I do raise the rebound of the rear shocks quite abit for track.
225/45/15 Hankook RS3 (Cold Tire Pressure 34f/36r) Still have not figured out a proper balance...
20mm adjuatble front bar on stiffest with m3 links.

[bmwguy325is]

AS mentioned above with the 850 rear springs. This is common for guys running no rear bar. I have seen guys run 1000lbs springs with no bar. What you may want to do is leave the rear bar on and stiffen the front bar. It may ad a lil under steer but nothing Im sure you cant drive around.

[F34R]

I had a chat once with a fellow racer from Tree house racing, I asked about sways to run etc. He told me no rear sway is best for autox type racing.

[brian52555]

Sooo, I thought I would update this thread to let you guys know how I did.

The car held up great, suspension felt great. A little too much body roll for my tastes in the rear, but the car was very neutral and controlled. I never really got to the point where I was on the ragged edge of traction (225 RA-1s) since I was in HPDE 1, but I came pretty close and there were no bad habits that I could detect. I should have reconnected the rear sway bar for the Sunday session but ran out of time.

I think I might compromise and throw the original 325is rear sway back on.

Also, I lost all tire pressure in my front right tire between turns 2 and 4 on Sunday. Last lap, during run 3 of 4. That ended my day... it was ok I was just happy to have a spare street tire so that i could drive home. Oh, and I got signed off to HPDE 2 so I can drive solo from now on... might just retain an instructor for one or two more track days though. Plenty to learn at infineon.

I also rode in my instructor's caterham 7. Holy shit... 200hp, 1200lb w/o driver. Thought I was going to die.