I recently finished the suspension work on my car and took it to autocross this last weekend. I was slow but did not DNF any of my runs. I ran it on my street tires (Yokohama AVS Sports) but I do have Hoosier autocross tires on my stock wheels that I will use from now on.

My current setup is D2 coilovers, stillen RSB, front STB, all ES bushings and motor mounts, Brembo slotted/cross-driller rotors, porterfield R4S pads and Technafit brake lines.

It understeered like mad. Suggestions please.

 

brake earlier, do not brake into turns, accelerate thru turns, slow in fast out is the best way to drive a heavy FWD car in autocross, my car turns better while its accelerating, but it is a 3rd gen with more weight in front

also set rear shocks at full stiff and fronts at half stiff

 

You might want to adjust that stillen RSB to be a little more aggressive too.

 

What about disconnecting the front sway bar?

 

What are your tire pressures??? Make adjustments there as well. Too high, tires will skate, too low, tires will roll over

 

What gdmaxse say is right. But other stuff you might check is you alignment. The stock alignment is 0 to -1 deg camber in front with 0 toe and the rear beam is -.5 to -1.1 camber in the rear.

Currently my car is setup to turn.
-2.5 deg camber in front with 1/8" toe out. The rear is -1.1 camber.
shocks are set to half in front full in rear.
Tire pressures range from 42-44 psi front 27-30 rear. Those are with street tires.

Good luck in dsp. Those race tires are but with the mods you have u would be better off with max performance street tires.

 

I noticed while driving on the autocross (Freeway actually). You have to slow down enough through the turn and accelerate through the turns. When you let off the gas, the car understeers but when you accelerate the wheels take you through the turn. So slow down enough before the turn and accelerate through the turn.

 

Pressures I ran started off at 45 front and rear, but the fronts were lowered between every run. My RSB is on the heaviest setting. The D2's have 6 turns of adjustment and I had both front and rear set 2 turns out from full stiff. Alignment hasn't been done yet because it needs to be corner-weighted too, but calculations showed my camber to be at about 2.5 deg. I have no idea what my toe is right now.

I know some of it is just not knowing how to handle my car yet, but something is up. My bf also drove my car because his 510 is in a few different pieces right now and he was having trouble too. But he's used to a light RWD drive car, not a fat *** FWD.

Unfortunately our summer series here is run at a police training road course that does not allow novices to run for safety reasons... so I won't be able to run again until september.

 

Mind telling us how you did that?

 

So... no one ever answered about disconnecting the front sway bar...

 

Seems like a good idea. Maybe on a VQ (alumin) max it might work. But at least on my VE30DE maxima (iron block/heavy), even the stock FSB, made this car lean WAY to much in the front. I even ADDED a high performance FSB. Made a big difference in preventing the front end from diving when into the corners. I'd shutter to think how a heavy FWD maxima would handle with no FSB at all.

 

Exactly. Disconnecting the bar will make the car lean a lot. It's done a lot on FWD cars to make them turn, but remember, you're autocrossing, not road racing. The MAJORITY of turns on a track are STEADY-STATE turns. Autocross is about rapid transitions (slaloms) with not as many steady state turns. You're gonna push no matter what you do. I'm assuming you're in a street tire class. Whwy did you lower tire pressures? After a point, they're just going to roll over, which still means push. Getting the back end a little stiffer would probably help as well

 

Just seems to me that making each front corner dive in more w/o the bar won't benefit the car enough to to jusify the better turn in rate. I'd much rather just stiffen the rear end as much as I could vs getting rid of the front bar.

 

Yeah, Jeff. We're basically saying the same thing. Besides, the turnarounds for most courses are fairly slow, so disconnecting the FSB probably won't make a difference there. He should concentrate on the alignment, not just camber, TOE is also important, as well as suspension and of course, driving.

 

Thanks everyone... and I'm a she, not a he.

 

also dont just go changing everything around at once, change one thing then test it to see if it made a difference and writing down what u change can help alot, tire pressures do make a big difference and are the easiest things to change i use 40 front and 30-35 rear on the stock wheels

 

Yeah I know... I have lots of time to think about it before I can run again in September. Stupid rules.

 

Which spring rates did you get with your D2's?

 

of course, understeer/oversteer can also be affected by playing with tire width/rim width.

For example, I run 225/45/17 up front on 17x8 wheels, and 225/45/17 on the back on 17x7.5 wheels....I wanted the more vertical sidewall up front for less sidewall roll into hard corners on the auto-x.....

Likewise, if you have all the same rim widths, you could consider going to a staggered tire setup (wider up front or in the back)...play with it a little to determine how you like them best....

my ideal setup would be a 17x8.5 rim up front with 245 rubber and 17x7.5 in the back with 225 rubber (reverse stagger)....

and yes, I know 245 will kill me in SCCA, but I'm racing local club this year because SCCA is just too much of a clusterfu-k around here...that and my LTB already screws me in SCCA regs...

 

9/7

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Wow that's pretty stiff. When I was looking atthe d2 i was thinking 10/8 so it be a little stiffer than my 500lbs/400lbs setup eibach Ground contol setup.

With that setup u would want your front struts set on a softer setting you said there are 6 settings. Probably the the 2nd or 3rd would be enough. For the rear the last 2.

In order to get more rotation out of the rear try lowering tire pressures. 30-35 is way too high at least for my cars setup id try 25 and work from there. Since you have coil overs try rasing the rear .5 - 1 inch.

How I got -1.1 deg camber in the rear not sure I believe that was the setting the last time i got an algniment. I'll let u know next week, since I 'll have to get an alignment next week after the new AGX get installed.

 

I get alot of oversteer if I pump UP my rear tire pressures.

Can anyone tell me more about toe-in and if it would help with high-speed turns? Any effect on daily driving tire wear?

I think ive got a neutral toe setting, but since I'm considering going back to the alignment shop ... might want to change that. Im leaning (no pun intended) towards dropping down from -2.2 camber to something that I can live with on the street/track re: tire life. (thinking 1.6) It was cool when I had to fight rollover on stock suspension- but now I even get ridiculous wear on the inside of my track tires. (thinking from hard braking) ... it used to only be the outsides... And my street tires are ridiculously not worn on the outside by the time I have to replace em.

 

too much toe out will cause much more tire wear on the insides than any amount of camber, i would suggest putting some slight toe in in your case if you have excessive inside wear, it will increase understeer but it seems like you dont have too much problems with that as you say you can get alot of oversteer, also neutral toe is best for road course , it can get really twitchy with a lot of toe out on high speed straightaways, toe out is mainly to help turn in response on autocross where you need to change directions rapidly

also slight toe in should help with braking and stability

oh yeah, the idea behind pumping up rear tire pressures to get more oversteer is that you overinflate them to lose some contact patch

the idea behind lowering rear tire pressures is that you underinflate them so the sidewalls roll over more and lose traction

either way works in theory, i cant get any oversteer with increased rear presssures tho so i dropped them down and it handles better

 

Sorry for the late response; just got back from Cancun.

I've been fighting understeer myself for a couple years. I no longer run a FSB. Yes removing the FSB can help but you'll need to compensate with stiffer front springs, FSTB, LTB, etc. to offset the roll and keep the steering crisp. For daily drivers with 500lbs or less front springs you might want to custom build a smaller FSB for $200ish. Any lesser springs won't support that weight.

Playing with pressures and the RSB should happen after the alignment. Toe out vs neutral or in makes a huge different in turn in. I'm running 1/4" total out which is creating a bit too much wear for my street driving. I'll go back to 1/8" total out ASAP.

Oh, and tire stagger helps too. Consider not only 245/225 or 225/205 but different compounds as well. I'm finding 140-200 treadwear in back too sticky and moving to a 300ish less grippy rubbber. Tire pressures from 35-60 in back never released with sticky rubber.

 

Spanaird, unless you have camber bolts or pillow ***** your stuck with that camber.

I've never done it on the auto-x but i can coax oversteer fairly consistantly. My front brakes are pretty poor despite the new R4-s. They just fade really quickly. Anyway, when the brakes are fresh I can induce oversteer by coming in hard turning and getting on the brake real hard. It wouldn't be bad at auto-x speeds but it gets to my threshold of fear at 70+.

 

Bejay, can I ask why you removed the front bar only to run really stiff front springs?

 

It's somewhat unrelated. My original springs of 450lbs were too soft for very aggressive cornering and braking. I tried shorter springs of the same rate with similar results. After talking with Progress, Eibach, Catts, Hypercoil, and TNR, I decided on 650-675. 700's were quickly available locally.

Removing the FSB was done long before the springs as an alternative to building a tougher RSB or boxing the beam. Oh, and having an LSD up front entered in the thinking too.