Randyc151

Did you say TRAILER! What are you looking at? I really love my ATC. (I should do a whole thread on that. Easy to go just as crazy with the trailer as the TTS.)

A/S

Time Attacks and Time Trials normally have classes and rule sets.

Optima only allows 200tw street tires.

SCCA ony allows 200tw street tires, except the unlimited class and you will need to deal with factory race cars.

NASA allows slicks with a penalty in most upper classes, but again most factory race cars or well built Grand-Am/IMSA/SCCA/etc. race cars will do better than a 991 Turbo S on slicks.

The bushings on the 991 Turbo S are soft and Hoosier R7 (not even slicks) flex them bad enough to lose camber/toe under heavy loads, lap times are better than MPSC2 but they could be so much better with better bushings. The stock suspension and the H&R lowering springs hit the bump stops on the front axle with Hoosiers (braking to turn entry). With slicks this gets even worse. The 991 Turbo S is soft sprung.

I have gone through slicks of many brands (Avon, GY, Yoko, Michelin, Pirelli, Toyo) and DOT-R on many cars, and only use slicks when I want to setup a track record (or attempt to), but I much rather prefer Hoosiers because in most SCCA/NASA real time trials and club races, you win, then you get free tires.

Slicks and the AWD 991 Turbo S make for a fast car, but there is a cost that goes beyond the 3-4 heat cycles of total life you get from the tires, the cost of modifying the car to make them work properly. I have seen quite a few blow outs at Daytona, Watkins Glen, Cal Speedway, Homestead from simply installing grippy tires on stock suspension cars, then having so much flexing on the suspension to cause tires running on the edges rather than on their contact patches, overheat the edges and explode.

The bushings in my 991 GT3 RS are much stiffer, and the dynamic toe/camber changes are minimized on Hoosiers. I already changed all the bushings in the front axle of my 991 Turbo S, and a few in the back, plus custom springs, so the car would work with Hoosiers, and its track performance improved nicely. My 991 Turbo S beats my 991 GT3 RS on lap times, but the GT3 runs better due to lower weight, low power and better cooling.

Steve Cole

Well, the Turbo cars are more targetted at street driving. It's very very common for street cars to need more stiff bushings for heavy track use, that's really no surprise. And of course, you will get more wear as well as more stiff / abrupt ride when you are on the street with the stiffer bushings.

nolimits

Yep, if someone thinks they are going to run Hoosiers on OEM bushings they are wrong. Camber becomes a setting midpoint in a range, it is not a more static set as with mono or spherical bearings. Turbo beats RS any day especially in the right hands. DSC configured properly is fantastic. Had a great time today leaving the RS's and Cup cars behind. Looking forward to the full R7 setup and Featherlite trailer.

pepinozaur

Great thread, really helpful.

Seems my KW springs will come to late for this weekend event, will switch to 265/325 Cup2 on otherwise 100% OEM car, do you guys think I should try to do a better allignment before the track?
And if so, can you please share some specs for F/R camber,caster, toe etc? Thx

nolimits

You will want more camber, starting point 2.6 front at least, 2.4 rear, always get as much caster as possible for stability, front toe 0, rear a little toe. To get that camber you're going to need some suspension parts. So for now just go to the track and have fun. Others have said plenty in this thread too. Also thread of interest see:

Tracking the Turbo

Need4S

What parts do you suggest for more neg camber?

nolimits

Front upper camber plates and lower control arms, rear medium and long control arms. If you lower or need even more camber for Hoosiers you'll also need front outer toe links. Check with a good shop nearby that folks use.

pepinozaur

Ok so some feedback here after I put Cup2, on the local track I managed to smash road cars record, by quite a good margin 1:50.8xx before and now 1:50.1xx, and that in crazy hot weather.
I have seen from morning till afternoon the maximum speed dropping by up to 10kmh !!! And I have managed to do the best time in hot weather.
PS: On Pzero oem, I have tryied just a few laps and managed 1:53.6, guess low 1:52 would have been possible tho.
There was a guy with a gt2rs for the first time using the car and managed 1:51 on Dunlop Sport Race2 tires (OEM)
The old record holder was AMG GTR, I have beaten 991.2 GT3 on Trofeo R (almost 2sec slower), car is really good and now looking to increase grip, will order a new set of rims and maybe change some bushings ( minimal changes only)


I have to admit I am a big fan of OEM porsche stuff, so guys with more experience, can you advise if oem gt3 stuff should work well on TTS?
The second big thing are the RIMS.... As dedicated track rims, I would force and get some R19 to clear the PCCB, I see no reason to use R20 even if Hoosiers are now available in 20".
Using R19, will give us better side wall, so better grip.... more tire choices, cheaper tires and so on... so I am going to ask the guys running R19 over PCCB, any regret doing it? Would you doing that again, or just choose R20 now?

Jean

Love to hear guys enjoying the track all out on these cars. The more I drive it in events the more I love it! There is so much to be done to them and they just keep getting more and more competitive. Then just remove the wrap, change wheels and drive it back home with all the interior comfort.. All that putting 4-5 seconds on any ACR Extreme or 650S or GT3RS.

Jean

You can fit certain GT3 and cup parts when it comes to chassis.. You have great aftermarket parts as well such as Tarrett and others, I have been running under very seriously tough conditions (hillclimb and circuit) for almost 2 years now and not a single failure. Definitely go 19" and try some racing slicks, the driving feel, confidence and lap times are something that cannot be explained, I used slicks with stock suspension and now with racing suspension, they work great regardless. I do have Tarrett in many places though.

As to bushings, if I were to change just a few things, it would be camber plates, and front control arms and that's it. This is just to get the proper alignment settings and the biggest lap time impact. Then you can move to bushings if you want to keep going.

pepinozaur

I did full Tarrett/RSS setup on my 996tt along with cup like aero, 997 gt2rs brakes etc, and of course.. SLICKS... the experience is second to none using them.. still a bit afraid to use slicks on 991TT as engine doesnt run a real drysump setup, but guess will take the risk sooner or later.
Also R19 will allow us to use slicks, and that is another differentiator

I have ordered KW adjustable height springs and camber plates for now, will look more into LCA front as you advised, thanks a lot! I want to keep things as simple as possible for now

Love these cars, they are too good and versatile!

Randyc151

Interestingly, the GT3 crowd is now beginning to show some respect for the TTS platform. Most will concede they cannot run with a properly driven and sorted TTS, which has to kill them.

Unconscionable

As someone who "upgraded" to GT3 RS, I miss my Turbo for the track. All it needed was tires and maybe lowering springs.

longboarder

I use my 991 GT3 as sort of a "pre-runner" to learn the track and then when I want to go really fast I take my 991 Turbo S. haha.