997TT suspension PT#1
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I've been trading notes with Fabryce at GMG and have pretty much decided to order a set of mods to reduce roll and bobbing. After 3 track days I'm convinced the TT needs these few easy changes to bring out the best along with a 4 wheel alignment.
I've settled on the following from GMG: WC Sport Springs, WC Sport Sway bar set, GT Dog bone kit, GT toe steer kit, GT thrust arm bushing kit. I'm heading to Calabogie in late-June then 4 days at WGI this summer then back to VIR in the fall so should have ample opportunity to compare and contrast versus stock.
Fact is, this car should be better on the track out of the box than it is. Hate to say it but I'm convinced that's the case. I suspect post-GMG mods the car will be pretty killer.
I've settled on the following from GMG: WC Sport Springs, WC Sport Sway bar set, GT Dog bone kit, GT toe steer kit, GT thrust arm bushing kit. I'm heading to Calabogie in late-June then 4 days at WGI this summer then back to VIR in the fall so should have ample opportunity to compare and contrast versus stock.
Fact is, this car should be better on the track out of the box than it is. Hate to say it but I'm convinced that's the case. I suspect post-GMG mods the car will be pretty killer.
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From: Palos Verdes
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So more and more of us are doing what I now consider the most important mod to the Turbo, tightening up the suspension. My car is into GMG next week for exact the same things as yours, but I will be doing it in stages so I could tell what happens when changes are made.
Bobk has a picture of the Cup car's front lower control arm above. I think if you would like to adjust front wheel camber with a lowered car, you need this (anyone corrects me if I am wrong)? Did you talk to Fabryce about this and do you plan to change this? I forgot but will later on.
I recently drive a GT class Porsche and trade-off for daily drive ability notwithstanding, sad to say, the test drive made my beloved Turbo feels so soft, so sloppy. I knew I was in "trouble" with the very first corner I took in the test car. For my taste, the 997TT simply has too much pitch/roll, too much vertical and lateral motion.
Bobk has a picture of the Cup car's front lower control arm above. I think if you would like to adjust front wheel camber with a lowered car, you need this (anyone corrects me if I am wrong)? Did you talk to Fabryce about this and do you plan to change this? I forgot but will later on.
I recently drive a GT class Porsche and trade-off for daily drive ability notwithstanding, sad to say, the test drive made my beloved Turbo feels so soft, so sloppy. I knew I was in "trouble" with the very first corner I took in the test car. For my taste, the 997TT simply has too much pitch/roll, too much vertical and lateral motion.
I've been trading notes with Fabryce at GMG and have pretty much decided to order a set of mods to reduce roll and bobbing. After 3 track days I'm convinced the TT needs these few easy changes to bring out the best along with a 4 wheel alignment.
I've settled on the following from GMG: WC Sport Springs, WC Sport Sway bar set, GT Dog bone kit, GT toe steer kit, GT thrust arm bushing kit. I'm heading to Calabogie in late-June then 4 days at WGI this summer then back to VIR in the fall so should have ample opportunity to compare and contrast versus stock.
Fact is, this car should be better on the track out of the box than it is. Hate to say it but I'm convinced that's the case. I suspect post-GMG mods the car will be pretty killer.
I've settled on the following from GMG: WC Sport Springs, WC Sport Sway bar set, GT Dog bone kit, GT toe steer kit, GT thrust arm bushing kit. I'm heading to Calabogie in late-June then 4 days at WGI this summer then back to VIR in the fall so should have ample opportunity to compare and contrast versus stock.
Fact is, this car should be better on the track out of the box than it is. Hate to say it but I'm convinced that's the case. I suspect post-GMG mods the car will be pretty killer.
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Joined: Jul 2007
Posts: 547
From: NYC
Rep Power: 42
So more and more of us are doing what I now consider the most important mod to the Turbo, tightening up the suspension. My car is into GMG next week for exact the same things as yours, but I will be doing it in stages so I could tell what happens when changes are made.
Bobk has a picture of the Cup car's front lower control arm above. I think if you would like to adjust front wheel camber with a lowered car, you need this (anyone corrects me if I am wrong)? Did you talk to Fabryce about this and do you plan to change this? I forgot but will later on.
I recently drive a GT class Porsche and trade-off for daily drive ability notwithstanding, sad to say, the test drive made my beloved Turbo feels so soft, so sloppy. I knew I was in "trouble" with the very first corner I took in the test car. For my taste, the 997TT simply has too much pitch/roll, too much vertical and lateral motion.
Bobk has a picture of the Cup car's front lower control arm above. I think if you would like to adjust front wheel camber with a lowered car, you need this (anyone corrects me if I am wrong)? Did you talk to Fabryce about this and do you plan to change this? I forgot but will later on.
I recently drive a GT class Porsche and trade-off for daily drive ability notwithstanding, sad to say, the test drive made my beloved Turbo feels so soft, so sloppy. I knew I was in "trouble" with the very first corner I took in the test car. For my taste, the 997TT simply has too much pitch/roll, too much vertical and lateral motion.
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Reason I brought it up was I think the Turbo's front camber needs to be more negative to reduce the car's tendency to understeer. eclou for example changes his front camber from the stock value of -.4 to a more GT3 like value of -1.3 or so.
If we use PSS10, front camber could be adjusted to more negative value. If we use lowering spring, however, I vaguely recall (not sure at all, I am learning and reading myself) reading that something like the lower control arm is needed to adjust for more negative camber. Please post what you find.
If we use PSS10, front camber could be adjusted to more negative value. If we use lowering spring, however, I vaguely recall (not sure at all, I am learning and reading myself) reading that something like the lower control arm is needed to adjust for more negative camber. Please post what you find.
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Agreed on the camber adjustment. The motorsport part is not totally necessary , but gives more adjustment. The axis of the shims also makes the camber adjustment very efficient geometrically ( longer or shorter control arm).
In doing the research for this project, we noted that the RS suspension has what appear to be the same rubber bushings at control arm and thrust locations ( maybe different durometer?). The only joint on the Rs that appears different is the rear subframe mounts, which are ridgid. Based upon that info, and the responses of others on the board, We concluded that just lowering the roll center and stiffening the spring rate ( basic changes on the RS), would likely add much improvemment.
But I have that billet aluminum syndrome anyway
In doing the research for this project, we noted that the RS suspension has what appear to be the same rubber bushings at control arm and thrust locations ( maybe different durometer?). The only joint on the Rs that appears different is the rear subframe mounts, which are ridgid. Based upon that info, and the responses of others on the board, We concluded that just lowering the roll center and stiffening the spring rate ( basic changes on the RS), would likely add much improvemment.
But I have that billet aluminum syndrome anyway
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eclou & brownan,
Thanks.
Bob,
Considering what your "other" car is, I feel comfortable following the general direction you are taking with the Turbo.
Thanks for sharing the pictures. I've been sitting here looking and trying to identify all the parts. LOL. So far I could I see Motorsport lower control arm, dog bones, thrust arm bushing.
Are the toe control arms in there some where? I don't seem to see them.
What is the cylindrical bushing that you are holding in your hand? Part of the motorsport lower control arm?
Are you replacing the A Arm Monoball as well?
Thanks.
Bob,
Considering what your "other" car is, I feel comfortable following the general direction you are taking with the Turbo.
Thanks for sharing the pictures. I've been sitting here looking and trying to identify all the parts. LOL. So far I could I see Motorsport lower control arm, dog bones, thrust arm bushing.
Are the toe control arms in there some where? I don't seem to see them.
What is the cylindrical bushing that you are holding in your hand? Part of the motorsport lower control arm?
Are you replacing the A Arm Monoball as well?
Agreed on the camber adjustment. The motorsport part is not totally necessary , but gives more adjustment. The axis of the shims also makes the camber adjustment very efficient geometrically ( longer or shorter control arm).
In doing the research for this project, we noted that the RS suspension has what appear to be the same rubber bushings at control arm and thrust locations ( maybe different durometer?). The only joint on the Rs that appears different is the rear subframe mounts, which are ridgid. Based upon that info, and the responses of others on the board, We concluded that just lowering the roll center and stiffening the spring rate ( basic changes on the RS), would likely add much improvemment.
But I have that billet aluminum syndrome anyway
In doing the research for this project, we noted that the RS suspension has what appear to be the same rubber bushings at control arm and thrust locations ( maybe different durometer?). The only joint on the Rs that appears different is the rear subframe mounts, which are ridgid. Based upon that info, and the responses of others on the board, We concluded that just lowering the roll center and stiffening the spring rate ( basic changes on the RS), would likely add much improvemment.
But I have that billet aluminum syndrome anyway
Last edited by cannga; May 23, 2008 at 03:47 PM.
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997tt spring rates
The cylindrical part is a custom made part to be adapted to the motorsport lower control arms. It has a spherical type bearing ( i.e. no rubber) that mounts to the car subframe. The motorsport part would come with this, but in cast configuration. You would then have to press in the monoball bearing.
Spring Rates, ( courtesy of our superior car Builder/ Bill Pfister @ Eurotech)
Stock 997TT: Front:210#/in.
Rear: 450#/in.
Biltein damptronics as received:
Front: 340#/in
Rear: 675#/in
Obviously why the dramatic improvement!!!!!!!!!!!
Bill said this was the stiffest pss9 /damptronics set he has seen(50%ftont / 60%rear stifer) . He stated that typical is in the 30-40% range. Just another variable!!!!!!
Spring Rates, ( courtesy of our superior car Builder/ Bill Pfister @ Eurotech)
Stock 997TT: Front:210#/in.
Rear: 450#/in.
Biltein damptronics as received:
Front: 340#/in
Rear: 675#/in
Obviously why the dramatic improvement!!!!!!!!!!!
Bill said this was the stiffest pss9 /damptronics set he has seen(50%ftont / 60%rear stifer) . He stated that typical is in the 30-40% range. Just another variable!!!!!!
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I've been trading notes with Fabryce at GMG and have pretty much decided to order a set of mods to reduce roll and bobbing. After 3 track days I'm convinced the TT needs these few easy changes to bring out the best along with a 4 wheel alignment.
I've settled on the following from GMG: WC Sport Springs, WC Sport Sway bar set, GT Dog bone kit, GT toe steer kit, GT thrust arm bushing kit. I'm heading to Calabogie in late-June then 4 days at WGI this summer then back to VIR in the fall so should have ample opportunity to compare and contrast versus stock.
Fact is, this car should be better on the track out of the box than it is. Hate to say it but I'm convinced that's the case. I suspect post-GMG mods the car will be pretty killer.
I've settled on the following from GMG: WC Sport Springs, WC Sport Sway bar set, GT Dog bone kit, GT toe steer kit, GT thrust arm bushing kit. I'm heading to Calabogie in late-June then 4 days at WGI this summer then back to VIR in the fall so should have ample opportunity to compare and contrast versus stock.
Fact is, this car should be better on the track out of the box than it is. Hate to say it but I'm convinced that's the case. I suspect post-GMG mods the car will be pretty killer.
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Joined: Dec 2006
Posts: 3,116
From: Palos Verdes
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Hi Bob,
Just to compare notes here. I got numbers for Bilstein that are different from yours.
Bilstein PSS10 (per phone conversation w/ Bilstein)
Front 285 Main, 115 Tender
Rear 570 Main, 145 Tender
Effective 285/570 as tenders are fully compressed.
Some more info, FWIW:
GMG Lowering Springs are stiffer than Bilstein PSS10. By how much, I don't know.
Stock 996 TT:
Front: 187
Rear: 340
997 TT springs much stiffer, I guess?
Stock 996 GT3:
Front: 225 Linear
Rear: 550 Progressive
Just to compare notes here. I got numbers for Bilstein that are different from yours.
Bilstein PSS10 (per phone conversation w/ Bilstein)
Front 285 Main, 115 Tender
Rear 570 Main, 145 Tender
Effective 285/570 as tenders are fully compressed.
Some more info, FWIW:
GMG Lowering Springs are stiffer than Bilstein PSS10. By how much, I don't know.
Stock 996 TT:
Front: 187
Rear: 340
997 TT springs much stiffer, I guess?
Stock 996 GT3:
Front: 225 Linear
Rear: 550 Progressive
The cylindrical part is a custom made part to be adapted to the motorsport lower control arms. It has a spherical type bearing ( i.e. no rubber) that mounts to the car subframe. The motorsport part would come with this, but in cast configuration. You would then have to press in the monoball bearing.
Spring Rates, ( courtesy of our superior car Builder/ Bill Pfister @ Eurotech)
Stock 997TT: Front:210#/in.
Rear: 450#/in.
Biltein damptronics as received:
Front: 340#/in
Rear: 675#/in
Obviously why the dramatic improvement!!!!!!!!!!!
Bill said this was the stiffest pss9 /damptronics set he has seen(50%ftont / 60%rear stifer) . He stated that typical is in the 30-40% range. Just another variable!!!!!!
Spring Rates, ( courtesy of our superior car Builder/ Bill Pfister @ Eurotech)
Stock 997TT: Front:210#/in.
Rear: 450#/in.
Biltein damptronics as received:
Front: 340#/in
Rear: 675#/in
Obviously why the dramatic improvement!!!!!!!!!!!
Bill said this was the stiffest pss9 /damptronics set he has seen(50%ftont / 60%rear stifer) . He stated that typical is in the 30-40% range. Just another variable!!!!!!
Last edited by cannga; May 24, 2008 at 05:40 PM.