trophy

Hey Guys...

I have been a track junkie for almost 30 years and am pretty comfortable in knowing what my car needs to get the most out of it at any given track. Autocross is another animal entirely, did my first autocross on the weekend, left the car setup as it cam from the track (very stiff - shocks, sways etc) and it looked like i was competing in Formula Drift rather than autocross, the car was (as expected) very loose, front grip was good to ok, but any trail braking would get the rear loose and any application of power (however small), would have the car sliding alot...

So, how should the car be setup? Looking for tips on swaybars and shocks... alignment could use a tweek or 2 but I think is pretty good, the car just feels very stiff.

Any ideas direction is appreciated (I don't compete in anyway, car is stripped for track and has way to many mods to be competitive in the class it falls under) If you prefer to connect via PM to protect your 'investment' I understand

abqautoxer

Often you can just greatly soften or disconnect the rear bar to get your track setup in the ball park. Since we don't know the specifics, it's hard to identify much. Generally speaking on the 993 C4S I borrowed for events, we set it up so it had a minimum of push on exit with rear toe and added enough front bar to make sure the rotation on entry was controllable which had the added benefit in slaloms. This was stock class so springs weren't a tuning option. If everything works well, you can rotate the car on entry with the brakes predictably and throttle early to slow rotation and exit.

trophy

Thanks for the ideas...

The car rotate's well on entry with trail braking, it's on exit I am having trouble putting the power down. Which is really a factor of how stiff the swaybars are and the springs I am using.

Swaybars are TRG ones, so they are very big and the rear is set at full stiff and the front is set 2nd from full stiff.

Springs are 700lb rear and 500lb fronts, these are up from the stock KW Clubsport springs that are 625 rear and 340 front.

Shocks have about 18 setting (compression), fronts are 6 from full stiff and rears are 4 from full stiff

Alignment wise:
Front:
Camber -3.3
Toe: -3.76 minutes (0.5mm toe OUT 18" Wheels)

Rear:
Camber -3.1
Toe: 13.16 minutes (1.75mm toe IN)

abqautoxer

If the valving in those is similar to the V3 for the 993, You have way too much compression all around but especially in the rear.

PedalFaster

To build on Tom's point, try taking all of the rebound and compression out of your rear shocks then doing a run or two. The car may feel terrible due to a lack of body control in the back, but that's fine -- the purpose of the exercise is to identify whether the issues are caused, and thus fixable, by shock adjustments. You can always turn the damping back up again if it's too soft.

If that's still too loose, the next easy and free test is to disconnect your rear sway bar.

Have you checked your alignment recently? Alignments can drift, especially from hard track use if you're riding curbs.

Last but not least, look at the nut behind the wheel. Consider asking one of the local guys who are known fast in different cars (like Cam in the blue Corvette or Ryan in whatever car he's driving that day) to take your car for a run. It could be that you're just manhandling the car in a way it won't tolerate.

Good luck!

trophy

Great points thanks guys...

I knew the car was going to be too stiff for autocross, just didn't get time to make any adjustments prior to getting out on Sunday.

I do think its shocks and sways' the alignment is perfect, I do it at home myself and was checked last week.

The nut behind the wheel could be an issue, no doubt. I have been a track guy for many years, raced for many of those. Can get 10/10ths out of the car on a track no problem, need to readjust my driving style to an autocross course. It was a challenge on Sunday due to how loose the car was, even with the lightest throttle input the back end would break loose.

Hopefully get out for the last YYC day and get some adjustments made prior and see what happens...

Thanks again.

mopar bob

You need some neg. toe in the rear. I ran 0 toe last year and the car didn't come out of the turns well plus I spun more than once. OK I spun a lot. Soften the rear bar, I run a stock rear swaybar and a GT3 front on the middle setting. You also may need to run lower air pressure in your tires.

abqautoxer

In SCCA Street classes, most of the Porsche chassis are going to like zero and some like a little toe out in the rear. You just set your front bar and adjustable shocks to fix transitions. Otherwise you get way too much exit understeer. The problem is always sourcing good adjustable Street class legal shocks. Without those elements, yes it will suck.

certz

If you are planning to still track the car and like your alignment for that use, then I would not touch it. Otherwise, if you intend to do more AX then you are running way too much camber. AX is just like the track in that you want to maximize your contact patch, but with the camber you are running you will only have instantaneous g forces enough to make use of those settings. I run the C2S at AX at it is setup with a very slightly aggressive stance - IIRC -1.5 front, -1.25 rear (pretty upright compared to the track car which has settings similar to yours).

I do not agree with running lower tire pressures. Your target pressure is the same as what you run on the track. The difference is you will start the pressure much higher than you do at the track since you will not put the same amount of heat in the tire at AX.

I do agree with everyone else as far as softening your suspension settings. You probably have enough spring on the car that you can run minimal compression, but I would not be too fast to drop rebound to nothing - you still want to limit squat. I am not that familiar with KW's, are the V3's 3-way? If so, then you can drop high-speed compression to minimal and just use low-speed compression for body roll.

abqautoxer

Strangely, I couldn't disagree more about the camber. The bars could be softer but the camber is ball park right, usually less in the rear works a touch better but -3 isn't impossible to fathom working at all. I'm sure someone will disagree and all I can offer is my experience tells me what I know works. Compared to track use you run a bit softer and less twitchy but the chassis will roll plenty for sustained periods of time (look at data acq) and there are a lot less straights over those 60 seconds.

jpgunn

Soften the rear bar

sl951

+2 soften the rear bar

trophy

Thanks to everyone for weighing in on my request, much appreciated...

I will still be running between track and autocross next year, I align at home (rack, strings, yada yada) so happy to readjust the car for any given event, which I usually do anyway.

Softening is the consensus, I agree with the compression/rebound argument, I find with too little rebound the car ends up porpoising too much, some minor adjustment will be in order, not full soft on rebound though.

The KW's are 2 way only, compression and rebound.

I agree with the swaybar settings, thank you...

My car is not legal for any street/stock classes so everything is as adjustable as it needs to be.

Thanks for the opposing opinion, this all gives me lots to work with...

Thanks

edfishjr

Friend auto-x's a 993 locally in BSP, basically in RS trim. Got it handling really well with -3 in front, -2.5 rear. About 450 lb/ in front, 700 rear, MCS shocks. It hooked up once he got the rear rebound low enough. Slight toe out in front, slight toe in rear. Lots of time spent working on the kinematic toe adjustment.

trophy

This is great, thanks!