991.2 GTS with coilover upgrade?
11-02-2017, 02:55 AM
#16
Understand the need for coil-overs in race cars.
Understood the need for coil-overs in older street cars.
Stopped understanding the "upgrade" around the time PASM showed up. Tested a very well set up 997 Turbo with GT3 arms, new ARBs, etc on stock PASM dampers with H&R springs and then the exact same car on $10,000 coil-overs set up by a big-name shop. The car was MUCH better on back roads with the PASM and H&R springs, and I was surprised to find that I preferred it that way on track, too.
So the upgrade might actually be a downgrade. Especially as PASM has only gotten better since the 997 era. My advice? Start with DSC and/or some H&R springs if you want to get the car a little lower and a little firmer. The beauty of PASM dampers is they adjust to deal with the oscillations as needed...and were set up by some of the best suspension people on earth.
EDIT: Just saw that you're in Taiwan. May I recommend calling Tom or Mike at TPC Racing in Maryland? I know it's a world away, but I've come across very few people who have a "knack" for great street cars that also do well with track work. Mike Levitas is one of them. It would be interesting to see what he says. I'm sure DSC will be part of his solution, but I'd be curious what else he would recommend. Nice call on the move from RS to GTS—should be a great car as a daily!
Understood the need for coil-overs in older street cars.
Stopped understanding the "upgrade" around the time PASM showed up. Tested a very well set up 997 Turbo with GT3 arms, new ARBs, etc on stock PASM dampers with H&R springs and then the exact same car on $10,000 coil-overs set up by a big-name shop. The car was MUCH better on back roads with the PASM and H&R springs, and I was surprised to find that I preferred it that way on track, too.
So the upgrade might actually be a downgrade. Especially as PASM has only gotten better since the 997 era. My advice? Start with DSC and/or some H&R springs if you want to get the car a little lower and a little firmer. The beauty of PASM dampers is they adjust to deal with the oscillations as needed...and were set up by some of the best suspension people on earth.
EDIT: Just saw that you're in Taiwan. May I recommend calling Tom or Mike at TPC Racing in Maryland? I know it's a world away, but I've come across very few people who have a "knack" for great street cars that also do well with track work. Mike Levitas is one of them. It would be interesting to see what he says. I'm sure DSC will be part of his solution, but I'd be curious what else he would recommend. Nice call on the move from RS to GTS—should be a great car as a daily!
11-02-2017, 03:14 AM
#17
I am currently running H&R on my gts , ride quality is almost oem, I’m looking for that flush look with aftermarket wheels, hence why I am looking into coilovers. With proper rebound/compression settings , I think coilovers can have a better ride quality than oem pasm? While improving handling and feedbacks.
I think this dude got a perfect stance with Bilsteins.
Does the sport button still work with them?
11-02-2017, 03:53 AM
#18
Before people change they should at least understand what they have as a minimum - current springs rates (kgf/mm lbs/in) relative to the replacement - how these work with the dynamic range of the current shock absorbers, how the pitch component is balanced by the roll component largely governed by the anti roll bars (thickness/ ratio front to back). Let alone how this relates to COG and roll centre or yaw control.
More often than not I have seen coil overs make a cars handling/ ride characteristics worse rather than better.
Saying that, some groups do make model specific set ups that can be good for a specific purpose.
I have used some pretty good gear by Reiger or Drummond Motor sports but these were hard core rally set ups.
If you genuinely feel the need to do it I would go with KW
https://www.kwsuspensions.net/porsche_911_991
Perhaps something like this, which is available for the S
https://www.kwsuspensions.net/produc...sport/39771243
This spring kit may be a better option for the GTS
https://www.kwsuspensions.net/produc..._kits/25371063
For reference the KW spring rates for the slightly different 25371043 adjustable springs are front - 48.7N/mm + helper 10N/mm and rear 100N/mm + helper 10N/mm (or in old units ~280lbs/in front, 570lbs/in rear - helpers 57lbs/in).
What is your current set up PASM or S-PASM? What are you trying to achieve?
Last edited by randr; 11-02-2017 at 05:17 AM.
11-02-2017, 04:00 AM
#19
Understand the need for coil-overs in race cars.
Understood the need for coil-overs in older street cars.
Stopped understanding the "upgrade" around the time PASM showed up. Tested a very well set up 997 Turbo with GT3 arms, new ARBs, etc on stock PASM dampers with H&R springs and then the exact same car on $10,000 coil-overs set up by a big-name shop. The car was MUCH better on back roads with the PASM and H&R springs, and I was surprised to find that I preferred it that way on track, too.
So the upgrade might actually be a downgrade. Especially as PASM has only gotten better since the 997 era. My advice? Start with DSC and/or some H&R springs if you want to get the car a little lower and a little firmer. The beauty of PASM dampers is they adjust to deal with the oscillations as needed...and were set up by some of the best suspension people on earth.
Understood the need for coil-overs in older street cars.
Stopped understanding the "upgrade" around the time PASM showed up. Tested a very well set up 997 Turbo with GT3 arms, new ARBs, etc on stock PASM dampers with H&R springs and then the exact same car on $10,000 coil-overs set up by a big-name shop. The car was MUCH better on back roads with the PASM and H&R springs, and I was surprised to find that I preferred it that way on track, too.
So the upgrade might actually be a downgrade. Especially as PASM has only gotten better since the 997 era. My advice? Start with DSC and/or some H&R springs if you want to get the car a little lower and a little firmer. The beauty of PASM dampers is they adjust to deal with the oscillations as needed...and were set up by some of the best suspension people on earth.
The most the aftermarket can realistically hope for vs Porsche today is to narrow the suspension's breadth to focus it on one surface, tire or aspect of performance. Doing so can yield benefits, but it comes at a cost. My friend's 997.2 GT3 RS won the PCA Parade autocross this year and competes nationally. He's swapped his PASM system for adjustable coil-overs and found time, in part because he's running much sticker tires than the factory designed for. The operating window, however, is very narrow relative to PASM, and the shocks must be re-tuned at each event for maximum performance. Get it wrong and it's slower than stock, as he unfortunately found on the first day of SCCA nationals this year when the surface was bumpier than expected.
For mixed street use on all types of roads I wouldn't even try to improve over the factory unless you're specifically trying to do something different, ie lower the car, optimize for smooth roads, etc. Even then I'd first use factory parts if possible.
Suspension has evolved into a far more complex system than most appreciate, and the consequences of getting it wrong are occasionally both severe and non-obvious. GT4 strut-tower failures are a case in point: simply lowering the car outside of the factory recommended ride-height range dramatically increases the risk of a $20k+ failure over a pot-hole. Lowering springs do the same thing, but in a way very few either appreciate or can quantify. Not something your suspension vendor is likely to dwell on when making the sale...
Last edited by Petevb; 11-02-2017 at 09:49 AM.
11-02-2017, 05:09 AM
#20
For street duty there's no question that's it's very difficult to improve on Porsche's best these days. Tuning suspension for the street is one of the trickiest automotive engineering challenges, and the level of sophistication modern manufactures bring to bear is far beyond the aftermarket- dynamic simulation, shaker rigs, kinematics & compliance machines, custom progressive rate elastomer bump stops, the ability to tune tires to match the suspension, etc.
The most the aftermarket can realistically hope for today is to narrow the suspension's breadth to focus it on one surface, tire or aspect of performance. Doing so can yield benefits, but it comes at a cost. My friend's 997.2 GT3 RS won the PCA Parade autocross this year and competes nationally. He's swapped his PASM system for adjustable coil-overs and found time, in part because he's running much sticker tires than the factory designed for. The operating window, however, is very narrow relative to PASM, and the shocks must be re-tuned at each event for maximum performance. Get it wrong and it's clearly much slower than stock, as he unfortunately found on the first day of SCCA nationals this year when the surface was bumpier than expected.
For mixed street use on all types of roads I wouldn't even try to improve over the factory unless you're specifically trying to do something different, ie lower the car, optimize for smooth roads, etc. Even then I'd first use factory parts if possible.
Suspension has evolved into a far more complex system than most appreciate, and the consequences of getting it wrong are occasionally both severe and non-obvious. GT4 strut-tower failures are a case in point: simply lowering the car outside of the factory recommended ride-height range dramatically increases the risk of a $20k+ failure over a pot-hole. Lowering springs do the same thing, but in a way very few either appreciate of can quantify. Not something your suspension vendor is likely to dwell on when making the sale...
The most the aftermarket can realistically hope for today is to narrow the suspension's breadth to focus it on one surface, tire or aspect of performance. Doing so can yield benefits, but it comes at a cost. My friend's 997.2 GT3 RS won the PCA Parade autocross this year and competes nationally. He's swapped his PASM system for adjustable coil-overs and found time, in part because he's running much sticker tires than the factory designed for. The operating window, however, is very narrow relative to PASM, and the shocks must be re-tuned at each event for maximum performance. Get it wrong and it's clearly much slower than stock, as he unfortunately found on the first day of SCCA nationals this year when the surface was bumpier than expected.
For mixed street use on all types of roads I wouldn't even try to improve over the factory unless you're specifically trying to do something different, ie lower the car, optimize for smooth roads, etc. Even then I'd first use factory parts if possible.
Suspension has evolved into a far more complex system than most appreciate, and the consequences of getting it wrong are occasionally both severe and non-obvious. GT4 strut-tower failures are a case in point: simply lowering the car outside of the factory recommended ride-height range dramatically increases the risk of a $20k+ failure over a pot-hole. Lowering springs do the same thing, but in a way very few either appreciate of can quantify. Not something your suspension vendor is likely to dwell on when making the sale...
11-02-2017, 04:20 PM
#24
11-02-2017, 09:27 PM
#25
Race Director
1st how,does the sunroof affect TPC’s DSM PASM shock tuning?
2nd on my 2012GTS (997) I did the Bilstein B16 Damptronics. I had no issues with them on street or track. However I didn’t really feel they made a night and day difference on the track. I drive Sebring mostly which has all,sorts of surfaces and the Damptronics coilovers didn’t improve my lap times nor inspire any extra confidence.
Id say the difference in feeling was that Damptronics in normal mode felt like PASM in Sport mode and Damptronics in Sport mode was slightly stiffer.
2nd on my 2012GTS (997) I did the Bilstein B16 Damptronics. I had no issues with them on street or track. However I didn’t really feel they made a night and day difference on the track. I drive Sebring mostly which has all,sorts of surfaces and the Damptronics coilovers didn’t improve my lap times nor inspire any extra confidence.
Id say the difference in feeling was that Damptronics in normal mode felt like PASM in Sport mode and Damptronics in Sport mode was slightly stiffer.
11-02-2017, 10:56 PM
#26
11-02-2017, 11:01 PM
#27
Race Director
11-03-2017, 10:34 AM
#28
I was going with DSC back in June but got this from them. There was another post recently asking any local who has sunroof that wants to help them. But none responded I believe.
There's a little piece in front of the sunroof that raises to help with aerodynamics when the sunroof is open. It must be controlled by a CAN command via the PASM controller. I only have one reported instance of this right now, so all of this is hypothesis at this point, but in that one case, the DSC controller does not raise the piece in front of the sunroof causing a suspension-related error on the dash. It doesn't seem to affect the suspension, shocks, or anything else in the car besides failing to raise that piece and tripping the error light. The error light then goes away once the sunroof is closed again.
There's a little piece in front of the sunroof that raises to help with aerodynamics when the sunroof is open. It must be controlled by a CAN command via the PASM controller. I only have one reported instance of this right now, so all of this is hypothesis at this point, but in that one case, the DSC controller does not raise the piece in front of the sunroof causing a suspension-related error on the dash. It doesn't seem to affect the suspension, shocks, or anything else in the car besides failing to raise that piece and tripping the error light. The error light then goes away once the sunroof is closed again.
11-03-2017, 02:57 PM
#29
RL Community Team
Rennlist Member
Rennlist Member
11-03-2017, 02:59 PM
#30
RL Community Team
Rennlist Member
Rennlist Member
I was going with DSC back in June but got this from them. There was another post recently asking any local who has sunroof that wants to help them. But none responded I believe.
There's a little piece in front of the sunroof that raises to help with aerodynamics when the sunroof is open. It must be controlled by a CAN command via the PASM controller. I only have one reported instance of this right now, so all of this is hypothesis at this point, but in that one case, the DSC controller does not raise the piece in front of the sunroof causing a suspension-related error on the dash. It doesn't seem to affect the suspension, shocks, or anything else in the car besides failing to raise that piece and tripping the error light. The error light then goes away once the sunroof is closed again.
There's a little piece in front of the sunroof that raises to help with aerodynamics when the sunroof is open. It must be controlled by a CAN command via the PASM controller. I only have one reported instance of this right now, so all of this is hypothesis at this point, but in that one case, the DSC controller does not raise the piece in front of the sunroof causing a suspension-related error on the dash. It doesn't seem to affect the suspension, shocks, or anything else in the car besides failing to raise that piece and tripping the error light. The error light then goes away once the sunroof is closed again.
Modern cars these days. I remember the first time I had fault codes pulled in my '04 V70R. I had 4 pages of stored codes...and absolutely everything worked fine and I had no warning lights. There are CAN modules for everything!