gulf911

Hello,

did I understand you right when you said you are running stock alignment with Hoosiers?
Any issues running hoosiers with 19's (forgeline offsets) and -2 camber front , -1.7 rear?
I am being told hoosiers need huge camber.

sharkster

Glad this thread got bumped as I really didn't see this originally. I think these lil' mods you/we do really do wake up this lil croc. To me the engine felt a little anemic and lacking in response in stock form.

BGB Motorsports

Well yes and no. The Cayman is what needs camber because it's a strut car in the front and the rear and when it rolls in the middle of the corner it loses camber on the loaded side; therefore it needs more static camber so at the max G load section of the corner the contact patch of the tire is maximized. The reason Hoosiers need more camber than a less sticky tire is because they generate more grip and therefore more body roll and therefore require more camber. I had left the alignment alone because i wanted to drive the car with the bar full soft up front, full stiff in the rear and the car lower just to confirm for my own personal curiosity that the stock alignment setting wasnt enough for max grip potential. It needs more camber. We usually run 2.75FR/2.25R on these dual purpose cars.

Thanks! If you think the car wakes up with the mods you've done thus far, check out my car vs. a stock car.

gulf911

Holy crap... Might I ask what total cost would be to get those numbers from a GT4? Including install.

Thanks,
Dan

BGB Motorsports

Its been 1 year since I wrote this. I went back to the same event on the same 7K mile tires with the same alignment settings and only my Stage II power mods that generated the dyno chart above. This time i took Marc D with me as a passenger so we have another Rennlist person to offer an opinion. Last year's top speed was 163mph with a 2:04 lap time. We just did 171mph and went 2 sec faster with all else being equal. I was getting point bys from 302Rs, Vettes, GT3s and a guy in an R8 Audi wanted to know how I towed him around the banking with my little ol GT4! Power mods make this car awesome. For data purposes our GT4 Clubsport MR is 5 sec faster and 6 mph slower at terminal velocity!!!


Hi Dan,

My apologies. I never saw this reply. I can PM you on Monday if you are still curious; if however you have found a different plan to pursue, I understand entirely.

IPSA

How much rear toe and is that dependent on amount of rear camber?

Thx

BGB Motorsports

The alignment is 100% stock. Even my passenger wondered if it was modified. To me it feels like there isn't a lot of rear toe based on how quickly it rotates. If you have aftermarket parts in the form of toe links, how much toe you want to run is at your discretion. It's when you add camber that you're limited to how much camber you can run because the stock toe links can't be lengthened enough.

MarcD147

this thread was a bit further down so I didn't see before typing it but my review is posted here: https://rennlist.com/forums/gt4/9665...s-weekend.html

IPSA

Do you agree with adding more static toe, up to 6mm as opposed to stock 3mm, to deal w tail wagging under heavy braking?

myBailey07

Yes, going from 3mm to 6mm cured brake dancing issue as well as corner entry snap oversteer tendency.

Snowman.

That's a decent real world increase. We recently went to Bathurst and down Conrod we had 1 car with just sports headers (no tune) pull 255km/hr (160mph) and another with full race exhaust, IDB, TB, filters and Cobb tune that ran 260km/hr (163mph). Otherwise the same cars / rubber etc.

It was at that point I decided all that extra cost etc wasn't worth it for such a small real world gain. But your gains are far more significant.

BGB Motorsports

The Hoosiers are very grippy and therefore generate more body roll so they would require more camber than stock. I ran them with the stock alignment because I was at 2 tracks that were low grip tracks in the summer. To take full advantage of them camber should be added; not running the camber would eventually result in premature wear on the outside shoulder. (sorry for the delay by the way.)

Does your snap oversteer start with understeer? Running more toe increases tire temp but it's pretty negligible and if you're looking for that rear end stability under braking, additional rear toe in will absolutely help. The issue you will run into though is when you track down to the apex and apply power the rubber inner control arm bushing is going to deflect and you may end up with even more toe in.

Thank you for the positive comments. I can only dream of what it would be like to run Bathurst; what a pheonmenal track. I've lapped it in the sim but nothing would compare to real life and those narrow walls all over. It's easily one of the top 5 all-time race tracks in the world. How much do you have to lift for that kink after coming back down the hill and how much mph are you carrying then? 163 was the best we could muster last year, maybe 164 and i went back out Sunday and with a full tank of race fuel i could run my more aggressive map with more timing and was able to go back over 171 again.

Snowman.

Bathurst is every bit as good as you imagine it is. I've driven a lot of the big euro tracks (Spa, Ring, Portimao etc) and I still rate Bathurst as my favorite. You don't have to lift for the kink - in pretty much most cars. However - the big issue isn't the corner but stopping afterwards. In the sims you always have more stopping ability than reality at that track. So I'm flat through the kink but on the anchors as soon as it's straight. So in the end the kink is only NOT flat if you can't stop in time. Which is the case for a lot of cars.

And that's where the 255km/hr (160mph) was (on Trofeo's - I was a little higher on Hoosiers).

Real world vid for reference (Hoosiers).

John@Fabspeed

Awesome video Living the dream haha

Warwick Morris

Hey Snowman, just saw this now. Great video and you were maintaining serious (read scary) speed across the top through Sulman/Reed Park. The point at 1.11 sec in is where I crashed at Easter in the my old GT3. Cool tyres (first race lap after warm up), one little understeer into the near side wall, rear then swings-in and hits, breaks toe link, rear left wheel points across the track, car follows, correction (???), rear right hits opposite wall in massive hit, car steers back across track and soft hit again on front left. car stops just where the grass verge starts (with small oil fire). Initiation speed just over 140 kph. Result one bent GT3 (undergoing ground up resto) and two broken ribs (ouch!). Yes BGB, the walls are close.
I did the regularity in the GT4 on Sat and Sun and practice was free. My official trap speed in practice (no trap speeds given for the main runs) was 252.9 kph in totally standard car. I’m having the IPD plenum and GT3 TB installed next week; will take mods bit by bit as Porcshe Club NSW competition pans out in 2017.