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.1 and .2 GT3 stock spring rates?

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Old 12-05-2017 | 12:49 AM
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Default .1 and .2 GT3 stock spring rates?

Does anyone know or have info about the actual stock spring rates for either the .1 or .2 GT3/RS ? I can't find it anywhere.

The eagle has landed and the work begins.....
Old 12-06-2017 | 12:07 AM
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Yes The spring rates for the 991-I GT3 and 991-II GT3 are as follows...
991-I GT3

Front: 45 N/mm (257 lb/in)

Rear: 120 N/mm (685 lb/in)

991-II GT3

Front: 45 N/mm (257 lb/in)

Rear: 120 N/mm (685 lb/in)
Old 12-06-2017 | 09:59 AM
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Thanks, those looks almost identical to 997.2 GT3 spring rates.

I confirmed with Bilstein that their Clubsport kit will be identical for the .2 GT3, with rates of 90 N/mm (456 lb/in) and 160 N/mm (913 lb/in).

Last edited by Mvez; 12-06-2017 at 10:18 AM.
Old 12-06-2017 | 01:48 PM
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Originally Posted by SmokinGTS
Yes The spring rates for the 991-I GT3 and 991-II GT3 are as follows...
991-I GT3

Front: 45 N/mm (257 lb/in)

Rear: 120 N/mm (685 lb/in)

991-II GT3

Front: 45 N/mm (257 lb/in)

Rear: 120 N/mm (685 lb/in)
Thank you. Very interesting. Some early .2 owners felt like the .2 was firmer than the .1.
This could be differences in Tire Side wall stiffness between the MPSC2 N0 vs the MPSC2 N1's or differences in Shock Absorbers.

Does anyone know if the same Shock Absorbers are used on the .1 vs the .2?

BTW, A "modified" GT3RS with unstated HP (very unusual) driven by Christian Gebhardt has recently set a new Hockenheim Short Track Lap Record @ 1:05.8,
faster than the Porsche 918 Spyder time of 1:06.30 with 887 HP. Same Driver drove the MB AMG GT-R with 585 HP in 1:06.4 and ZO6 C7 Corvette, 659 HP in 1:06.9,
Ferrari 488 GTB in 1:07.0, Lamborghini Hurracan 610-4, 609 HP in 1:07.50, Porsche 911 GT3-2, 500 HP in 1:07.9, Porsche GTS, 450 HP and presumably on "Street tires" in 1:08.00.

Porsche TTS-2 Time is 1:07.5, TTS-1 is 1:08.2, 991-1 GT3RS-1 is 1:08.5 with GT3-1 Time of 1:09.2

I suspect the "Modified GT3RS", the new Lap Record Holder of Hockenheim, is actually the new GT3RS-2. WOW!!!!! And the new GTS with "only" 450 HP is likely as fast as the GT3 WOW-WOW
Old 12-06-2017 | 01:52 PM
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Wasn't that the "Manthey" GT3 RS?

That is not the 991.2 GT3 RS.
Old 12-06-2017 | 02:16 PM
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Originally Posted by FastLaneTurbo
Thank you. Very interesting. Some early .2 owners felt like the .2 was firmer than the .1.
This could be differences in Tire Side wall stiffness between the MPSC2 N0 vs the MPSC2 N1's or differences in Shock Absorbers.

Does anyone know if the same Shock Absorbers are used on the .1 vs the .2?

BTW, A "modified" GT3RS with unstated HP (very unusual) driven by Christian Gebhardt has recently set a new Hockenheim Short Track Lap Record @ 1:05.8,
faster than the Porsche 918 Spyder time of 1:06.30 with 887 HP. Same Driver drove the MB AMG GT-R with 585 HP in 1:06.4 and ZO6 C7 Corvette, 659 HP in 1:06.9,
Ferrari 488 GTB in 1:07.0, Lamborghini Hurracan 610-4, 609 HP in 1:07.50, Porsche 911 GT3-2, 500 HP in 1:07.9, Porsche GTS, 450 HP and presumably on "Street tires" in 1:08.00.

Porsche TTS-2 Time is 1:07.5, TTS-1 is 1:08.2, 991-1 GT3RS-1 is 1:08.5 with GT3-1 Time of 1:09.2

I suspect the "Modified GT3RS", the new Lap Record Holder of Hockenheim, is actually the new GT3RS-2. WOW!!!!! And the new GTS with "only" 450 HP is likely as fast as the GT3 WOW-WOW
The shocks are the same for the .1 and .2, but the internal valving and electronic control have been re-worked a bit, per Porsche.

The modified 3RS is the Manthey car, which has a set of KW racing shocks from the GT3R on it, which is where most of the lap time is coming from. Stiffer spring rates and manually adjustable shocks are really what help this car shine on track. Exactly why I'm adding a set of Bilstein Clubsports to mine.
Old 12-06-2017 | 03:33 PM
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Did anyone notice that their .2 sat higher at the front lip than the .1? My .2 was 1/2†higher. Wasn’t sure if I need to drive the car (only10 miles) to get springs to settle(?) or should I just go ahead and lower the 1/2â€-1†that I can with stock suspension? Appreciate your feedback.
Old 12-07-2017 | 12:33 AM
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The RS has the same spring rates, I just want my car to handle like a RS. So whats the difference? The Box?
Old 12-07-2017 | 12:39 PM
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Originally Posted by Mvez
The shocks are the same for the .1 and .2, but the internal valving and electronic control have been re-worked a bit, per Porsche.

The modified 3RS is the Manthey car, which has a set of KW racing shocks from the GT3R on it, which is where most of the lap time is coming from. Stiffer spring rates and manually adjustable shocks are really what help this car shine on track. Exactly why I'm adding a set of Bilstein Clubsports to mine.
In 1995 I had the privelege of working with Hans Stuck at Sebring on our newly delivered 993 GT2 Race Cars. Our cars had 4 sets of Springs, each with different Spring Rates. Each set had a 4 position rotating collar which locked the adjacent coils further adjusting Spring Rates. His lap times kept improving with each increase of
Spring Rates until we had maxed out both Front and Rear Spring until we had reached the absolute stiffest spring rates available. My recollection is they were
about 1,750 Lbs / corner, practically "Locked and Welded" which I used during the next 10 years of successfully racing that car.
Re the Manthey GT3RS, considering the incredible Laptimes, I would expect Porsche has been carefully observing those results and I would be surprised
if they did not incorporate many of those modifications in both the new GT2RS and GT3RS.
Old 12-08-2017 | 09:19 AM
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Since we are talking setup, what's a good baseline alignment, ride height for the new car (or the 991.1) for track use?
Thanks
Old 03-05-2018 | 09:10 PM
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Does anyone know the spring rates for the KW Clubsport kit for the 991 GT3 (part # 39771255)?
Old 03-05-2018 | 10:16 PM
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If the 991.1 and 991.2 GT3 both have the same shocks and springs, then why is the ride of the new .2 GT3 softer and more compliant on public roads?
Old 03-06-2018 | 05:35 AM
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Slightly modified dampers and softer PASM setup.

I would like to have stiffer springs in my .1.
Old 04-11-2018 | 05:55 PM
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Originally Posted by SmokinGTS
Yes The spring rates for the 991-I GT3 and 991-II GT3 are as follows...
991-I GT3

Front: 45 N/mm (257 lb/in)

Rear: 120 N/mm (685 lb/in)

991-II GT3

Front: 45 N/mm (257 lb/in)

Rear: 120 N/mm (685 lb/in)
where does these data come from?

I just measured rear 991.1 GT3 spring and it’s 560lb/in

Also 991.1 GT3 springs have different part numbers compare to 991.2

also spring shape on 991.1 is different vs 991.2 . Coils are a lot thicker on 991 and spacing is different. 991.2 looks more like a progressive spring.
Old 07-29-2019 | 02:01 PM
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Originally Posted by doba_s



where does these data come from?

I just measured rear 991.1 GT3 spring and it’s 560lb/in

Also 991.1 GT3 springs have different part numbers compare to 991.2

also spring shape on 991.1 is different vs 991.2 . Coils are a lot thicker on 991 and spacing is different. 991.2 looks more like a progressive spring.
Just wondering if anyone has resolved this yet? (I assume the spring is removed from the car, otherwise it's a motion ratio thing. Also, was it measured throughout the travel to see whether it's slightly progressive?)


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