autocross questions
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From: Bryant Ar.
autocross questions
I have a '07 A6 and was wondering what tire pressures should I try using for an autocross. Times should be under 1 minute. Also with the A6, should I use the competitive driving mode, paddle shift, or just drive in 's'? Any input would be helpful.
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St. Jude Donor '08-'09
Most advice I've heard is 28# rear, 34-36# front, comp mode, paddle shift and keep it in one gear as much as you can.
Le Mans Master
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From: Chandler Arizona
I was also told to run high pressure in the fronts, but man, the car really pushed (understeered) badly. I run 30 all around and it works great. If I don't drop the pressure between the runs (builds up due to the heat), I will start pushing again by the last run.
Drifting
Joined: Nov 2005
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From: Turlock CA
Most autox courses will be run in 1st gear with some use of 2nd. 1st is good for 50+ mph. The A6 with 2.56 gears won't pull the slower corners as well in 2nd as the manual cars usually can but will run out to 85+. Use the paddles which will keep the car in the selected gear even to the point of bouncing off the rev-limiter -- which can be a better choice than shifting at times. If you're lucky, you'll get to use 3rd gear on courses in your region but that's pretty rare.
--Dan
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From: Chandler Arizona
I turn AH/TC off by holding the button for 10 seconds as listed in the manual. This allows the car to break loose and slide while maintaining ABS for braking. There's no better place to learn the limits of you and your car than an autox course where there is nothing (usually) to hit. Comp. mode will still intrude on your throttle and braking and if you are attempting to shift it will prevent you from doing so until the computer feels it's ok.
Most autox courses will be run in 1st gear with some use of 2nd. 1st is good for 50+ mph. The A6 with 2.56 gears won't pull the slower corners as well in 2nd as the manual cars usually can but will run out to 85+. Use the paddles which will keep the car in the selected gear even to the point of bouncing off the rev-limiter -- which can be a better choice than shifting at times. If you're lucky, you'll get to use 3rd gear on courses in your region but that's pretty rare.
--Dan
Most autox courses will be run in 1st gear with some use of 2nd. 1st is good for 50+ mph. The A6 with 2.56 gears won't pull the slower corners as well in 2nd as the manual cars usually can but will run out to 85+. Use the paddles which will keep the car in the selected gear even to the point of bouncing off the rev-limiter -- which can be a better choice than shifting at times. If you're lucky, you'll get to use 3rd gear on courses in your region but that's pretty rare.
--Dan
Le Mans Master
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From: Chandler Arizona
40 hot is what I ran with my Camaros, however, with the runflats I've found that lower pressures work better. I use the old chalk marks on the sidewalls and the tires are not rolling over at 30 psig. Those darn runflats have really stiff sidewalls.
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Le Mans Master
Joined: Feb 2006
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From: Chandler Arizona
Le Mans Master
Joined: Feb 2006
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From: Chandler Arizona
I've run the Vette 5 times and have yet to be beat by a Miata in the street tire class. Even the ones with the gumball tires are not beating me. However, the 2 Lotus Elieses in the street tire class are beating me every time. Those things are go karts!
Racer
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From: Port Orange Florida
Kill the Miata
I am running in the modified class and only get beat when I am on a very tight course, Miatas, S2000 types are tough. Look at the national standing and you will see that 75% of the top 10 non pro's are driving these types of cars. Good luck kicking the crap out of those miats
Safety Car
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From: Tampa FL
I haven't tried the chalk. You're right about the stiff sidewalls. I've tried different pressures down to 30lb and haven't noticed much difference in my times.
Instructor
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From: Coral Springs, Florida, USA Florida
So far, I've been down to around 24 rear & 27 front with no real difference. Because of the stiff sidewalls on the GY Suparcars, I have a concern about using pressures higher than 30 in the front, which could cause the car to push more than I'd like. These tires don't seem to respond to pressure changes at all.
With the lower pressures, I can just begin to see the scrubbing on the edges of the tire.
As it is, I've seen a bit of chassis understeer that I can usually overcome with the throttle.
When the runflats go, I'll give the PS2's a try. At that time, I'll also get a performance alignment with the goal of tuning out the push.
Le Mans Master
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From: Chandler Arizona
I usually start around 30 ish all the way around, with the rears a few pounds less than the front. I decrease the pressure a few psi front & rear as the day goes on to see if it has any effect.
So far, I've been down to around 24 rear & 27 front with no real difference. Because of the stiff sidewalls on the GY Suparcars, I have a concern about using pressures higher than 30 in the front, which could cause the car to push more than I'd like. These tires don't seem to respond to pressure changes at all.
With the lower pressures, I can just begin to see the scrubbing on the edges of the tire.
As it is, I've seen a bit of chassis understeer that I can usually overcome with the throttle.
When the runflats go, I'll give the PS2's a try. At that time, I'll also get a performance alignment with the goal of tuning out the push.
So far, I've been down to around 24 rear & 27 front with no real difference. Because of the stiff sidewalls on the GY Suparcars, I have a concern about using pressures higher than 30 in the front, which could cause the car to push more than I'd like. These tires don't seem to respond to pressure changes at all.
With the lower pressures, I can just begin to see the scrubbing on the edges of the tire.
As it is, I've seen a bit of chassis understeer that I can usually overcome with the throttle.
When the runflats go, I'll give the PS2's a try. At that time, I'll also get a performance alignment with the goal of tuning out the push.
I did my first autocross with 40 psi in the fronts and the car would NOT turn in. I lowered it to 32 for the second event and the car was much easier to drive. I've found that anything between 30 and 34 seems to work fine for me.
Safety Car
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No you don't! Stock runflats anything over 34psi is too much and you will lose grip, try to keep them around 32psi. Turn all the nannies off.
Safety Car
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From: Tampa FL
Maybe that's why I spin out so easily! Anyway, the guys who run the Corvette Racing Club NCCC events I attend insist that 40lb is the way to go. I'll try your advice using lower pressures next time I go. In the past I haven't noticed much difference.
Instructor
Joined: Oct 2000
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From: Coral Springs, Florida, USA Florida
I heard the same thing from others giving advice to guys new to autocross. I suspect that these guys were talking about non-runflats.
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From: Bryant Ar.
Thanks for all the replys. I'm not new to autocrossing. Just new to autocrossing a corvette. I've autocrossed Porsche 914 fours and sixes for many years. My real love is driving on road courses. I'm a Porsche club driver's ed instructor. The only corvette I've driven at a autocross is a friend's at an autocross. It was really different than my 914. He drove my 914 and was really impressed. Thanks again for all the info.