I went to Buttonwillow on March 29th and my car felt twitchy and/or slightly unstable upon corner exit as I accelerated. I honestly felt that the car was reacting to every bump in the track and it made me feel like I could lose it at any moment. It was usually under acceleration that I felt as if the car felt really squirrelly.

Last time I went out there I got a 2:15.904 and this time around I only got a 2:18. The things I changed/added to my car after the last time out there are the exhaust, seat and rail, krank vents, catch can, radiator plate, corner balancing, .5 degrees camber front and rear and a little more toe in front and rear.

Here's a list of my mods:
Tein SRC coilovers (10 clicks front and rear)
ST front and rear Sways
TC Design Rear AntiBumpsteer Kit
CarboTech brake pads: XP10s front, XP8s in rear
StopTech Slotted rotors front and rear
StopTech SS Brake Lines front and rear
Motul RBF 600 fluid for brakes and clutch
Enkei RPF1s 17x9 +45 front and rear (fenders rolled/pulled/lightly flared to fit these)
Bridgestone RE01R 245/4017 front and rear
Alignment and corner-balancing done by WestEnd
My Alignment settings are as follows:
Front Specs:
2.5 degrees camber
6.0 caster degrees on left/6.5 caster degrees on right
toe in total: 1/16 inches
Rear Specs:
3.0 degrees camber
toe in total 3/16

When Darrin at WestEnd set up my car this way, he told me that the car would have faster turn-in and be more stable but now I'm second guessing that. What do you guys think about my setup and what do you suggest I change and/or add to increase stability?

Here's a pic of my car for good measure:


Thanks in advance.

 

I am guessing because you are not running the big ass wing, the front camber maybe a little too aggressive for your non stagger tire. You may have way too much grip in the front.

 

you mentioned this was your 3rd time at bw, did it feel better the previous times with the same setup?

if so, perhaps you tire pressure is too high in the rear...

 

I'm thinking the radiator plate cost you at least 2 seconds! I am sure those guys running similar setups have a better idea, but the combination of high spring rates and street tires probably have a lot to do with the twitchiness. Try softening up the car all around, especially in the rear.

 

I would adjust your dampers.....Losen up the rear a bit and/or tighten up the front. Also tire pressures. Why are you running toe in in the front

if you want better turn it then you need toe out in the front. I dont think that is your problem but just wondering.

Agree with above.......those Coilovers are better suited with R comps than street tires.

 

Camber seems a little odd, with the rear being more than the front. -3 is a bit much I would think for street tires. I run 2.7 in the racecar and it's on dot R. FYI I run almost the same spring rates as the SRC's but with no rear swaybar. Hint Hint.

Bill

 

I doubt is was the lack of a wing because I was going faster last time and the car didn't feel a lot more stable.

I'm going to try softening up the rear.

 

Last time I was there I got a faster time but I had .5 degrees less camber front and rear with less toe-in front and rear as well. My car wasn't corner-balanced either.
The reason I went with this much camber is because last time I was there, I was actually running on about 1/4" of my sidewall.
I'll pay attention to my tire pressure next time. The day got pretty hot and when I went to the tire shop, my tire pressures were at about 38psi front all around after starting the day at 33psi all around.

tinkfist: Like I said earlier, my car felt a lot more stable last time and actually inspired enough confidence to maintain higher speeds throughout most of the corners. I'll definitely soften up the rear next time around.

Turn-R-Us: I'm running this much toe-in because Darrin at WestEnd suggested this would help me be faster on track.

blackey: I'm starting to think that the toe-in was a bad idea. I honestly think the camber helped as I was using the whole tire during my sessions. That's something I really paid attention to as I was riding on my sidewall last time I was there.


-What are your recommendations on alignment for a non-staggered setup?
-How should I adjust my tire pressures and rebound and compression?
-I spoke to some guys at the track and they told me that perhaps I'm getting overwhelmed by the feedback from the bucket seat. Any of you guys ever experience that?

 

Sounds like it's too stiff -- remember that being too stiff isn't a good thing as the tires just skip / hop over every little bump instead of absorbing them. That would lower your grip levels under acceleration as it tries to jump out of your hands.

 

i don't think your alignment made the rear end more twitych.

it seems that that's the only thing that changed from last time, which you said felt stable.

were you running the same brand of tires?

you should definitely take pressure readings when you're at the track to see how high they are getting. also, different tires have different optimal "hot" psi.

sure, you can change the suspension settings, but if those were the same as last time, i don't see how it contributed to causing a new problem.