[FChampOH]

i beat a lotus to get 1st place in ss i had dam good time over all. the power in sport mode is allways there ,i left the stability controll on next time im turning it off. i did have understeer in the the sweepers im not sure why could be tires or that i need a thicker rear swaybar or i just need to improve my driveing style or some combo of the above. this was olny my 2nd time autoxing w the f and i love it more every time my poor tires took a beating! but thats autosports! i also drove up to montreal 8hours in the f flew by the car is so smooth drove on the grand prix track what a blast! did any one else experince understeer? if so what did u do to fix it?

Henry,
congrats on your 1st place finish! I had run a local autocross 1 time here in Dayton, Oh. I finished 2nd to a c6 corvette with Forgeline race wheels and Hoosier race tires. I was on OE tires. I was a little over a second behind him. I have roughly 10 years of autocross experience and gave him everything I had. It's tough to compete against a race tire vs. street tire. Anyway, it was a tight course in most spots and I experienced understeer as well. All you can do with a stock suspension is give up the speed going into a tight corner, hit the entrance-apex-exit just right and blow out of it. Until we see a big front sway bar and adjustable shocks and a good set of radial Hoosier tires on the F, plan on understeer in tight corners. "Slow in-Fast out"

Doug

(Yes, that's an AMC Spirit next to me! What a hoot!)

 

[FChampOH]

I am curious to see what the IS-F would do around the track with DOT track tires not street tires. We already have a disadvantage with the 225's up front and 255's in the back.

I have researched the Hoosier DOT radials and they do offer a 235/35/19 and a 265/35/19 DOT race radial ! Those would be a blast!
As far as the OE Michelins go, they do an exceptional job on the road course. That tire was designed specifically for the IS-F. I have spent time in the IS-F on the Autobahn country club course in IL once during the Lexus round table meeting to discuss marketing the F-Sport acc's in conjunction with the release of the IS-F and again during the F Champion meeting. I've also spent 3 days at the Las Vegas motor speedway road course testing various performance aspects and high speed track driving. My thoughts were that the Michelins exhibit very high grip in high g load turns (long sweepers). A great tire to drive to the track on the weekend, track the car and drive home on it. After a full day of constant road course use, the front tires do show a lot of wear on the front outer edges and do begin to push (understeer) by the end of the day. We did outfit the owner of Lexus of Dayton's car with a set of 2 pc. BBS wheels and Toyo tires. Wheels and tires are both wider than factory. 245's up front and 275's in rear. Really nice upgrade. Here's a couple if shots of it.

 

[FChampOH]

Nice Driving !!
Doug, we should get together next time we have a IS-F Meet thru lexus..

Andy,
I agree!
Doug

 

[FChampOH]

fchamp; thanks for the good advice in ny autox they always have a seprate class for slicks or race tires . stock tires just cant compete! i have heard that haveing a narow tire in front sets u up for understeer and that tires of equal width are better. all the pros who drove the f at the last event all say that the car definitly needs bigger tires .in scca were in ss w the corvets who have giant rubber ! how big can the f go?

If I had things my way..... I would have coil overs with adjustable damping, then you could use scales on each corner of the car to shift the weight around to make it more of a 50/50 weight balance-more neutral handling. I would probably then adjust the shocks to be a little stiffer all around, maybe even stiffer up front (to help battle the engine weight). I would also look at adding a bigger front sway adjustable sway bar. I would then try to fit something like an 18x10 wheel (would probably have to be a 3 pc. wheel) on all 4 corners with maybe 285/?/18 all around in a Hoosier autocross compound radial tire. It remains to be seen if a 285 would fit in the front wheel well. A 285 tire up front sure would provide some bite wouldn't it? This is just me rambling and thinking out loud. If there was enough interest, I do have the resources/knowledge to work on test fitting and possibly putting together a wheel and tire package for track/autocross use. Before I came to the world of Lexus I worked for a major 3 pc. wheel manufacturer for 13 years. Poetentially I could come up with a set of race wheels and tires with the proper offset,brake clearance, bolt circle, center bore and strength to provide to a crowd with enough interest. Something to consider! HHMMM Maybe a good winter project.
Anyway, again my 2 cents.

Doug