Searched various threads and can't find an answer. Running a S197 3V in SCCA CP class. Moved to cp class this year. Complete interior removed, car weights 3144 (no driver). 18x11s with 315 A7s. -3.3 camber with slight toe out. Corner balance with about 30 pound difference on any given tire. Don't have the exact numbers. Coilovers with adjustable swaybar. After about 20 runs I noticed that the front tires are running hotter on the insides (too much camber) and the backs look like 10-15 percent of the thread area on the insides are not even making contact with the ground (no camber) and the tires are rubbing on the rear saybar. Running 30 psi rear and 32 front. Plan to just remove rear swaybar to take care of rubbing. Hoosier says I should run 40 psi at this weight, which I think is too much. Question is should I remove some camber so front inside doesn't get so hot and what is a reasonable tire pressure starting point. Just want to get the potential from the tires and heard that Hoosiers don't like alot a camber. Any input is appreciated, thanks, Dave.
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S197 3V 315 Hoosiers on a S197
- Thread starterBlueGTGS
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not sure, is this an autocross class or a track car?
Then I can go from there
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- #3
autocross
Your camber should be fine. You could possibly need more but certainly not less. You need more in the rear
I think your pressures are in the ballpark. When I ran my car in CP, I used 18x12 with 335 Hoosiers and I am 3500 with no driver and ran 34f/30r. Typically for Hoosiers, at least on the end with camber, lower the pressures until you lose crisp turn in and then go up 1-2 psi from that. This assumes you aren't rolling them over on the outside. It's harder to use rollover on the rears, with no camber in the axle you will kill the edges no matter what. I just used the rear pressure to tune balance and rotated often.
My stock mounted rear bars always rubbed. I switched to Whiteline for a long time and more recently to the Cortex, both of which mount on the axle.
DaveW
- Thread starter
- #5
Thanks for the input, rear camber on the list, just not in the bank yet. I'll play with pressure test this weekend. At current pressures I'm thinking too much rollover.Your camber should be fine. You could possibly need more but certainly not less. You need more in the rear
I think your pressures are in the ballpark. When I ran my car in CP, I used 18x12 with 335 Hoosiers and I am 3500 with no driver and ran 34f/30r. Typically for Hoosiers, at least on the end with camber, lower the pressures until you lose crisp turn in and then go up 1-2 psi from that. This assumes you aren't rolling them over on the outside. It's harder to use rollover on the rears, with no camber in the axle you will kill the edges no matter what. I just used the rear pressure to tune balance and rotated often.
My stock mounted rear bars always rubbed. I switched to Whiteline for a long time and more recently to the Cortex, both of which mount on the axle.
DaveW
What's the thoughts on running no rear bar. Thanks
Do you have a photo of the front tires where I can see the edge? I can't imagine 32 is far off for the fronts given how light your car is.
Removing the rear bar will usually keep the rear tires from rubbing on the bar
If the car's handling is currently balanced with a rear bar, and you remove the bar, you need to add rear spring to keep the same overall balance otherwise the car will be pushyDaveW
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You can get 315s on there but you will have to get creative with the wheel offsets. A standard Grand Am roadrace setup was the Ford " blue" bar up front and an 18mm or no bar on the rear. I forget the spring rates, 600 front 400 rear maybe? It's been awhile. You can heat and quench your rear axle to get camber out of the stock unit, but if you go over about 1.5, you'll need to barrel grind the splines which leads to longevity issues.
A7 hots are about 32psi.
If your car looks like this coming off the corner, you've nailed it.
A7 hots are about 32psi.
If your car looks like this coming off the corner, you've nailed it.
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Bill Pemberton
0ld Ford Automotive Racing Terror
I had a slight rub with my rear sway bar on my Boss 302S ( with 315/30/18 R7s ) and I simply added a 1/8th of an inch spacer and all was solved. Pretty sure you can use a spacer on the rear in CP.
Let me ask you this. Do you like Whiteline or Cortex better?Your camber should be fine. You could possibly need more but certainly not less. You need more in the rear
I think your pressures are in the ballpark. When I ran my car in CP, I used 18x12 with 335 Hoosiers and I am 3500 with no driver and ran 34f/30r. Typically for Hoosiers, at least on the end with camber, lower the pressures until you lose crisp turn in and then go up 1-2 psi from that. This assumes you aren't rolling them over on the outside. It's harder to use rollover on the rears, with no camber in the axle you will kill the edges no matter what. I just used the rear pressure to tune balance and rotated often.
My stock mounted rear bars always rubbed. I switched to Whiteline for a long time and more recently to the Cortex, both of which mount on the axle.
DaveW
The Cortex is way easier to adjust, but they both work fine. I was not unhappy with the Whiteline, it just didn't fit correctly with the Cortex Torque Arm.
A lot of it depends on your overall setup. The Cortex is a pretty small bar, much closer to the 18mm-no bar range. The whiteline is pretty big. You have to adjust spring rates accordingly to make the car work.
DaveW
- Thread starter
- #12
Using a 1/4 inch spacer as is, had to use it to run the 315 rt660s.
- Thread starter
- #13
BTW..
Thread 'diff straightening' https://trackmustangsonline.com/threads/diff-straightening.17210/Do you have a photo of the front tires where I can see the edge? I can't imagine 32 is far off for the fronts given how light your car is.
Removing the rear bar will usually keep the rear tires from rubbing on the bar
DaveW
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Just go ahead and bite the bullet and do the ARP extended studs. You'll be stacking spacers on it sooner or later.
That , plus options are covered in project superbeater.
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Slap a couple of old wheels on it, have a friend hold the tape for you and you can measure any runout as you rotate the wheel.
BTW none will be perfect
You have come to the right place for 315mm discussion, weary traveler...
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- #17
I have arp long studs on all 4s. Plan is to add a 1/8 spacer to the current 1/4 thus 3/8th total and see what happens. I'll just have to watch fender clearance. I like the rear-end alignment post and plan to do that this winter. Will also check superheated. Thanks
That wear shows pressures that are pretty close. My rears looked exactly like that until did the cambered axle. You just have to rotate them often. Your fronts look fine as well.
DaveW
- Thread starter
- #19
Thanks, good to know I'm close.
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