AutoX questions

[firestarter2]

What tire pressures are you guys running on the stock wheels? Is an alignment with it if you dont have camber plates?

Any other suggestions.

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[GT_Dave]

If you are just starting out in Autocross, go with the factory suspension settings. For tire pressure, it was recommended to me by some expert AutoX drivers to run my tire pressure at 32 PSI in the fronts 34 PSI (cold) in the rears to start in a car this heavy. On a really hot day you may want to go up to 36PSI in the rears. Those settings have been working good for the MPSS tires. Variance from these adjustments will depend on the surface conditions and track layout.

 

[firestarter2]

Interesting I've run much higher psi on other cars with albeit much smaller wheels

 

[J_Maher_AMG]

Well Ford Performance recommends 28psi for track use on the R, not sure if its the same for the 350. I would think mid 30 psi pressures would be too high, especially once the tires heat up?

 

[BlkGT3]

MPSS with its soft sidewall needs to be in the 38psi range for Autox. If you were running a stiff sidewall tire like an AD08R or a RE-71R I would say 32 to 34 psi.

Peter

 

[Sid]

If you plan to autocross regularly a good investment is a tire pyrometer. http://soloracer.com/pyro3.html consistent temp across the tire generally means you are running the correct air pressure. Take a run and when you get back to the pits immediately jump out and take your tires temps and adjust accordingly. I'm sure someone has one you could borrow at the event. I personally like my cars to be a little looser in the rear so I would fiddle with the PSI until I got it to do what I wanted. Heat is a factor in keeping tire temps even. Even having one side of your car sitting in the sun can bump up the psi on that side. Check just before and after your run and take mental notes on what your car is doing and soon you'll get a pretty good idea what your tires and car needs.

 

[TDC]

Using a pyrometer on factory alignment I've found 36 front 34 rear worked well. The pressures will climb about 3 or 4 psi after several runs.

I've tried 32 front 30 rear and it felt like the sidewalls were rolling over and the car lost the sharp steering feel it normally has.

Fronts and rears definitely need more camber as the inside wheels always ran 3-5 degrees cooler than middle and a few more degrees cooler than outside edge.

 

[firestarter2]

OK I will try that I think we have infrared thermostats at work I'd like a little more rotation

 

[Hughespj47]

The alignment card that comes with the owners manual recommends 28 psi. This is for the TRACK. I called FP and they said the lower than normal pressure is needed because the hard running on the track causes them to heat up more than on the street. The exact opposite is true of autocross. Have fun!

 

[nastang87xx]

I run 29 front and 28 rear on R-S3's. I ran 32 and 30 on my Super Sports. I am regularly behind C5 Z06's, which is THE car to have in A Street, by a second or so with the R-S3's. 2 - 3 seconds if they're on Rival S's or RE71R's.

Look at your tires. If they're rolling over too much by the indicator line, pump them up. If they're not rolling over at all and you feel like you're on ice skates, bring em down. Like everything else with cars, it's about FEEL.

 

[firestarter2]

I embarrassed my self as usuall. I got to 33.5 front 30 rear with out any noticeable roll over. Ill mark the tires next time

 

[Tank]

Thought reading was fundamental....This is from the Ford Performance brochure "Track Tips" in your Shelby Owners Manual Supplement.

 

[firestarter2]

Thought reading was fundamental....This is from the Ford Performance brochure "Track Tips" in your Shelby Owners Manual Supplement.

Autox settings are not track settings. Typically you run lower pressures on track then autox.

 

[Tank]

Autox settings are not track settings. Typically you run lower pressures on track then autox.

Yeah, what I posted were for "road course track days"...

 

[firestarter2]

Yeah, what I posted were for "road course track days"...

You trolling me? Did you see the title of the thread?

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