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Tracking the Turbo

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Old 03-09-2017, 05:45 AM
  #46  
gaxor
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One question I have, and apologies if someone has already covered it. Does the rear wheel steering help on the track, and would changing the rear camber affect the rear wheel steering behaviour?
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Old 03-09-2017, 11:01 AM
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Answering your question would require a car that comes with and without rear wheel steering with as few as possible other differences (preferably none).

I'm not sure that currently exists?
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Old 03-09-2017, 01:49 PM
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Originally Posted by gaxor View Post
One question I have, and apologies if someone has already covered it. Does the rear wheel steering help on the track, and would changing the rear camber affect the rear wheel steering behaviour?
Yes it helps; no, it does not change anything in the car set up. Most modern cars have some form of RWS, it's just mechanical/passive.

Passive RWS works like this - you turn the steering wheel, the car leans to one side, the rear suspension responds with a slight change in rear wheel angle (as designed by engineers). So there are 3 limitations - 1) rear steers with a delay (the time it takes the car to "settle") 2) getting the exactly right amount of rear steering is a hard design challenge, which is not fully solvable, so you end up with compromises (too much or too little steering sometimes); 3) the suspension inevitably has more play because of this, although good designs minimize this effect.

Active RWS works this way - you turn the wheel and both front nad rear wheels turn to a precise amount determined by engineers. That addresses the delay, imprecision and suspension sloppiness limitations of the passive steering. But it fundamentally does not change anything - camber, toe etc work about the same.
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Old 03-09-2017, 02:28 PM
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Originally Posted by gaxor View Post
One question I have, and apologies if someone has already covered it. Does the rear wheel steering help on the track, and would changing the rear camber affect the rear wheel steering behaviour?
Short answer is yes. It helps the car rotate on street or track. At low speeds the rears turn the opposite direction of the fronts slightly, thus rotation. At higher speeds the rears turn the same direction as the fronts, helping you hold a more inside corner line if desired. Camber or any alignment changes will impact "behavior" depending on what ones goals are and the configuration of the car. The rear wheels do actually turn with the car static, this system is active. The GT3RS folks can likely tell you more specifically about track steering feel comparisons if you want details.
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Old 03-13-2017, 10:49 AM
  #50  
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My .2 Turbo S has just arrived with dealer and they now install the cage and harness.


Next will be to adjust camber.
Dealer tells me it comes with -1,0 front and -2,0 rear. I suppose rear can stay as is, however, front needs to be some -2,5.
How to obtain this? Will camber plate (Tarett or Elephant) be sufficient or will I also need to swap control arms? I have no plans to lower the vehicle.
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Old 03-13-2017, 11:00 AM
  #51  
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I use Techart springs, and without a camber plate I am getting -1.9 front and -2.2 rear camber. Would like more front, but the car is exceptional with Cup2 tires and these settings, plus Cantrell bar, Cobra Misano seats, and Schroth harness. I also added Awe Tuning wind deflectors, and they really help sound reverb inside the car above 80-90mph.
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Old 03-13-2017, 01:22 PM
  #52  
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Originally Posted by Nordic Flyer View Post
My .2 Turbo S has just arrived with dealer and they now install the cage and harness.


Next will be to adjust camber.
Dealer tells me it comes with -1,0 front and -2,0 rear. I suppose rear can stay as is, however, front needs to be some -2,5.
How to obtain this? Will camber plate (Tarett or Elephant) be sufficient or will I also need to swap control arms? I have no plans to lower the vehicle.
Camber plates will be fine, I would start there, you might get some Caster increase that the control arms can correct if needed, adding control arms is not a big deal.
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Old 03-13-2017, 05:30 PM
  #53  
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Originally Posted by Nordic Flyer View Post
My .2 Turbo S has just arrived with dealer and they now install the cage and harness.


Next will be to adjust camber.
Dealer tells me it comes with -1,0 front and -2,0 rear. I suppose rear can stay as is, however, front needs to be some -2,5.
How to obtain this? Will camber plate (Tarett or Elephant) be sufficient or will I also need to swap control arms? I have no plans to lower the vehicle.
Depends on what tires you will be running. If you're using stock tires you'll be able to get the alignment you need without parts, 2.5 is not needed. Given the cage and harness I assume some tracking, so if you have upgraded tires you'll need camber plates at least as has been mentioned. For mostly tracking you will likely want more camber than stock can adjust to. If they are R compound tires you'll need more camber for sure and other parts due to the deflection of stock bushings etc. Without enough camber you'll have uneven tire temps, and more wear on the outside of tires. Enjoy the ride and congrats.
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Old 03-13-2017, 05:37 PM
  #54  
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Originally Posted by nolimits View Post
Depends on what tires you will be running. If you're using stock tires you'll be able to get the alignment you need without parts, 2.5 is not needed. Given the cage and harness I assume some tracking, so if you have upgraded tires you'll need camber plates at least as has been mentioned. If they are R compound tires you'll need more camber and other parts due to the deflection of stock bushings etc. Without enough camber you'll have uneven tire temps, and more wear on the outside of tires. Enjoy the ride and congrats.
Thanks
I will be running Cup2's, not sure yet if I will go standard sizes (245 and 305) or move up to 265 and 325. My track rims are Forgeline GE1 in 20x12 and 20x9.
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Old 03-13-2017, 05:45 PM
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Originally Posted by Nordic Flyer View Post
Thanks
I will be running Cup2's, not sure yet if I will go standard sizes (245 and 305) or move up to 265 and 325. My track rims are Forgeline GE1 in 20x12 and 20x9.
With the 265/325 Cup2s you'll likely get some inside rubbing at full turn lock unless you get parts that will allow alignment for more caster to go with camber to get the right clearance. Karl911 runs the larger Cup2s I believe.
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Old 03-13-2017, 06:10 PM
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Originally Posted by nolimits View Post
With the 265/325 Cup2s you'll likely get some inside rubbing at full turn lock unless you get parts that will allow alignment for more caster to go with camber to get the right clearance. Karl911 runs the larger Cup2s I believe.
Great info thanks.
Will discuss with dealer, they are experienced in this.

Next issue is pads, I will most likely swap them right away.
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Old 03-16-2017, 09:00 AM
  #57  
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Originally Posted by soulsea View Post
Hi,

So I tracked my TTS four days in the spring.



Now keep in mind that I am an intermediate level DE driver, so the validity of any input I have is limited by my skill and experience levels.

The car has an AWE exhaust but isn't tuned, so no real power gain compared to stock. It is lowered 30mm with techart springs but retains the stock neutral camber, so that may slightly affect its handling behavior compared to stock. The most meaningful upgrade was that I slapped a set of SC2s on her before hitting the track, which obviously makes a big difference and makes the comparison to a GT3 more even. I ran the car in Sport Plus without deactivating any nannies. One last note, I haven't tracked my RS yet so I can't compare the two.

I found the car to handle very well, especially for a car who's primary focus isn't the track. With new SC2s and temps in the mid 70s I didn't find the understeer to be a noticeable hinderance. With the tires wearing and with temps building during the day, by the afternoon of the second day and with tmps in the high 80s, understeer became increasingly worse. By the end of day four the tires were shot and the track was registering 140F, at that point I had to back way off on entry.

Where the car excels, due to its fantastic programming and AWD, is on corner exit (also excellent braking with ceramics). I was setting the same lap times as I did with my C7 Z06. Now the Z06 has tremendous cornering grip, much more than the TTS, but with so much HP and torque and without AWD putting the power down without losing the back is a challenge, and most of the driver's skill is focused on throttle modulation on exit so as to hook the rear tires without spinning the car. With the TTS you can basically get on the throttle a lot sooner and a lot harder than any other car I have driven on track. So much so that my best terminal speed at the end of the straight at Roebling Rd Raceway was 155mph with the TTS whereas it was 150mph with the much more powerful Z06.

Like I said, in the end my laps were comparable with the TTS and Z06, it was just a completely different type of driving. Now for some perspective, the Z06 is well known to be faster than the GT3 around most tracks that have a serious straight, so I would extrapolate that the TTS is also going to be faster than the GT3 with the same driver on equal tires. The issue is going to be for how long. From what I've heard anecdotally the TTS will eventually succumb to heat related HP loss whereas the GT3 will go all day. I didn't experience any HP loss in my four days at the track, but like I said I'm probably not good enough to be pushing the car to its limits so as to make those symptoms manifest. There are also upgraded intercoolers available if that becomes an issue.

Not sure any of that was helpful.
Very helpful, thanks
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Old 03-16-2017, 09:46 AM
  #58  
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That black turbo is beautiful!
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Old 03-17-2017, 01:25 PM
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Old 03-24-2017, 04:55 PM
  #60  
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Is there any benefit to adding Sport DSC to a stock 991.1 turbo? http://www.tpcracing.com/dsc.html

Not clear to me whether this is actually for my car or not.
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