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I have my tire temp data, taken last week at NJMSP: Lightning. I did these by myself and after a normal cool down lap and pit in, so the temps are way low, but their relevance to each other is telling.
To my understanding, when properly set up the outsides should be 10 degrees cooler than the insides and the centers should be the same to slightly cooler than the insides.
Clearly that's not the case here. The outsides are as hot if not hotter than the insides and the centers are little warmer than the insides (left side). Conclusion: Not enough camber at (-1.7). I knew that, but good to have data that supports this as I am a data guy.
My car goes in for an alignment Monday (+monoball LCAs and adj thrust bushings in front and then I am back on track (WGI) Weds-Sun, so I should get some more data on the new alignment within a week or so.
I am thinking of going with the BGB recommended alignment for the GT3, which is -2.7F, -2.4R, with 1.5MM Toe out each F, 3MM Toe in each R, and Caster at 9.5 degrees
I am comfortable with the camber being a little conservative, but am less sure about the toe and caster. These are known good settings for a GT3, but of course the RS is wider and runs bigger tires, so I don't know how well they will translate. I will report back on handling, braking and tire temps after next weekend.
As for sway bar settings, the first three days at the track are advanced days, so if we have good weather, I will start with middle/middle, then after a good couple of baseline runs, try rear stiff/front middle, and swap them to see which helps/hurts. Will try to take some tire temps there as well.
I'm pretty sure you need at least as much camber rear than front.
I'm pretty sure you can do toe zero front, that's a lot of toe out.
and a lot of toe in rear. Im Zero and -1mm in each side rear, id go -2mm each max.
I tried toe out as per GT3 setup and it didn't work, based on GT3 setup I tried I think GT3 setup doesn't apply due to front grip and rake. And it shows by wearing rears more than fronts on RS as opposed to GT3.
And please try rear bar stiff, it worked well for me.
On the GT3's I have been told that you need to replace the thrust arm bushings in order to get more than -2.2 of camber and still maintain caster. I assumed this was true for the RS as well, so I ordered LCA Monoball ends and adj thrust arm bushings before getting my alignment. I first ordered them from RSS and my mechanic said they were not right. I then ordered them from Tarrett and they are still not right. According to my mechanic, the thrust arm bushing is just a little too thin and the bolts on the monoball end are too short.
My mechanic had a conversation with Ira at Tarrett and is getting this sorted. Apparently Tarret has monoballs with longer bolts that will work and has a shim for the thrust arm bushing.
Anyone else experience these problems? Anyone getting -2.7 of camber with stock parts and no rubbing?
On the GT3's I have been told that you need to replace the thrust arm bushings in order to get more than -2.2 of camber and still maintain caster. I assumed this was true for the RS as well, so I ordered LCA Monoball ends and adj thrust arm bushings before getting my alignment. I first ordered them from RSS and my mechanic said they were not right. I then ordered them from Tarrett and they are still not right. According to my mechanic, the thrust arm bushing is just a little too thin and the bolts on the monoball end are too short.
My mechanic had a conversation with Ira at Tarrett and is getting this sorted. Apparently Tarret has monoballs with longer bolts that will work and has a shim for the thrust arm bushing.
Anyone else experience these problems? Anyone getting -2.7 of camber with stock parts and no rubbing?
tarettes thrust bushing is correct. and it is thinner, you need spacers for it and tarett has them.
I managed to get an official document from Porsche (in German) about the issues with touching the wheel arches. They suggest:
-respect geo and suggested ride height
-remove front fender grills on track -> I hadn't realised you need to remove wheel, calliper and sensor to do this. Is this correct, or just Porsche's recommendation?
-remould inner rear arches with warm air -> they do warn about possibility of cracks in the paint. So will ask if I can just get the new mould off the rack, if available.
My German is not perfect, so would be great if anyone can get this document in English from their dealer.
I guess stock camber (-1.7) is not enough. I need more camber in the rear. Just starting to cord the outsides with lots of good tread on the rest of the tire. Corded with close to 7/32s remaining.
I followed trakcar's advice to set rear ARB bar to full stiff (from middle) and front to middle, and first indication after half day on track is very positive.
After 8 track days with stock suspension, 36 sessions, I feel that I have a good baseline, particularly at Watkins Glen for 5 days.
Car goes to the shop next week for alignment. My mechanic worked with Tarrett to get the longer bolts on the monoball and the shims for the thrust arm bushing, so I think it will all fit now.
Based on what I have heard here, and my tire temps and tire wear patterns (cording RL) I think I am going to modify my original thinking and go with the following:
Camber -2.7 all around
Caster 9.0 (which is basically where it is from the factory, just cleaned up left to right)
Toe: This is the less clear one for me. 991GT3 guys say Toe-out 1.5MM each front and 3mm toe in on rear. But here, RS guys are saying zero/near zero toe in the front. I think I am going to go 0.5mm toe-out on front, 2mm toe-in on rear, which balances left/right from the factory for both front and rear (factory as measured was FL=1MM out, FR=0.5MM in, RL=1.7MM out, RR=2.5MM out)
Ride height: I will leave it alone until I see how much clearance I have with new alignment.
Happy for your thoughts.
Sways: I have not touched them yet, as my alignment was delayed due to finding the right parts, but will try moving from Med/Med to Stiff/Med and Med/Stiff. I will also play with the wing settings at the track.
I am at WGI for five days in early June, and will report back.
I guess stock camber (-1.7) is not enough. I need more camber in the rear. Just starting to cord the outsides with lots of good tread on the rest of the tire. Corded with close to 7/32s remaining.
That looks like contact with the fender lip.
My car arrived last week with rolled rear fenders from the factory.
04-30-2016, 02:27 PM
Tire Temps
