JR944

Good Morning,

I had a student this weekend driving a GT3 RS. What a great car! I continue to be impressed with the 997 vs. my 996 as it can be so comfortable on the street and capable on the track. My car, with a set of pretty decent track dampers is substantially less comfortable on the street.

Anyway.... My student is an almost new driver and has not gone off the cliff of really regularly tracking the car (yet). I drove the car with him for one session at very very reasonable speed just to show him what he's working towards. (By reasonable, I mean something like 40-50% of the intensity that I'd drive my own car). Even at these very reduced speeds, the car clearly showed a strong tendency towards understeer.

This owner is not at the point where he has to decide on a track vs. street alignment, but I'd like to help direct him where to set the sway bars and tire pressure to bring the understeer back a bit. His car is still set wherever it was from the factory and is running the OEM Pirelli's at factory recommended tire pressures.

I'd really appreciate any suggestions. The owner is a great guy and I'd really like to help him enjoy and appreciate his car even more.

Thanks very much,

Joe

BobbyC

A little "push" on the car is good since the owner is new to the car and track. Full stiff in Front and full soft in rear - sway bars - is likely a good starting point for this drover. From the factory these cars came with the exact opposite, full soft Front and full stiff rear. Be very wary of setting up the car with some oversteer tendencies, it can and will bite. Unless of course the drover is very advanced and has very good car control. Ask some of us how we know.

My current settings are:

Sway bars: 1 from full stiff Fr; 1 from full soft Rear
Camber: -2.8 front; -2.4 rear
Toe: 0 front; slight toe-in rear


Best...

Bob Rouleau

My RS came with big understeer. Consequently I went full soft in front and full stiff in the rear. Finally resolved the understeer my replacing the rear sway bar with the one from the 997 GT2. Front swaybar now 2 holes from full stiff, rear GT2 bar in the middle hole.

Hot pressures on OEM tires 34-36 Hot Front and 36-38 Hot rear.

Alignment similar to that posted above except 2 minutes toe in per front wheel and 14 minutes toe in per rear wheel.

JR944

Thanks Bob and Bobby,
I agree entirely that the car should definitely tend towards understeer. It sounds like your two cars came with the sway bars set differently from the factory.

If you guys are comfortable that the car still understeers at full soft front, full stiff rear, I'll help the owner adjust them to that. Sure wish I had the chance to crawl under the car and check myself where the car was set.

Your alignment settings are pretty similar to what I'm running on my 996 GT3.

Thanks,

Joe

C.J. Ichiban

+1 on sway bars being set nearly opposite the normal track needs from the factory.

like bob, I'd try to get pressures at 35 hot in the front and 36 or 38 in the rear. my biggest problem initially was the car's tendency to roll on it's rubber bushings in the rear- it never really took the "set" on the suspension that the tires needed to stay planted during hard cornering. you can probably feel this but until you see video of the car doing it from behind the actual amount is hard to convey.

it's a pretty subtle thing but once I changed out the parts on that, it was a lot better and found that the car was much more predictable. this can be a real issue when the turn sweeps through elevation changes as the rear wants to lift off the tires and can snap oversteer. there is a ton more "confidence" in the car when it's aligned right with solid rear bushings.

the springs are really soft up front from the factory for a track car, so making a slight ride height adjustment (lowering about 9 or 10 mm) can also dial out some diving and roll problems that made initial turn-in a bit vague.

in the 996gt3 I'd see guys running over -3.0 camber settings up front but with the 997 gt3/rs it's really not necessary unless you move off of street tires into slicks or hoosiers (no point in doing that though)

fwiw none of the "track settings" led to problems in my street driving- the car can really soak up bumps!

JR944

Got together for lunch with my student yesterday. The front bar is set one off from full soft, the rear at one off of full stiff. Hmmmm... I suspect tire pressures may have been too high at the track. He's excited to go back and willing to do a more track-oriented alignment after another event. Will report back what I find whenever we get back to the track. 12 inches of snow here today with more coming tonight!
Joe

roberga

have the front lowered to ROW spec. I think it it 112mm. and do the track cambers. Mine are -2.0 front and -2.5 rear with sport cups and it works for me.

997gt3north

- the setup of the 996 versus 997 (to make it turn) is basically the same - but it appears the 997 needs a little less rear camber

- as other have posted above, camber and toe is what makes it work, and then when that is done, the factory's sway settings can be changed for ones desired style

my setup is similar to others above but i like front toe out

f: -2.7 with 1mm toe out per side (front bar as delivered - 1 from softest)
r: -2.3 with 2mm toe in per side (gt2 bar on softest of 3 holes)

as mentioned above, and as you know, tire pressure with the OE tires is critical (the fronts HOT should be max 33, rears 37hot)

- i find it amazing how sensitive this car is to small changes - but it is

- from your students point of view, adding much more front camber is really a free lunch as tire wear with so little front weight is really a non issue - the rears will still wear out first

- my suggestion for him would be to run (-2.4f with 0 toe and -2r with 2mm toe in) and then make sure he keeps the hot tire temps at f=33, r=37

- next step would be gt2 rear bar on soft

- also, if he has irons not ceramics, there are more tire choices and getting a 245/255 tire up front is the last piece of the pie to balance out the car