Ran my first event in the 2002 996 C2 this weekend. Last year I was running a stock 350Z on Falken RT-615s and often had best time for street tires... after this event I was 5 seconds off the pace on an 85-second run... sadness. I'm on C2 rims (225/40/18 & 285/30/18) running Continental ContiSportContact2s with a stock alignment. Everyone is telling me the Conti's are garbage for AutoX, but that doesn't explain the 5 second gap. Part of it is ME of course, as I have to get used to the car, but maybe you guys can help me dial in the tire pressures and alignment to eliminate two variables.

1st & second runs were on stock tire pressures (35lbs F & 45lbs R). UNDERSTEERING HUGE.

3rd run (40lbs F & 45lbs R). Front hooked up much better but the back-end was all over the place.

4th run (40lbs F & 43lbs R). Same problem as 3rd run, but I may have lifted on the thottle in the middle of the corner when I spun. (Habit from the 350Z).

Any suggestions as to who else I could talk to? PCA? SCCA?

Thanks

Joe

 

Hello.
I am guessing this is your first time autocrossing a 911 vs. brand 'X'.
This car needs to be driven alot different than what you had run before.
Try braking really late & hard before you need to turn, this will help abunch (need to load the front wheels with weight), running with full fuel tank can help, too.
Basically, just seat time is most important.
Tires are the next best thing to do, too.
However if wear isn't a concern, let some air out next time, especially up front...it will help you hook up.

 

Except when I went from 35lbs up front to 40lbs it improved the front traction.

I think you're right though... I need seat time more than anything else.

 

I think that you are running way to high pressures especially in the rear. I know very well Porsche recommendations that spec 44PSI on the rear, but this is more for liability reasons than anything else. Running 44PSI is a recipe for disaster on the track...
I have run for a few years street tires on tracks and now I still have streets on my cabrio which I autocross.
I run 18" Dunlops and on cold days I run 36PSI all around. On Hot days I would run a 34 front and 35 rear. I would recommend you start like that and see what happens. An aggressive alignment would help, if you can dial a -1 camber front maybe a -0.7 rear, that would be a decent compromise for street and track and the turn in will improve.
However do start with low pressures and take it from there.

 

My recommendation would be to dedicate your entire focus at this point in your autox career to driving. Find the fast guys in your club, go for rides with them, have them ride with you, even have them drive your car with you in it.

You'll have plenty of time to worry about set-up, tires, etc. after you've learned all of the autox basics (looking ahead...FAR ahead, staying close to cones, managing the contact patch of your tires, etc). It's so tempting to do a first or second autox, see times way off the pace of many others that have been doing this for a while, and start tinkering with R-Comps or different suspensions, or even alignments. All those things are important, but only once you have the tools to know what you really need, and how to use those tools. Until that point, they become more of a distraction to learning how to autox, and in fact, often slow the learning process.

 

Unless you have been autoxing for about 5 years, you are not experienced enough to be worrying about tire pressures. This is a common newbie mistake. I would suggest you set your tires to about 35-36psi and forget about it.

Rich
PCA-CWR AutoX chair

 

Listen to those guys above about tire pressures and keep it under 40psi. When I let the pressure get above 40psi it's like I'm driving in the rain.

The other thing to remember about a 911 and cornering is "slow in, fast out". Not "fast in, slow out" like I started doing at the beginning of the year. Use those great brakes of yours and get down to the right speed for the corners. Trailbraking helps a lot too.

One example, for a 180* sweeper what works well for me is to fly up to the sweeper and brake hard in a straight line to get almost all the speed down - continue braking while turning but you aren't braking as hard here. The weight transfer to the front is helping give the front tires extra "bite" to help turn in. (Too fast here and you'll understeer and plow off the line.) Smoothly transition from the brakes to the gas and squeeze the throttle as you fly past the apex and are exiting the corner.

When you nail this it's a great feeling. You'll know it when it happens.

Cheers,

 

Thanks for the input guys.

This is the begining of my third year of AutoX. I've got a fair understanding with my 350Z (usually running for fastest overall time on street-tires). My pressures on Azenis were 39 F and 42 R. With the motor moved to the back, it's a different animal, and wasn't sure where to start with pressures.

I'll go ahead with the recommended pressures and alignment and go from there. Thanks again.

 

I thought the addage was "Slow in, Fast out, not Fast in, Out backwards."


On topic: I think part of it might also be that 996's in base trim aren't great autocross cars. I'm by no means a great driver (not even a good one), been autocrossing for only 3 years and did pretty darn good at the last PCA autocross in my STi (Second autocross in this car, stock except for mods in sig, spare tire in trunk, 3/4 tank of gas). The cars ahead of me were all on R compound tires except for the GT3, and the 914s were all stripped out track cars. I also squeezed out a 46.0xx but clipped a cone. The 996 Driven by Matt Deter was on Pilot Sport Cups (He also has about 3 yrs auto-x experiance).
See Times -> http://svr-autocross.deter.com/SVR%2...02007May12.pdf

Keep practicing and follow the advice above.

Cheers,
Dan

 

FWIW - The tires you have on the car aren't complete trash. . . in fact they're better than a lot of all season tires and kick butt in the rain. I ran on those at Solo Nationals in 2005 in STXL and placed 2nd. They couldn't have sucked too bad. . .

 

The Nationals?
That's great!

 

I'm going to respectfully disagree with most of the advice given here. I followed it all, and did horribly. I finally talked to a BMW club member who used to race P cars competitively. He told me to raise the fronts to 42psi, and lower the rears to 40-42psi. My times went down, A LOT. On our cars, sidewall stiffness plays a huge role IN AUTOCROSS (not as much on the track). The stiffer sidewall up front helps our cars rotate the back end around tighter turns.

I've been autocrossing for about 5 years, and road racing for longer. This went against all conventional knowledge. All I know is that it worked

 

On Saturday I did some testing on the skidpad and a short AutoX course. The pressures that seem to be working for me at 24 degrees celcius are 40.5 psi up front, and 44.5 psi in the back. I'll continue to tweak, but thought I'd share my findings. Haven't gotten around to an alignment yet.

I tried dropping pressures to as low as 37/41 psi and ended up being a half second slower on the 10 second skidpad... as I increased pressure I decreased time. (Tires were already warmed up before I started testing) Unfortunately I ran out of time to test the really low suggestions (34-36psi)... next time.

edit: I just realized I've already tried 35psi up front and did horribly. Next event, I'll try running pressures a little higher yet.

 

Sorry for the OT, but, Tara (Imprezivblue), when did you start hanging out on P-car forums? And, more importantly, when are you coming up to play with your So. WV Region friends again?

 

No problem... but that's what private messaging is for