good hands

Great suggestion. I'll also suggest that If you don't want to buy new and you just want to test fitment and get in some practice laps you may want to buy scrubs from this guy to test with http://www.jbracingtires.net/hoosier.htm
He has those sizes in stock and I paid 100.00 per tire. They had plenty of rubber to practice on.

Maybe JR can chime in on this but I beleive the Hoosiers and the Yokes like different amounts of camber so I would hate to see you spend money on new tires only to have them corded or wear badly. I tried the both brands at Sebring and ended up cording the Hoosier where the Yokes wore very evenly.

Yellow996

JR:

At your suggestion, I contacted Woodman. They suggested the 235/645 and 285/645 set-up with R80 in front and R100 rear. If you think the 8s can handle the 250s, I'm willing to give that a try.

To answer your other questions, spring rates are 1,000 and we're running 3.2 front and 2.7 rear camber.

Scott:

Thanks for the info on a scrubbed tire source. By the way, your car is too fast...please go back to "I"!!

good hands

Were you at Sebring ? You need a pic of your car as your avatar. Us 996 guys have to stick together in GTB. The Caymans are everywhere !

I think I've talked my other 2 996 "I" buddies into following me into GTB.

MarkM

Is that where all the I guys went? A couple of years ago I thought I choose wrong in going with an H car, as the I fields were growing.

According to Rennpoints there were only 12 I drovers last year (excluding 13's)

Yellow996

Yeah, I was at Sebring. Last year was my first year with the car and first year racing, too. I did WGI, NJMP and Summit Point last year. I was car #45 at Sebring. I'm an RTR member.

I will get an avatar posted soon.

I think John Giannone is making the switch from I to GTB1, as well.

jrgordonsenior

Bet whomever you spoke with has never driven an understeering 996. You ran 245/35 R6's, that the exact same tread and section width as their 250/650 slick.
The slick's is almost an inch taller, but should fit with -3.2 camber up front. I would roll your fenders regardless. I finally threw away the R100's I tested with 20 HC's. There was still lots of rubber left, but they were bricks. I think they're just too hard unless you're a cup....

Are you really running 1,000 lb. springs both front and rear? I run 550/700....

KaiB

JR - I'm gathering that you would recommend R80s on all 4 corners of my car then.

309hp to the wheels and 2550# driven (I also prefer a softer spring).

jrgordonsenior

Yes R80's all around but I'd try the Yoko's first.....

Is your 309 WHP? That is a good number if WHP....

jakermc

A word of caution on the Hoosier 280/645 tire on the rear of mid and rear engine cars. We've been experiencing an alarming number of blow outs related to sidewall/tread separation, so frequent that I have dumped using the Hoosier slick altogether.

Last year I worked very closely with the Hoosier rep on the problem, spending 4 weekends together at the track and monitoring pressures, temps, etc. on my Ferrari 355C. His recommendation was to run the taller sidewall, which I tried and hated in that car. The other work around was to increase tire pressures fairly significantly. Bottom line, he felt that the short sidewall was not suitable for mid and rear engine cars at what I consider to be the ideal air pressures required for the best lap times. Hoosier was the spec tire for the series in 2012 and the drivers were so unhappy that the entire series is moving on to Pirelli for 2013. Unfortunate because I really like Hoosier's customer service and support, I would choose them if I could. I just don't feel like the product works right now.

This is a relatively new phenomenon. I ran the tire successfully in 2010 and won the NASA regional championship on them. But something changed and my experiences the last two years have been horrible. As have others I've been running with. It's not fun when a tire explosion takes out your rear suspension at 90+ mph.

KaiB

Gotchya, thanks.

Yep, 335 flywheel and 309 to the ground - with stock pistons!

jakermc

That's a lot of lead you'll need to add to run GTS4 with NASA! Will you run a restrictor to remain in compliance there?

My stock air cooled 3.6 just dyno'ed at 257 rwhp. You've got a nice build there.

KaiB

With GTS4, I can come off track at 2628# - with 40# of lead and fuel, plus the coolbox I can do that. PCA GT4S comes in at 2677#, so more lead and fuel - it's far more fun to run light and GT3 - but supprisingly not that much faster. I think a GT3R configuraton would be fun.

I'll only run one NASA event this year - the June "Nats" at Hallett, so we'll wait to see who shows up (!).

jakermc

So R-compound instead of slicks with NASA, makes sense. I think the penalty for slicks is steep in NASA and if you can, a lighter set-up on A6 rubber is a better combination. Matus has proved that over the past few years.

I am hoping to be at the NASA event at Hallett in June but I will be in my GTS3 car if I do make it.

good hands

Your car looks awsome. Yellow is a great color for our cars.
Yeah I have been talking to John about weight savings. He is definitely making the transition.

FYI If you were running r6's at Sebring I would say that slicks are about a 2 second savings there.

I have 289 at the wheels ( last dyno ) and weight is about 2970 with me in it. I can lose another 70lbs for GTB1 but I feel like I am in no man's land when it comes to NASA and I just don't have the funds to buy both R comps and slicks. I guess some guys must be doing both.

Yellow996

Yes, I was running R6s, had some transmission and brake issues, plus first time on Sebring....Yeah, that's about all the excuses I can come up with for now! Best lap was a 2:25 and change, but my crew guys were wandering up and down the grid looking at the other GTB1 cars and telling me on the radio, "Slicks, slicks, slicks, slicks, etc."