How much air in tires for Autocross?

[BaylorCamaro]

About to do my first autocross next weekend, and was wondering what the ideal tire pressure (operating temp) would be for autocross. I know for the drag strip I over inflate my front and deflate my rears.

My tires are 255x20 front and 275x20 (Pilot Super Sport) rear.

[rocketman 12]

[K32 Camaro]

[Dalefj]

what pressures did you wind up using?

[was619]

The one time that I went to an autoX in the camaro I checked the tires between runs just to make sure they were below 40psi. after my fastest run they were around 38 or so.

What did you end up doing...?

[ICTsccaCamaro]

For us im running around 34psi front and rear anything higher and the car is very loose our next event is the 5th and i may play with running lower, but we also have quite a bit of camber in the car front and rear witch will change how the tire rolls

[SS_Killer]

Originally Posted by BaylorCamaro

About to do my first autocross next weekend, and was wondering what the ideal tire pressure (operating temp) would be for autocross. I know for the drag strip I over inflate my front and deflate my rears.

My tires are 255x20 front and 275x20 (Pilot Super Sport) rear.

On the same weekend I had the pleasure of driving not one, but TWO Camaros. Mine (v6 setup for autocross) and my brother's SS, cammed (camed?) and setup mainly for drag racing. His dyno reported 527 hp! His car is actually a tweener. It has stiff sway bars and all kinds of solid bushings, but no camber. He also has the same tires as you, except the rears might have been 305s. My car wears Dunlop Dirreza Z1 tires in a 245 profile front and rear.

Long story short, I inflated his fronts to 40 and his rear to 35. His car was a handful for me, to say the least. My main observation between his and mine was that his car pushed in the turns while mine is neutral with the same inflation pressure. Next time (there may never be one), I would even out his inflation pressure front to back at about 36 and loosen his front sway bar to the middle hole. I expect that might neutralize his handling.

Bottom line? I drove his car twice and mine eight times that day. My fast time in my car was 2.1 seconds quicker. I am much more familiar with my own car, of course, and could probably have equalized my times, but I am not sure how his could be quicker. 2.1 seconds is almost forever on a 35 second autocross course. Hence my handle, I suppose.

Are you anywhere in the Midwest Region? I drive in Portage and South Bend, Indiana. Been thinking about the Chicago and Fort Wayne Regions too.

[BaylorCamaro]

Originally Posted by Dalefj

what pressures did you wind up using?

Originally Posted by was619

The one time that I went to an autoX in the camaro I checked the tires between runs just to make sure they were below 40psi. after my fastest run they were around 38 or so.

What did you end up doing...?

So I went to the autocross event had had 38 psi (on hot tires) in all four corners. Seemed to work ok. My best time on the course was 50.3 seconds the lap record was 44 seconds set by a 1LE, the average times were right around 50. Being my first time to autocross and having a V6 I think I did ok.

Most importantly I had a blast and now I'm hooked. Much more fun than the 1/4

Here's a video of three of my runs (worst to best)

[rocketman 12]

Originally Posted by SS_Killer

Are you anywhere in the Midwest Region? I drive in Portage and South Bend, Indiana. Been thinking about the Chicago and Fort Wayne Regions too.

I run at Fort Wayne, made it to two events last year, planning on a full or close to it season this year with a trip or two over to South Bend. The points winner for F Stock last year ran a 2010 SS, he moved up to ST this year not sure if its X or U...... I'm planning on staying in Stock for at least this year. It would be great to have you at any of FWR's events, we're the only two 5th gens there and we have our hands full with a herd of Mustangs and a lone SRT Challenger.

[SS_Killer]

Originally Posted by BaylorCamaro

So I went to the autocross event had had 38 psi (on hot tires) in all four corners. Seemed to work ok. My best time on the course was 50.3 seconds the lap record was 44 seconds set by a 1LE, the average times were right around 50. Being my first time to autocross and having a V6 I think I did ok.

Most importantly I had a blast and now I'm hooked. Much more fun than the 1/4

Here's a video of three of my runs (worst to best)

It has been said that 1/4-mile drag racing is for fast cars, while road racing is for fast drivers. Auto-x is more like road racing that 13-ish seconds standing in a straight line IMHO.

After looking at your vids, I see that for a novice you take a very good line. I envy your supercharger.

And, please answer, are those Ventus V12s (or something like that) for tires? If so, makes your performance even more impressive.

[SS_Killer]

Originally Posted by rocketman 12

I run at Fort Wayne, made it to two events last year, planning on a full or close to it season this year with a trip or two over to South Bend. The points winner for F Stock last year ran a 2010 SS, he moved up to ST this year not sure if its X or U...... I'm planning on staying in Stock for at least this year. It would be great to have you at any of FWR's events, we're the only two 5th gens there and we have our hands full with a herd of Mustangs and a lone SRT Challenger.

I think you are talking about BG winning the points last year. We met at Grissom last year. He's a super nice guy doing hero's work if you ask me, even if the v6 easily handled him and his co-driver. Fort Wayne is a little bit of a drive for me, and my schedule is full with Indiana Northwest and South Bend Regions this year. If I actually make all the events on both calendars, you will see me a couple times at the SB Tire Rack! Nothing like "racing" against another C5!

[nrr8865]

BaylorCamaro, I run BFG Comp 2. Ran them at 38 cold. They heat up to around 40. The edge of the front tire start to cup if I run anything below 38. These tire were a bad choice. Have some friends running Nittos. Will see how they hold up.

[BaylorCamaro]

Originally Posted by SS_Killer

It has been said that 1/4-mile drag racing is for fast cars, while road racing is for fast drivers. Auto-x is more like road racing that 13-ish seconds standing in a straight line IMHO.

After looking at your vids, I see that for a novice you take a very good line. I envy your supercharger.

And, please answer, are those Ventus V12s (or something like that) for tires? If so, makes your performance even more impressive.

Thanks. Yes they are Hankook Ventus V12's in the front. I got them a looooong time ago because of their cheap price, and at the time I was drag racing so front tires weren't really a concern for me at the moment. After the autocross event I realize I need slightly wider and better front tires.

[rocketman 12]

Originally Posted by SS_Killer

I think you are talking about BG winning the points last year. We met at Grissom last year. He's a super nice guy doing hero's work if you ask me, even if the v6 easily handled him and his co-driver. Fort Wayne is a little bit of a drive for me, and my schedule is full with Indiana Northwest and South Bend Regions this year. If I actually make all the events on both calendars, you will see me a couple times at the SB Tire Rack! Nothing like "racing" against another C5!

Yup, that's him. He was throwing down some impressive times with just a rear sway bar and high performance tires. Great guy too, like you said.