Time Attack Suspension Setup

[Full-Race Geoff]

hello resident suspension experts, I have decided to turn my GTR into a time-attack machine for a big race event coming up (modified tuner shootout). it will go back to street car duty afterwards, but i am working hard to make the car competitive for the event. We got 2nd place the last 2 years in street subarus and we dont want to give that up. A street subaru wont get us 2nd this year - there will be a dedicated track porsche 911 twin turbo awd as well as the sierra sierra cosworth evo so we have to be on top of our game to do well.

The chassis and engine are VERY solid and have plenty of time with no problems. Specs are:

full roll cage, proper bracing in the right spots

r34 gtr brembos, pfc 01 pads, brake ducting

R32GTR front suspension, caster changed to 7degrees through custom upper mounts. Stock swaybar, Stock Upper Arms, Stock lower arms, Stock tierods, Quaife Front LSD, urethane swaybar bushings

R33GTR rear suspension, full adjustable links, R32GTR stock swaybar, nismo LSD

Tires are Hoosier A6 (Autocross compound for time attack) and BFG R1 (enduro + lapping) 275/35 on a 18x10.5

Torque Split is running fixed with 40-55-60psi in the transfer case (ATTESSA eliminated) depending on preference

built motor, single twinscroll turbo, 680hp on E85 (helps response), good oiling system and cooling

I am getting a set of triple adjustable motons, and they will be used only for the track (will switch out to my koni 28 series for the street). Curious on what you guys have used and i may also end up picking up some ohlins since i was offered a set at too good a price to pass up.

Please advise on swaybar, roll center adjuster height, tie rod changes, spring rates, alignment and anything else pertinent. We are taking care of aero and improving the cooling right now, will jump on susp middle of next week, need to make some decisions. thanks for reading

Edited January 24, 2010 by Full-Race Geoff

[phunky_monkey]

Hey Geoff, try posting this up in the Motorsport section mate, may get some responses there from people who actively race their GT-R's.

Dane

[djr81]

Got a bit of work to do in a short period of time then....

Torque Split is running fixed with 40-55-60psi in the transfer case (ATTESSA eliminated) - this will make things interesting. Can I ask why you chose to do it that way?

Cusco make good, (albeit fixed) sway bars. I would recommend one for the rear, not so much for the front where softer offerings may be better..

Spring rates are dependent on where you are running (ie what track) but also (importantly) on the Attessa set up. With a fixed set up you could arguably afford to increase the rear spring rate relative to the front to help remove understeer.

[Beer Baron]

first recommendation is brakes. you will need something at least 355mm front rotor with some bigger callipers (bigger pad area) than the stock 34 GTR brembos if you want to compete with cars like you mentioned.

[Full-Race Geoff]

Hey Geoff, try posting this up in the Motorsport section mate, may get some responses there from people who actively race their GT-R's.

Thanks dane, just posted up and added some pics http://www.skylinesaustralia.com/forums/Ti...tr-t306963.html

first recommendation is brakes. you will need something at least 355mm front rotor with some bigger callipers (bigger pad area) than the stock 34 GTR brembos if you want to compete with cars like you mentioned.

thanks for the advice. unfortuantely the money is blown on the aero package and motons. the r34 brembos will have to do, we got a SUPER aggressive pad that should shred rotors so well see what it can do

[boxheadmr]

From the looks of things you are running a full GTR driveline and engine combination in a S chasis car, this is fairly custom set up and there would have to be some differences from a normal GTR or S chasis car so doubt you can't use the exact same suggestions for these cars.

What is the results on the corner weight scales?

Edited February 5, 2010 by boxheadmr