On track experiences and video's 991 GT3 only.
08-31-2014, 02:39 PM
#301
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Anyone having knocking sounds from the front suspension? After my 3rd trackday I had some knocking so my shop looked everything over, found everything to look ok, but they gave everything a slight tighten. Knock disappeared. Then I did trackday #4, everything was fine (even for the 250km round trip to/from the track) but the next day (yesterday) the knock returned on my way to the detailer. Just sounds like something is loose, very noticeable knocking around when on uneven road surfaces, entering driveways, etc. Something seems to be loosening after hard use. Will have it checked out again this week.
08-31-2014, 02:39 PM
#302
Did my 4th trackday on Friday. The car continues to impress. I think the rear tires still have 3 days left, and very even wear (which is surprising because I’ve been intentionally sliding the car and pushing it hard). Front Left is toast, 1 more day on FR. Understeer became progressively worse each session Friday as the FL tire eroded. This was a tight course though, only had understeer issues in a few tight ones. The car is absolutely brilliant in fast sweepers and also making directional adjustments at high speed. I think that’s where RWS is really shining. The GT3 lap times (with just an alignment) were on par with well-driven and set-up Scud & C6 Z07 (both on Hoosier R6). Pad/Rotor life looking good. Getting ABS under hard braking (even with all systems OFF) and pedal feel could be firmer. I will do lines & fluid soon (hopefully this week) and I’ll definitely go with a more aggressive pad once the stocks are closer to done.
I finally tried Auto mode on track. For me, the only benefit was not having to watch the Tach to nail a 9k upshift on straightaways but it reduced the fun/control factor significantly and I didn’t always like where it downshifted. After 3 laps I went back to manual and I doubt I’ll repeat that experiment.
Has anyone tried a 265/35 Cup2 up front? If it fits, this may help fight understeer in the tight stuff.
Anyone having knocking sounds from the front suspension? After my 3rd trackday I had some knocking so my shop looked everything over, found everything to look ok, but they gave everything a slight tighten. Knock disappeared. Then I did trackday #4, everything was fine (even for the 250km round trip to/from the track) but the next day (yesterday) the knock returned on my way to the detailer. Just sounds like something is loose, very noticeable knocking around when on uneven road surfaces, entering driveways, etc. Something seems to be loosening after hard use. Will have it checked out again this week.
I’m doing Saturday & Sunday @ Mosport GP Track (CTMP) next weekend, a much faster track than what I’ve been hitting on my 1st 4 outings so REALLY looking forward to it.
Here is an exhaust clip from Friday (old GoPro Hero1, no external mic). Just got a new GoPro 3+ Black Edition that will be running next weekend.
I finally tried Auto mode on track. For me, the only benefit was not having to watch the Tach to nail a 9k upshift on straightaways but it reduced the fun/control factor significantly and I didn’t always like where it downshifted. After 3 laps I went back to manual and I doubt I’ll repeat that experiment.
Has anyone tried a 265/35 Cup2 up front? If it fits, this may help fight understeer in the tight stuff.
Anyone having knocking sounds from the front suspension? After my 3rd trackday I had some knocking so my shop looked everything over, found everything to look ok, but they gave everything a slight tighten. Knock disappeared. Then I did trackday #4, everything was fine (even for the 250km round trip to/from the track) but the next day (yesterday) the knock returned on my way to the detailer. Just sounds like something is loose, very noticeable knocking around when on uneven road surfaces, entering driveways, etc. Something seems to be loosening after hard use. Will have it checked out again this week.
I’m doing Saturday & Sunday @ Mosport GP Track (CTMP) next weekend, a much faster track than what I’ve been hitting on my 1st 4 outings so REALLY looking forward to it.
Here is an exhaust clip from Friday (old GoPro Hero1, no external mic). Just got a new GoPro 3+ Black Edition that will be running next weekend.
08-31-2014, 03:33 PM
#303
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Very nice video. Your experience with understeer in slower tight corners and front tire wear echoes mine. Spartan put 265s on (19 Hoosiers) and had no issues on track, see hi recent post. No knocking in my car yet. If you put 265 PSC2 on the front, please share your findings. Thanks.
08-31-2014, 03:42 PM
#304
08-31-2014, 03:50 PM
#305
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I'd be interested to try a wider front tire or maybe a slick.
08-31-2014, 04:44 PM
#306
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I did Thunderhill 5 mile track again yesterday. It was ultimate heat test for the car, I think - 102F on the dash at one point, and the pavement was too hard to touch with a a bare hand. I ran two sessions with AC on and managed 3:32 in traffic. On the last session I was going for 2+ seconds better time (so 3.29 or better) but plowed wide in one corner and dropped two wheels 
. I do not know what a good time for this track is - the group, Trackmasters, was relatively mellow, with the fastest cars running 3:35-3:40.
Anyway, the car stands up to heat without issues. Simply amazing. Only tires were getting greasy, especially rears.
I noticed one interesting trait of the car - it does not want to turn on braking or even coasting as well as when on throttle. Maybe it's the diff set up or something like that, but take the same turn - coasting or decelerating, I can make it at 50MPH before car starts to plow, accelerating - 55MPH or even more, and the car will be more neutral. It just turns much better on throttle - not necessarily power-oversteer, but just moderate throttle kills understeer. It was an interesting challenge in sweepers - giving just enough throttle to prevent understeer but not too much to go too fast before the exit. In general, the car is very stable on braking, probably too stable, but has no problem rotating under power.
. I do not know what a good time for this track is - the group, Trackmasters, was relatively mellow, with the fastest cars running 3:35-3:40. Anyway, the car stands up to heat without issues. Simply amazing. Only tires were getting greasy, especially rears.
I noticed one interesting trait of the car - it does not want to turn on braking or even coasting as well as when on throttle. Maybe it's the diff set up or something like that, but take the same turn - coasting or decelerating, I can make it at 50MPH before car starts to plow, accelerating - 55MPH or even more, and the car will be more neutral. It just turns much better on throttle - not necessarily power-oversteer, but just moderate throttle kills understeer. It was an interesting challenge in sweepers - giving just enough throttle to prevent understeer but not too much to go too fast before the exit. In general, the car is very stable on braking, probably too stable, but has no problem rotating under power.
08-31-2014, 04:59 PM
#308
I did Thunderhill 5 mile track again yesterday. It was ultimate heat test for the car, I think - 102F on the dash at one point, and the pavement was too hard to touch with a a bare hand. I ran two sessions with AC on and managed 3:32 in traffic. On the last session I was going for 2+ seconds better time (so 3.29 or better) but plowed wide in one corner and dropped two wheels . I do not know what a good time for this track is - the group, Trackmasters, was relatively mellow, with the fastest cars running 3:35-3:40.
Anyway, the car stands up to heat without issues. Simply amazing. Only tires were getting greasy, especially rears.
I noticed one interesting trait of the car - it does not want to turn on braking or even coasting as well as when on throttle. Maybe it's the diff set up or something like that, but take the same turn - coasting or decelerating, I can make it at 50MPH before car starts to plow, accelerating - 55MPH or even more, and the car will be more neutral. It just turns much better on throttle - not necessarily power-oversteer, but just moderate throttle kills understeer. It was an interesting challenge in sweepers - giving just enough throttle to prevent understeer but not too much to go too fast before the exit. In general, the car is very stable on braking, probably too stable, but has no problem rotating under power.
. I do not know what a good time for this track is - the group, Trackmasters, was relatively mellow, with the fastest cars running 3:35-3:40. Anyway, the car stands up to heat without issues. Simply amazing. Only tires were getting greasy, especially rears.
I noticed one interesting trait of the car - it does not want to turn on braking or even coasting as well as when on throttle. Maybe it's the diff set up or something like that, but take the same turn - coasting or decelerating, I can make it at 50MPH before car starts to plow, accelerating - 55MPH or even more, and the car will be more neutral. It just turns much better on throttle - not necessarily power-oversteer, but just moderate throttle kills understeer. It was an interesting challenge in sweepers - giving just enough throttle to prevent understeer but not too much to go too fast before the exit. In general, the car is very stable on braking, probably too stable, but has no problem rotating under power.
As for the throttle vs understeer, that's the nature of the 911 -- there's just never going to be enough weight on the front with a neutral or balanced throttle for any given steering angle if the objective is to rotate the car, so you have to get the weight fully on the nose under brakes to turn in, then transferred to the rear under power once the car rotates enough to peg the apex. You might also be running just a hair too much negative camber up front just eyeballing the car the other week at Laguna -- the maximum 2.7-2.8 might be more than the Sport Cup 2's want (might be ideal or even not enough for the Hoosiers) but heavier straight line braking to get weight on the fronts, then turn in at higher speeds ... at least that's the way I was taught at the Porsche school (PSDS) which also means better brake cooling at higher road speed, less "ask" of the fronts to both slow and turn the car at the same time, greater distance for the traction of the fronts to achieve the rotation, more momentum in the rear to carry the rotation and feed in power to "feel" out the rear traction and throttle steer the nose till it kisses the apex with (in the hands of the pro's) inch-by-inch precision.
Or so the story goes. : )
Did you get tire temps? I'm guessing even if you were managing the fronts down to say 32psi (I was finding 32 "good" from my notes taken hot in the pi
uts, but 32-36 is the optimal range, though I found 36, reading off the TPMS, was a "little vague" in the fronts and "greasy?" in the rears) the tire temps may still be screaming for mercy up around 220 deg F at the very upper or even beyond the upper limits of the Sport Cups window.
08-31-2014, 09:20 PM
#309
Rennlist Member
That is one of the peculiar joys of driving street cars on the track: a/c for 100 degree days ... : )
As for the throttle vs understeer, that's the nature of the 911 -- there's just never going to be enough weight on the front with a neutral or balanced throttle for any given steering angle if the objective is to rotate the car, so you have to get the weight fully on the nose under brakes to turn in, then transferred to the rear under power once the car rotates enough to peg the apex. You might also be running just a hair too much negative camber up front just eyeballing the car the other week at Laguna -- the maximum 2.7-2.8 might be more than the Sport Cup 2's want (might be ideal or even not enough for the Hoosiers) but heavier straight line braking to get weight on the fronts, then turn in at higher speeds ... at least that's the way I was taught at the Porsche school (PSDS) which also means better brake cooling at higher road speed, less "ask" of the fronts to both slow and turn the car at the same time, greater distance for the traction of the fronts to achieve the rotation, more momentum in the rear to carry the rotation and feed in power to "feel" out the rear traction and throttle steer the nose till it kisses the apex with (in the hands of the pro's) inch-by-inch precision.
Or so the story goes. : )
Did you get tire temps? I'm guessing even if you were managing the fronts down to say 32psi (I was finding 32 "good" from my notes taken hot in the pi
uts, but 32-36 is the optimal range, though I found 36, reading off the TPMS, was a "little vague" in the fronts and "greasy?" in the rears) the tire temps may still be screaming for mercy up around 220 deg F at the very upper or even beyond the upper limits of the Sport Cups window.
As for the throttle vs understeer, that's the nature of the 911 -- there's just never going to be enough weight on the front with a neutral or balanced throttle for any given steering angle if the objective is to rotate the car, so you have to get the weight fully on the nose under brakes to turn in, then transferred to the rear under power once the car rotates enough to peg the apex. You might also be running just a hair too much negative camber up front just eyeballing the car the other week at Laguna -- the maximum 2.7-2.8 might be more than the Sport Cup 2's want (might be ideal or even not enough for the Hoosiers) but heavier straight line braking to get weight on the fronts, then turn in at higher speeds ... at least that's the way I was taught at the Porsche school (PSDS) which also means better brake cooling at higher road speed, less "ask" of the fronts to both slow and turn the car at the same time, greater distance for the traction of the fronts to achieve the rotation, more momentum in the rear to carry the rotation and feed in power to "feel" out the rear traction and throttle steer the nose till it kisses the apex with (in the hands of the pro's) inch-by-inch precision.
Or so the story goes. : )
Did you get tire temps? I'm guessing even if you were managing the fronts down to say 32psi (I was finding 32 "good" from my notes taken hot in the pi
uts, but 32-36 is the optimal range, though I found 36, reading off the TPMS, was a "little vague" in the fronts and "greasy?" in the rears) the tire temps may still be screaming for mercy up around 220 deg F at the very upper or even beyond the upper limits of the Sport Cups window.
I concur with you on temp findings. 36 is too high form the front as they start washing out a little (I have -2.15F camber).
09-03-2014, 04:07 PM
#310
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What would be a good time for Sonoma Raceway for 991 GT3? Please recommend any good vids to watch before going there. I've only driven it once in GT3, but in the rain and over 6 months ago, so could use some refresher.
09-03-2014, 04:16 PM
#311
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Thread Starter
Normal configuration I think roughly 1.48-1.50.
Nascar configuration 1.28 - 1.30.
Based on guestimating 3-5 seconds onder my yestertech RSA laptimes a couple of months ago.
Could be less difference if you cook the street tires again.
Throttle early and keep it going down ;-)
Much more treacherous than THill and Laguna Seca IMHO.
Quite the track to learn in the wet!
Nascar configuration 1.28 - 1.30.
Based on guestimating 3-5 seconds onder my yestertech RSA laptimes a couple of months ago.
Could be less difference if you cook the street tires again.
Throttle early and keep it going down ;-)
Much more treacherous than THill and Laguna Seca IMHO.
Quite the track to learn in the wet!
09-04-2014, 03:55 PM
#312
Can probably run :45's if I can get my car to stop understeering. We'll see.
Z06 with Sport cups. 4th day at Sonoma. I assume a new GT3 with Sport cup 2's should be close or faster theoretically.
Enjoy the shame of my understeer into T2.
