I was wondering what types of tyre pressure people are running on their cars for an autocross. This is my first season running a SVT Contour, in the past i have run an Escort, Focus, and Mustang.
On my Escort i had AVS ES100's and i would go to the track with about 50 psi front and 40 psi rear, cold. After my first run i would adj. depending on how much tyre roll and how much the car is pushing.
The Focus and Mustang ran on slicks, setting up slicks is different than street tyres.
On my Contour i have Eagle F1's GS-D3, on the street so far i love them, looking forward to seeing that they can do on the track.
It just depends on the tires and your driving style. I haven't ran my svt yet so I don't really know what pressures I'll run. With my soft sidewall fuzions, it'll be pretty high, maybe a bit higher or the same as front in the rear to have it rotate good.
What Kremit said... it depends on the type of tires and stuff.
Also... on my SVT with Falken Azenis RT-215's, I run 52 front and 32 rear. Any less on the fronts and I start scrubbing the corner/sidewall. With 32 in the rear, the car is pretty neutral and I can get throtle induced oversteer to rotate around the tight turns. Any less in the rear... the rear slides too much; any more and I can't get the rear to kick out even if I try.
I need some Reccomendations, im running BFG KDW's 215/45/R16
Going to a track day this weekend and i was thinking maybe 27psi heated up? Help me out tho.
In my Escort i would run about 50 to 55 hot for a short autocross, about 45 to 50 for long ones, for open track events i would run about 45 hot front and 35 hot rear. Each car/tyre/driver is going to be different.
So it sounds like the contour might tend to push a lot in the corners, just like my escort did, thats why i ran so much pressure in the escort.
i run like 35ish in hte front and 37 ish in the rear on open tracks
With stock suspension and relatively soft sidewall tires like the Goodyears, you'll want to keep them pretty high. With more camber, rear roll stiffness, and total roll stiffness you can soften them up a bit, but it's hard to keep the tires from rolling over on a stock car. You proabably will find there's not much difference between 40 and 5 psi in terms of speed, but I'd guess wear will be best more towards 50 (cold) psi. I have run 48 psi with good luck, on stock suspension. Around 30 seems to be good in the rear, depending on the tire. I needed 34-36 to keep the Fusions from going too mushy in the back, but the MXs feel great at 30 psi.
Originally posted by Escortrs88:
So it sounds like the contour might tend to push a lot in the corners, just like my escort did, thats why i ran so much pressure in the escort.
My escort doesn't push. 
Originally posted by Auto-X Fil:
With stock suspension and relatively soft sidewall tires like the Goodyears, you'll want to keep them pretty high. With more camber, rear roll stiffness, and total roll stiffness you can soften them up a bit, but it's hard to keep the tires from rolling over on a stock car. You proabably will find there's not much difference between 40 and 5 psi in terms of speed, but I'd guess wear will be best more towards 50 (cold) psi. I have run 48 psi with good luck, on stock suspension. Around 30 seems to be good in the rear, depending on the tire. I needed 34-36 to keep the Fusions from going too mushy in the back, but the MXs feel great at 30 psi.
48psi seems nuts when its recommended at 30ish.. weird
Are you talking about stock door sticker? As in everyday grandma driving recommendation?
Originally posted by Kremithefrog:
Are you talking about stock door sticker? As in everyday grandma driving recommendation?
yea.
Sorry, this is my first track meet. my bad for being N00b
On the topic of door stickers, if you arent running stock size tires they no longer apply. My 18s are 40-42psi every day.
And yes, most people air up on track days to avoid the rolling over the sidewall. Here is the trick. If you dont have access to air while at the track, put a bit more air in your tires than you think you might need. Now, rub some chalk on the outer 1" or so of tread, and a bit down the sidewall (on the outside edge). Now go out on your first run.
If the tire is overinflated, there will be some chalk left on the edge of the tread. If underinflated, some of the chalk will be missing from the sidewall. Good inflation will remove the chalk from the tread, but it should still be on the sidewall. Simple enough?
The tyre chalk is a good thing to do, that will tell you a lot about what your tyres are doing. I almost always do that.
The air tank we have is small so i try to have enough pressure in the tyres and only use the tank to tweek the pressure, or if you are at an open track event and you have let a lot of air out when they were really hot, when they cool down you might not have enough to go home, the other reason for the air tank.
The next autocross is a two day event, the first day is test and tune, the second day is the race. That should give me a good day to set the car up for the race.
For day to day street use, i run 35 psi all around.
Originally posted by Escortrs88:
The next autocross is a two day event, the first day is test and tune, the second day is the race. That should give me a good day to set the car up for the race.
Where is that at?
The autocross is at Grand Valley State Unversity July 1 and 2. It is being put on by the Furrin Group, not SCCA. West Michigan SCCA, doesn't do much in autocrossing anymore and that is too bad, they are only holding two this year, one at in K-zoo at Wing and one at Gratten Raceway.
A few of us are talking about going to G-man in july some time.
We go to Gingerman about every 3 to 4 weeks, so next time should be about 2 or 3 weeks away. I will post on here and in the W. Michigan section next time we go. And if you go, make sure you let me know, if i don't run, i will for sure be there.
Are you going to the SVTOA event there, or anyone else for that matter?
I would like to, in the process of moving and changing shops soo money and time will tell
I've always considered the psi on the door stickers to be crap. Even with factory sized tires and stock suspension. It's an averaged (one size fits all) specification that leans more towards squishy than stiff. "One size" rarely fits "all".
On stock suspension with almost stock sized tires, I prefer 38-front, 34-rear.
Originally posted by morbid:
I've always considered the psi on the door stickers to be crap. Even with factory sized tires and stock suspension. It's an averaged (one size fits all) specification that leans more towards squishy than stiff. "One size" rarely fits "all".
On stock suspension with almost stock sized tires, I prefer 38-front, 34-rear.
id think youd want more pressure in the back.
Why in the world would you want more tire pressure on the tires with less weight on them? The lightly loaded rear end should usually be significantly less than the heavy front if you're going for maximum stick.
For street use i run 35 psi all around. I have stock suspension.
For track use i am going to crank the fronts way up and leave the rears about where they are at.
ran 36 up front 42 out back, rolled a bit on the sidewall on the rears and a bit on the fronts, coulda pumped the backs up to 45 and the fronts to 39-40ish
That sounds like you were running rear tires with a very soft sidewall.
That's odd that you would roll them over. I suspect you were just getting positive camber due to body roll, if you're stock. I don't roll at all at around 30-34 psi. Having the rears softer lets me run all sorts of rear stiffness and keep the rear end from being tail-happy. I'd much rather have more grip and less rotation than the other way around. Rotation feels good, but grip is faster.
Originally posted by Auto-X Fil:
That's odd that you would roll them over. I suspect you were just getting positive camber due to body roll, if you're stock. I don't roll at all at around 30-34 psi. Having the rears softer lets me run all sorts of rear stiffness and keep the rear end from being tail-happy. I'd much rather have more grip and less rotation than the other way around. Rotation feels good, but grip is faster.
Im stock suspension less SBC
SBC?
Even stock, the Contour needs lower pressures in the rear. What tires were you on?
Originally posted by Auto-X Fil:
SBC?
Even stock, the Contour needs lower pressures in the rear. What tires were you on?
BFG KDW 215/50/R16
After reading this post I put my fronts up to 38 psi for street driving and noticed a huge improvement. I was running 32 front and 28 rear and now 38 front and 32 rear. Awesome improvement in handling and much better grip from stand still. I wasn't sure whether it was advisable to run with higher pressure before I read this otherwise I would have done this sooner.
Tires Dunlop direzza 215/50/16 on stock svt rims and stock suspension.
Originally posted by SD_zac:
After reading this post I put my fronts up to 38 psi for street driving and noticed a huge improvement. I was running 32 front and 28 rear and now 38 front and 32 rear. Awesome improvement in handling and much better grip from stand still. I wasn't sure whether it was advisable to run with higher pressure before I read this otherwise I would have done this sooner.
Tires Dunlop direzza 215/50/16 on stock svt rims and stock suspension.
Put more in the rears, like 38ish and you'll find a world of better handling
A little more in the rear would probably be good, but most likely not 38 especially for daily driving. With most tires, you'll find keeping the rear a bit lower than the front is best on the street.
Tourige, I don't know why you're obcessed with higher rear pressures. I think if you're really seeing any improvements running that way you have an alignment problem. Depending on tires, 36-48 front and 30-40 rear is going to keep your contact patches correct, which is all we're trying to do here.
When I first got the car I was running 32 all round and noticed a huge improvement when I dropped the rears to 28. No looking back now.
Originally posted by Auto-X Fil:
Tourige, I don't know why you're obcessed with higher rear pressures. I think if you're really seeing any improvements running that way you have an alignment problem. Depending on tires, 36-48 front and 30-40 rear is going to keep your contact patches correct, which is all we're trying to do here.
I may have to fiddle with this a bit.
My car is lowered about an inch or so, so I have a bit more rear camber than stock. My stock 15" wheels with 205/60's are fine, but last year when I was running around with my Azenis on the back, on 16x7.5" rims, I did not get full tread contact with the ground--at least not in a straight line. The outer inch or so of tread was up in the air. It worked OK for autocross, but did make me a little nervous about tire wear on the street.
The camber in front is not so severe. Still, I ran 31 psi (as on the placard) on the street. I can't remember what I used for autocross--but it was a wet day so I left things pretty soft.
Ok, i went Autocrossing, Saturday was test and tune, good thing, very hard course, a lot of DNF's. I started out with 40 psi front and 35 psi rear cold. After a few runs they got up to 44 front and the rears stayed at 35. My tyre marker was gone, way to much roll over. The rear was loose, using left foot brakeing i was able to get the back of the car to rotate around the cones. The next day i stoped at the gas station by the track and pumped up the pressure to 48 in the front, they had some heat in them from the drive to the track. After every run i would keep them at 50 psi. It was better then the first day, but still was a lot of roll over.
We got 6 runs and by the end my tyres were gone. Going into this event i had about 50000 miles on the tyres and that is over about 3 or 4 years of use. Not really sure, they were on there when i bought the car in July of 2003. Time for new tyres, not sure what to go with, i might go with the Goodyear Eagle F1 GS-D3's again, a lot of miles, quite, good in the rain, over all i loved them.