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Wow seriously-3 on stock mpsc2 or Dunlop -3? On street 991 gt3 and RS? Even on my 997 street cars on streetable Nitto nt01 -2.5 was max front and what I have noticed and others is 991 chassis seems to require less . Not arguing against Manthey but -3 is a first and hearing any stats on there secret sauce alignments
There is usually a difference between max performance and max tire life, in terms of alignment values. Manthey is typically setting up cars for all out, maximum track performance. They also often have customer cars with aftermarket suspensions with stiffer springs, and/or stickier tires like Trofoe-R. They are in the business of lap times. I've run very aggressive setups on Cup2, and while the ultimate tire life is compromised (a bit more inside wear than outside), on-track performance simply cannot be denied. The car is faster through corners, and overall. When I went from -3.3F/-2.7R to -3.5F/-3R the car got faster. Did the inside of the tire wear faster, yes, but I also drove to the track on them. My car, compared to a stock alignment GT3 at NCM on same tires is a lot faster, and that's mostly due to alignment.
The Manthey .1RS on KW Clubsports ran -3.4F/-3.2R on Cup2 tires, FWIW. That car has similar spring rates to the stock .2RS.....which is why on another post, somebody direct from Porsche motorsport, at the factory, with a pro-driver, gave a Euro-delivery owner an alignment setup sheet for "aggressive track use" on a .2 RS as -3F/-2.5R on stock rubber. That's straight from the factory.
I'm like everybody else here too, I'm just trying to figure out alignments that don't eat $2000 sets of tires in 2 days, but damn it's tricky with this chassis. Have Trofeo's mounted up and getting ready to test -3.2F/-2.6R and adjust from there......the problem, IMO, is that while the car probably needs more rear camber (closer to the front value), doing that induces more understeer (especially on the non-RS), so it's compromise no matter what you do. I have adjustable shocks, so if my rear tire wear is still crap at -2.6, then I'll just keep increasing it, and also increase rear shock stiffness to see if that works instead.
Interesting - note the Road America settings as picked up by Stout direct from Porsche. These settings were used to generate the lap records for both the GT2 RS and GT3 RS - perhaps they went less aggressive to ensure they could do enough laps to get the record in the bag with a set up that is the best "all rounder"
FWIW the most I have ever run is -3 square but that was on an EVO9 used for time attack. Would eat two sets of tires in one day.
Mdrums the interior of my RS is black with silver stitching. Will an aggressive alignment affect resale more than removing the headliner and sun visors for the full cage? 😀
Well, on OEM Michelin’s, I found the more camber I added, the slower the car.
Makes sense when the grippy part of the tire is on the outside.
And it didn’t improve tire life.
The tires cord on outer edge, so more camber should make tires last longer.
On a stock car my experience doesn’t make sense with Manthey throwing so much camber at the car..
They know but...
Yeah, I've been scratching my head at alignments since I've owned the car.
I'm going to find a setup for my Trofeo's and be done with it. I honestly don't care if it's faster or slower, as long as they don't prematurely wear out on either side...…
Trofeo’s are built different from MPSC2 and Dunlops..
From what I think I know today is that the Dunlop is faster, last longer and is easier to tune then the MPSC.
Trofeo is / was? Faster but doesn’t last as long unless lots Camber, then maybe..
I realize this is a setup thread for the RS but it's helpful that there's some GT3 stuff leaching in.
I got five days on Trofeo Rs at Road America (including driving to the track from home and back) and found the outside wear to be quite acceptable with -1.8 (front) and -1.5 (rear) camber. For the last event there in October I'll have -2 up front and will likely bring the rear to match to see how that feels.
I realize this is a setup thread for the RS but it's helpful that there's some GT3 stuff leaching in.
I got five days on Trofeo Rs at Road America (including driving to the track from home and back) and found the outside wear to be quite acceptable with -1.8 (front) and -1.5 (rear) camber. For the last event there in October I'll have -2 up front and will likely bring the rear to match to see how that feels.
5 days, nice! I can see how a less aggressive camber setup would work pretty well at RA. Probably somewhat similar to Sebring. I think a decent amount of the data/info is fairly interchangeable between models, or at least helpful for us non-RS guys. My car is more stiffly sprung (~685/1150 #), so it will always require more camber than stock, but it definitely helps for reference.
Since I'm coming off a more aggressive setup, I'm just backing off slowly from the other end, trying to negate inside tire wear. Same process, just working from the other side of the tire!
I finally got my ride height numbers as delivered by the factory and after 15,000 miles and 30+ track days the suspension is pretty well settled.
Front 127mm. Most all .2 GT3RS came with 124-127mm front ride heights. Give or take 2mm.
When compared to the average .1RS that is 12mm higher than the ride height of the .1 GT3RS as factory delivered.
Rear 275 mm. Most all .2 GT3RS came with 275mm. Give or take 2mm.
So it looks like the car can maintain rake and drop about 15 mm, quite a lot.
But the front end is so good, I will leave it alone to start and see what it does.
Camber was 1.5F and 1.5R roughly
Sway bars middle
zero toe front and 2mm in each side rear.
Setting up the car first time and start playing with it at Sebring:
No change to ride height.
No change to toe: Zero front, 2mm in each side, as delivered from the factory.
No change to sway bars: Middle front and rear to start at Sebring
-1.5 camber front and -2.00 camber rear, so just adding -0.5 degree to the rear.
I will try to put a day together to try Michelin, Dunlop and Goodyear tires before I make setup changes.
Just for curiosity could you measure (and maybe post a picture) from floor to wheel arch?
Of course not right way to measure but just to easely compare as I did not manage to really precisely measure from the recommended points
My 991.2 gt3 rs is actually around 715mm from floor to rear arch and 689mm from floor to front arch (and about 109mm front and 268mm rear from recommended points) but I find it a little too low and want to raise it about 5 to 10mm
BTW just went to change brake pads and adjust ride height a lillte less low and found that the front left weissach package carbon arb link was broken...
I did not went on the track at all yet
Could it be because of the lowering?
Or just a defective part?
Still never saw that happen to a metal link and in that case the use of carbon fiber for that kind of part on a street gt car is questionable...
Maybe better to buy some aftermarket adjustable ones?
08-21-2019, 07:16 AM
