Hello All,

I just recently bought my first Crossfire, a '05 alabaster white with an autostick and 5k miles. I love the car and am having a blast driving it on the street. The Crossfire replaces a 1995 LT-1 Corvette that I used mainly for autocross. While the Crossfire will be used mainly on the street, I can't totally give up Solo 2.

I've been autocrossing for 10 years or so and have had some success in a number of different classes although, mainly street tire classes (regional classes). I plan on running the Crossfire in D/Stock on street tires. In my region, it is a very underscribed class but I should have a few people to run against.

I'm running fairly new Hankook Ventus S1 Evos in the factory size,and everything is stock, including the alignment.

My question is, Would anyone like to hazard a guess on starting tire pressures?

Any other suggestions on set-up would be very welcome.

Bryan

 

Open the driver's door... right hand door sill where the striker is. Start from there -2 lbs.

 

Congrats and welcome. There are three or four successful autocrossers who are active on this forum. If you use the search feature, you will find them quickly and easily, and I'll bet they will have some great advice. Good look.

 

MMZ is pretty close to correct... Autocrossing doesn't give your tires much chance to heat-up and most events don't let you do burnouts to heat them before your event starts. A good rule of thumb is that your tire pressure will increase 1 lb for every 10 degrees increase in operating temperature. So many AutoX'rs will start with a couple of lbs under suggested pressure then run one event and immediately check the pressure to see how much it increased during the run. Then they will adjust the pressure to adjust the handling characteristics of the car... eg. oversteer / understeer... There are some good articles on pressure adjustment in the tech articles section of the TireRack website...

 

Thank you for the info thus far. As I said, I've been autocrossing for a number of years and am very familiar with adjusting handling by adding or removing pressure from either the front or rears.

In my last autocross car, a C4 Corvette, I could get the car to rotate the rear with change of 1 lb. in the rears. Of course this would change according to all the typical conditions such temperature, asphalt or concrete, and a myriad other conditions.

I'll start with 40 psi and check rollover. Eventually I'll set up a test session for the Crossfire so I can use my pyrometer to try to balance the temps across the tread width, but for the remainder of this season, I'll just run it with the current alignment settings.

Thanks for the welcomes,
Bryan

 

I ran two events with my car on the stock Continental Contisport2 tires before switching to full race tires. My pressures were in the mid 40 psi range in front and about the same in back. That is with -1.5 degrees of camber in front and stock springs but the SRT/AMG front sway bar mounted in delrin bushings. The car will eat the outside shoulder of the tire if you leave it under inflated at all. My car and one other ate through a pair of very pricey Hoosiers very quickly earlier this season even with high pressures. Thankfully Hoosier replaced the tires for free because they have been having issues with wear in that particular size. The Kuhmo fronts I have now are wearing better. Hope that helps you out some.

PS: The largest difference in handling after I added the Koni shocks was taking out almost all of the rear toe in. It makes the car rotate so much better now.

 

But aren't your wheel and tire sizes completely different than the OEM ?

 

SoloIIracer, Thank you, that's the kind of info I'm looking for. I'm thinking that when I get it aligned I'll start with 0 toe front and rear and max the camber in front. I'll start with mid 40's for pressure and see what that gets me.

One question, I know that rear chamber is not readily attainable but how much can you get out of the fronts?

I'll have to do so more research on the front bar, I know traditionally rear wheel drive cars in stock class "usually" respond very well to a bigger bar.

 

I wouldn't start any lower than 40 in the front. I think the few short runs I took on my stock all-season Conti's I ran 40F/40R and that worked ok (well, as ok as an all-season tire can work). On race rubber (which is non-stock size tires on stock size wheels) I've had to run in the neighborhood of 47F/45R. This all with a setup slightly different, but very similar to soloIIracer.

The car is going to be tough on front tires...keep a close eye on how far you're rolling them over.

And don't forget to turn the ESP/TC off...or as far off as you can get it anyway.

 

There is a camber kit available from Chrysler...essentially a notched bolt that'll give you a little bit more front camber.

I've got the H&R front bar (which I think is 30mm) on my car and I feel like it was a big help...along with some front toe out. I've got zero toe rear.

 

Bryan, Thanks for the info, especially on the front bar. That may very well be my first "autocross related" purchase.

I didn't realize there were crash bolts available for the Crossfire. When I ran a VW Golf in E/Prepared I ran similar bolts and gained almost a degree of neg. camber.

Our next solo is on the 15th, I'll post the results and my reactions.

Again, thanks everyone for the good info.

Bryan
#22 D/Stock

 

No problem...best thing about the bar is that it's cake to install...nothing but a plastic tray in your way.

You're not going to get a degree from the bolts...expect a few tenths...then maybe you'll get a half degree and be pleasantly surprised. Same bolts can be used for the caster adjustment as well (which I haven't done).