I'm currently running 1.5 with 315 Hoosier A6 tires and want to know if you guys think a little more will help cornering control. I have the IRS adjusters and it is and easy change. I am still having problems with snap oversteer mostly on corner entry. Other specs: Koni shocks 500 front, 700 rear, front and rear VPM bars full stiff, SAI mod, 22 psi front 24 rear, Roush 402-R, Tremac TKO 600, 3.27 T-Bird SC center section. Im starting to think I might conside a torsen diff? Any Ideas? Thanks for your help.
CB
A torsen would most likely make corner exit oversteer worse. A torsen will help the car turn when under power on a tight turn. I doubt on sweepers the torsen helps much. The rear diff should not matter much on corner entry as you will likely be using the brakes.
I would soften the rear bar to full soft and keep the front bar stiff. Do the same on the shocks Stiff front and soft rear. You need to take as much of the cornering burden off the rear as you can. I am also finding running a minimum fuel load really helps tame the oversteer. My best balance is with a 1/8th tank of gas or less.
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Mike
FFR Coupe #340, 2003 LS1 350 RWHP, TKO 500, QT BH, Champ 10 QT pan, 5 Lug and AC, Cobra Disc, SAI mod, Kumho XS 315's x4 ..Licensed for 28k..Just over 30k w/race tires and many mods http://s464.photobucket.com/albums/rr2/mmarshall01/ http://www.youtube.com/watch?v=uHtx7...1&feature=plcp
Build started - 8 Apr 2008
1st Autocross - 18 Oct. 2009 XP Class
2011 and 2012 St Louis region XP Champion
Just talked to Mark Dougherty on the phone and he gave me several recommendations to help cure my problem. All are easy to do with my set up and the way he explained it made perfect sense. If you are having a handling problem I recommend talking to him. I'm stoked about the changes he recommended. Thanks for your replies.
CB
I would check brake bias first. I had two cobra students so far that had too much rear bias (it was only a little too much). All we did was switch ends on corner entry. It seemed at first like they had no ability to drive. I was a simple adjustment. Check it out.
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FFR3842, Levy Forged 349ci/500hp, AFR185's, Wilwood 6/4 piston Superlites, Koni DAs, Magnesium bellhousing and Tilton Triple disk clutch, GF5R dog ringed 5 speed, 3link, VPM sway bars, Hoosier A6s, CCW forged wheels, wings, undertray, diffuser
Just talked to Mark Dougherty on the phone and he gave me several recommendations to help cure my problem. All are easy to do with my set up and the way he explained it made perfect sense. If you are having a handling problem I recommend talking to him. I'm stoked about the changes he recommended. Thanks for your replies.
CB
Mark is the MAN so listen to his advice.
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MKIII, 347 FRPP 450hp engine, IRS, Full width roll bar, Kirkey seats, Fuel Cell,Leaky Tremec TKO 600, Holley 650 HP, VPM bars, Koni Shocks
1-I agree w/ Marshall, run minimum fuel level. I stay at 1/4 w/ my mustang tank.2- I wonder about your rear bar on full stiff. I try to set bars on a longer constant radius turn to get the balance right there and this usually makes it a little looser than optimim in the quick short turns. So I sometimes change the rear bar depending on which type of turn is predominant that day.3- Your tire pressures seem high. Most of us in the DC area are in the 18front 20 rear range w/275s or 295s on 9 in fronts and 315 on 10.5 rears. What width are your wheels as this might have an effect on pressure.
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FFR 5353K,351/400hp,TKO 500, 3-link w/3.08 and Truetrac, Koni DA coilovers front and rear,APE hardtop,Forte front and VPM rear swaybars
Same width front and back you stated. I have the Team III wheels from Richard Oben. Not sure if our offset is different but I tried the 18/20 tire pressure set up and it seemed to make my problem a bit worse. Next year I'll experiment a little more with shock, sway bar, tire pressue settings. my car is definitely better with the koni shocks then it was with the original Pro shocks. I have 4 of them with 600 lb springs for the Coupe non pin drive if anyone is interested. They have less then 300 miles on them as my Coupe is Auto-x only.
Thanks for your suggestion I will definitely try it.
CB
Snap Oversteer is my problem on corner entry or mid corner when I get back on the gas. Turn in is fine but when the back starts to step out it is almost impossible to recover. Car is tucked away for the winter and I'm going to try a number of changes , as stated above, and see how that works out. I'm planning on going to a test a tune event so I can have some time to adjust the car during the day.
Thanks:
CB
These cars rotate so easy with the throttle, sometimes it is hard to figure out what is going on. I can go into a turn, off the gas early, it will push like a pig. The second I give it throttle I am in oversteer territory. I can go into the same turn, hotter, causing trail brake, now I am fighting oversteer with no throttle. I have learned to rotate the car with the throttle more than the steering wheel.
I never mess with anything, leave the bars alone, shocks alone, tire pressures I check before I leave for the track and maybe double check once while I am there.
CB, if you have problems with oversteer while getting on the gas, try making your throttle linkage less sensitive. Move travel with the pedal, less on the carb. Use the throttle to steer, it works like a charm!
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FFR3842, Levy Forged 349ci/500hp, AFR185's, Wilwood 6/4 piston Superlites, Koni DAs, Magnesium bellhousing and Tilton Triple disk clutch, GF5R dog ringed 5 speed, 3link, VPM sway bars, Hoosier A6s, CCW forged wheels, wings, undertray, diffuser
Trevor: You are reading my mind. I have the modified stock Mustang pedal and when I cut it I thought the ratio of pedal to cable pull was amplified. I'm going to purchase Russ Thompsons pedal which looks to me like a more 1 to 1 ratio of pedal to cable pull if I can make it work. I may also try to move the pivot on my Mustang unit up about 2 inches with a mounting plate and cut the same out of the top and reweld.
Thanks for you suggestion.
Happy Holidays:
CB
One other area to try adjustments is the shocks. Although there is certainly overlap, springs have more effect in steady state cornering and shocks have more effect in transitions. So, since your problem is transitional, I would be cranking more shock into the front and less into the rear. I am not sure if yours are double adjustable or single but it's easy to make rebound adjustments on my DAs and I have played w/ that at times. Go at least two sweeps and maybe three to start cause I am never really sure I can feel one sweep. Too much rebound tends to lift the inner rear tire as you brake and enter a turn so this would be the first thing I would change. I tend to run the rear as soft as I can in shocks and springs. I want to avoid turnin oversteer and I want as much traction as I can get when it's time to get back on the gas.
I agree on the gas pedal. The Thompson pedal gives a nice long travel and I think this is really important
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FFR 5353K,351/400hp,TKO 500, 3-link w/3.08 and Truetrac, Koni DA coilovers front and rear,APE hardtop,Forte front and VPM rear swaybars
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IRS camber for Auto-x
Linear Mode
