Who is running them and what spring rates - coil overs and/or regular springs?
Right now I am running 800-820 linear (calculated). thanks
pics
Right now I am running 800-820 linear (calculated). thanks
pics
315's on the front?
- Thread starter Venom525RWHP
- Start date
Are you running them? 315s on the front is a bit much IMO.
No, I just put them on to check clearance. My springs are too soft, they will rub the fender under hard braking.
I need to shave atleast a sec of my time to be on top next year and since the R1's worked so good on the back I want to try and run them on all four corners.
Other mods will be a torsen diff with 3.90 gears.
for this type of racing on this oval.
Ported Eaton 03 Cobra racing on an OVAL!!
For street yes, but for open track wider is always better, mustangs are so front heavy that the wide meats help it get pointed in the right direction. I'd love to have 315's all four corners or 315's front and 335's rear.
.02
i remember this thread on socalterminators where there was talk of putting 315 all corners, fwiw :beer:
http://www.socalterminators.com/forums/showthread.php?t=13283
http://www.socalterminators.com/forums/showthread.php?t=13283
If you can do the job with a narrower tire, why add the extra rotating mass? Sure....its cool.
actually i saw something pretty interesting on my first day of a road course, an instructor driving a c6 z06 was running 315 slicks all around and at some point he kept mentioning tires rubbing so for lunch he swapped out to 295 (dont know if it was just fronts 295 or rear also) but he shaved a second off his lap time.
his point that he was telling me was just because you have bigger tires doesnt mean you will any faster or grip better, there is a certain size that will be best and anything wider then that will make things worst.
295
255 /\ 315
kind of like that as he explained it to me, theres a low thats the worst, theres a perfect then things just go down.
his point that he was telling me was just because you have bigger tires doesnt mean you will any faster or grip better, there is a certain size that will be best and anything wider then that will make things worst.
295
255 /\ 315
kind of like that as he explained it to me, theres a low thats the worst, theres a perfect then things just go down.
Of course, there comes a point where mass and weight overcome grip and strength of stock parts/spindles/hubs/tie rods/ ect ect. If this WASNT the case, we would all be running 335s all around. Bigger isnt ALWAYS better. Remember, you have to turn those huge ass wheels at some point, Id rather turn a lighter narrower wheel any day compared to a 315.
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I posted that over at socalterminators.com. I had to raise my car up a little but it is still about 1" lower then stock. I am running 400lb front coil-overs with ccw wheels with about 6 1/2 " backspacing with a 5/16 spacer to clear the brembo's. I have not found the limit of the front tires yet but they have improved the times by over 3 seconds. The rotating weight is lower with 315's
then stock wheels and 275's.
The rotating weight is lower because you went to a lighter rim. The rotating weight would be even lower if you ran a more narrow tire. Compound is the biggest factor when it comes to grip on a tire. Are you saying that anything less then a 315 on your front end will limit the performance of your car? In mustangs, the heavy front end will assist the front tires in gripping, while typically its the light rear ends we're more concerned about coming out from behind under us, hence the wider tires in the rear. I dont see the trouble of adding, and paying for an addition(?) inch or so of clearance and (?) in weight if its not needed.
I have had 275/315 "r" tires on my car a couple years and corner enrty speed was slower (understeer)compared to 275 on all four corner. I even had to get on the gas less on corner exit cause the more gas i gave it the more it would plow. I tried to balance out the car by going to a softer spring and smaller swaybar but it didn't help much. There is a point that front end weight is a penalty (over 2200 lbs for a cobra). With 315's the car was hooked up, it would go just about anywhere i wanted it to almost like a different car. With most 03/04 cobra's we need to need to ease on the gas on corner exit with 450tq at 3500rpms and the hp we have makes up alot on the straights. Most 03/04 cobra guys are more concerned about the front end understeering. With how the car handles now i don't mind the additional weight.
that's right carlos - for the life of me i could not remember your screenname on svtp or would have referenced you
your car set up is awesome man :bowdown:
best color too! :beer:
This is what I am doing soon, getting rid of my cheap ass HEAVY saleen rims that weigh 28 mofo pounds for some CCW's that weigh 20 pounds, therefore I can have 315's on all four corners and still have a lot less rotating mass. A buddy of mine said its like night and day the difference between heavy rims vs. a lighter rim...........and I believe it.
Thanks racebronco2, this was the kind of input I was looking for...
The AFS 17x10.5 have a 6.9 backspacing and they clear the Brembos. By looking at your car in that link the tire stick out pass the fender a little, more or less like mine... I would say around a 1/4?
How much nose dive/susp travel do you have under hard braking with the 400's up front?
My buddy (also a track junky) wants me to go with 600's, but I am concerned about overloading/overheating the tire with a high spring rate and driving on the street. 400's was my first choice.
As for you guys wondering about the 315's, I rented the oval for 1 hour this summer and started testing with fresh heat cycled 315 BFG R1's in the back and a set of 275 Hoosiers treated with 2 coats of Track Claw in the front.
After some small adjustments to the tow in the rear I went 2.2 sec's faster on my 15th lap. She still understeer like crazy, mid corner I would lift just a hair and wait for the front end to come in. But my exit speed was way up.
I am positive that a set of 315 R1's on the front will help me carry a little more speed through the corner without lifting.
Bigger IS better IMHO.
My car handles pretty much nuetral now but i think 600's would just make your car plow. I am not sure how much nose dive i have but the 315 tires have never hit the fenders, i did go flying over a hump in the road and the rear tire scraped a little in back. I do have spacers in the rear to make the stance look better.
I modified my bumper cover so that the front bottom edge is about 1 1/2" wider than stock (only after i hit something and broke the tabs that connect it to the fender). I have the 3/4" forward k-member but if you have the stock set-up you probably won't have a problem with front tire clearance. The cearance i have now with the 315's are as follows,
wheel straight ahead tire to front edge of fender 2 3/4"
" rear edge of fender 4"
passenger side wheel turned so that the wheel is closest to the
front edge of the fender clearance is 1"
rear edge of the fender cearance is 1 1/2 "
wheel straight ahead tire to front edge of fender 2 3/4"
" rear edge of fender 4"
passenger side wheel turned so that the wheel is closest to the
front edge of the fender clearance is 1"
rear edge of the fender cearance is 1 1/2 "
When no to run 315's
There was a discussion with a well known AIX racer. He pointed out that for most mustangs it is best to just run 275's. His reason is most mustangs don't have the power to break the 315 rear tires loose on corner exit and it may slow down the car since you cannot get it to power oversteer.
Corner entry: you want light under steer
Mid corner : braking done and enough power to maintain speed, you want light understeer
Corner exit nuetral steer or slight under steer so that you can gently convert to controlled power oversteer with your right foot
There was a discussion with a well known AIX racer. He pointed out that for most mustangs it is best to just run 275's. His reason is most mustangs don't have the power to break the 315 rear tires loose on corner exit and it may slow down the car since you cannot get it to power oversteer.
Corner entry: you want light under steer
Mid corner : braking done and enough power to maintain speed, you want light understeer
Corner exit nuetral steer or slight under steer so that you can gently convert to controlled power oversteer with your right foot
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Thanks
The only other problem I see, is hitting the swaybar - do you have rack stops or something?
I haven't done anything with the rack.There doesn't seem to be a problem with interference other than the slight rubbing on the fender lining which i just noticed the other day when i was checking the brakes/pads.
Subscribing.. Venom...I'm interested to see how this turns out for you. For the record, if I could run 315's in front, I would. An 03/04 Cobra is quite heavy. An extra few pounds in tires and wheels is insignificant next to the amount of additional grip you get from the 315's. One competitor in my club did so on his LS1 Camaro, with no other changes to his alignment, and dropped an average of two seconds per autox run, where the runs are in the 120 second range.
I'd be interested to hear about your clearance issues and what springs you end up going with.
I'd be interested to hear about your clearance issues and what springs you end up going with.
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