Randy Pobst- ZR1 v 2RS
10-17-2018 | 12:40 PM
#46
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Joined: May 2012
Posts: 13,427
Likes: 4,632
From: Mid-Atlantic (on land, not in the middle of the ocean)
The balance in terms of oversteer vs understeer can usually be adjusted with sway bars, etc., but I think the issue here is the extent of 'snap' oversteer due to throttle lift, trailbraking, or throttle application, rather than progressive, predictable, and controllable oversteer.
10-17-2018 | 07:58 PM
#47
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Joined: Sep 2013
Posts: 846
Likes: 287
From: U.S.
The GT3 RS is extremely sensitive to alignment.
I have driven my 991 Turbo S with a rear wheel on toe-out, all the toes mismatching, and it is still driveable and no harsh driving manners, not twitchy or anything.
My 991 GT3 RS feels twitchy on corner exit, then goes to the alignment rack, and rear toe is out of specs. I run another 0.05 degrees of toe-in at the back compared to factory specs, massive camber (-4.0 front -3.2 rear), the car is pretty sensitive to alignment. This was the same with my previous GT3s (996 and 997).
Ride height adjustments throw away the alignment specs as well, toe/camber/caster are changed when ride heights are adjusted.
The GT3 RS suspension takes a while to finally settle. Mine didn't settle until the car was closed to 3,000 miles. I set the ride height at 1,100 miles and haven't moved the spring perches since. However, the car chassis ride height dropped over time by 13mm in the front and 11mm in the rear, not making any adjustments. This is documented by Porsche already. I now need to increase the ride height, as the car is rubbing on every corner on normal road trips (my spoiler lip is 28mm to the ground on a totally stock suspension).
Take a newly delivered GT3 RS to an alignment rack, and 99.9% of the time the alignment specs will be off.
I spoke to Randy at an event last month, we spent a good 30 minutes among car enthusiasts talking cars, and we had a brief 991 GT3 RS conversation (including the Purple car at Laguna). His main comment on the 991.1 GT3 RS: that's a race car. Yes, he said again that my car (I was showing him a picture) oversteers, and I agree but only when driven badly, or badly setup (alignment, ride heights, tires).
The RS is not the fastest track day capable street car, but it is the most fun street car on a track day (and I don't think the fun factor can be matched by the 991 GT2 RS).
I have driven my 991 Turbo S with a rear wheel on toe-out, all the toes mismatching, and it is still driveable and no harsh driving manners, not twitchy or anything.
My 991 GT3 RS feels twitchy on corner exit, then goes to the alignment rack, and rear toe is out of specs. I run another 0.05 degrees of toe-in at the back compared to factory specs, massive camber (-4.0 front -3.2 rear), the car is pretty sensitive to alignment. This was the same with my previous GT3s (996 and 997).
Ride height adjustments throw away the alignment specs as well, toe/camber/caster are changed when ride heights are adjusted.
The GT3 RS suspension takes a while to finally settle. Mine didn't settle until the car was closed to 3,000 miles. I set the ride height at 1,100 miles and haven't moved the spring perches since. However, the car chassis ride height dropped over time by 13mm in the front and 11mm in the rear, not making any adjustments. This is documented by Porsche already. I now need to increase the ride height, as the car is rubbing on every corner on normal road trips (my spoiler lip is 28mm to the ground on a totally stock suspension).
Take a newly delivered GT3 RS to an alignment rack, and 99.9% of the time the alignment specs will be off.
I spoke to Randy at an event last month, we spent a good 30 minutes among car enthusiasts talking cars, and we had a brief 991 GT3 RS conversation (including the Purple car at Laguna). His main comment on the 991.1 GT3 RS: that's a race car. Yes, he said again that my car (I was showing him a picture) oversteers, and I agree but only when driven badly, or badly setup (alignment, ride heights, tires).
The RS is not the fastest track day capable street car, but it is the most fun street car on a track day (and I don't think the fun factor can be matched by the 991 GT2 RS).
10-17-2018 | 09:27 PM
#48
Advanced
Joined: Apr 2014
Posts: 76
Likes: 0
From: Atlanta
I tracked my .2 3RS for the first time at Road Atlanta yesterday and at 7/10ths the car felt perfect. The only thing I changed was the wing for max downforce and removing the plastic pieces from the front. Driving at 10/10ths might bring out a little oversteer. Hopefully I'll get it back out there soon.