Clutch fault on GT2 ?
02-07-2009, 07:51 AM
#1
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Clutch fault on GT2 ?
I have 560PS/700NM exhaust kit from Cargraphic/RS Tuning and my clutch is slipping in 3rd gear upwards at around 3000-4000rpm....
OK the temperature is cold so probably more torque than quoted but surely Porsche should have built more tolerance into the standard clutch ?
GT2Driver on here has told me that his friend had a similar problem on a stock GT2, has anyone else on here had similar issues ?
I know what my dealer will say if I took it in
but would be interested if others had any problems and there may be some fault ?
To test, get in 4th gear at 3000rpm and stab hard the throttle WOT the abrubt onset of the torque is what seems to do it, there appears to be a bit of overboost as the boost ramps up which may well be spiking the torque number up way into the mid 700sNM in which case there is my reason....
OK the temperature is cold so probably more torque than quoted but surely Porsche should have built more tolerance into the standard clutch ?
GT2Driver on here has told me that his friend had a similar problem on a stock GT2, has anyone else on here had similar issues ?
I know what my dealer will say if I took it in
but would be interested if others had any problems and there may be some fault ?To test, get in 4th gear at 3000rpm and stab hard the throttle WOT the abrubt onset of the torque is what seems to do it, there appears to be a bit of overboost as the boost ramps up which may well be spiking the torque number up way into the mid 700sNM in which case there is my reason....
02-07-2009, 09:42 AM
#2
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No problems here, even while driving it really hard (track). The only thing that slips is the rear tires 
However, the clutch does smell a bit after driving in heavy traffic.
Sounds like you have a heavily used clutch...
Has anyone else driven the car? It is a heavy clutch and I can just foresee someone not use to it driving along with the left foot over it all the time (wife/girlfriend on high heels..)
However, the clutch does smell a bit after driving in heavy traffic.
Sounds like you have a heavily used clutch...
Has anyone else driven the car? It is a heavy clutch and I can just foresee someone not use to it driving along with the left foot over it all the time (wife/girlfriend on high heels..)
02-07-2009, 06:49 PM
#4
Sounds like the clutch has been "glazed" (usually from a gross rpm difference between input and output shaft as the clutch is released) by side-stepping the clutch or flaring during bad up-shifts. Any chance the shop did some "calibration" driving or a lot of dyno time? Any chance of a oil on the clutch plate or the flywheel? Did the shop crack the transaxle off the engine during any of the work? (Greasy paw prints can be more than enough to start the slipping that only becomes worse as friction temperatures skyrocket.) If the engine was developing enough torque to overpower the clutch for the given pressure plate load, I'm guessing a bent conrod would have been the alternative, so it's a useful safety valve anyway.
02-09-2009, 06:41 AM
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To the owners: thanks for the feedback....
To CarerraGT: thanks for your thoughts... The car has only been driven my me since it came off the transporter, apart from 5 miles by head Porsche tech who did not abuse it in any way. Only exhaust components and oil change have been carried out so no way to contaminate clutch bits...
I am going for the overboost/cold temp story since it doesn't slip everytime, one has to be quite deliberate to bring the overboost on at peak torque which is now somewaht higher presumably thanks to the exhaust mods letting the programming deliver its maximum values.... if you just ride the torque at WOT from lower revs it does not overboost and there is no problem....
To CarerraGT: thanks for your thoughts... The car has only been driven my me since it came off the transporter, apart from 5 miles by head Porsche tech who did not abuse it in any way. Only exhaust components and oil change have been carried out so no way to contaminate clutch bits...
I am going for the overboost/cold temp story since it doesn't slip everytime, one has to be quite deliberate to bring the overboost on at peak torque which is now somewaht higher presumably thanks to the exhaust mods letting the programming deliver its maximum values.... if you just ride the torque at WOT from lower revs it does not overboost and there is no problem....
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03-14-2009, 06:14 AM
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Hi Toby,
I had exactly the same issue yesterday, with clutch slipping from 4000 revs in 3rd gear onwards.
Never felt before, but previously I only tracked the car in cold and wet weather, therefore the poor grip was taking the lead there, with tyres slipping, not clutch.
Now with approx 14/16 degrees and a good grip, the clutch slips under full torque.
All is ok during less aggressive driving, when power builds slowly.
Everything points to the pressure plate not being able to handle the torque.
My GT2 is a RS Tuning stage 2 (which they claim to be 600hp/780NM).
Did you solve the issue in any way or form? Did you go for a pressure plate upgrade?
I noticed that Cargraphic offers a sport pressure plate claimed to handle 890NM.
Also FVD offers one, up to 1050 NM (which will be probably too strong on the pedal and disk, I reckon).
Let me have your thoughts, please.
Looking forward for a drive together at first opportunity!
All the best,
Paolo
PS: Left aside this issue, the car is a dream; I reckon you are very happy with your, too. Ciao
I had exactly the same issue yesterday, with clutch slipping from 4000 revs in 3rd gear onwards.
Never felt before, but previously I only tracked the car in cold and wet weather, therefore the poor grip was taking the lead there, with tyres slipping, not clutch.
Now with approx 14/16 degrees and a good grip, the clutch slips under full torque.
All is ok during less aggressive driving, when power builds slowly.
Everything points to the pressure plate not being able to handle the torque.
My GT2 is a RS Tuning stage 2 (which they claim to be 600hp/780NM).
Did you solve the issue in any way or form? Did you go for a pressure plate upgrade?
I noticed that Cargraphic offers a sport pressure plate claimed to handle 890NM.
Also FVD offers one, up to 1050 NM (which will be probably too strong on the pedal and disk, I reckon).
Let me have your thoughts, please.
Looking forward for a drive together at first opportunity!
All the best,
Paolo
PS: Left aside this issue, the car is a dream; I reckon you are very happy with your, too. Ciao
03-14-2009, 07:04 AM
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Hey Paolo
Great to hear from you
It seems that the cold temperatures affect torque even more than I had thought - mine is not slipping now at all ~10+degC but it was the 3degC and below combined with that aggressive use of the throttle around 2600rpm which could induce the slip...
You definately need that pressure plate, either CG, RS or I think Gert at Carnewal is a good source www.carnewal.com.
You may have seen the Maha dyno which I posted elsewhere - not sure how accurate the torque # is but feels about right for the road performance
I found out that to move onto the stage 2 600PS/787NM kit I need to swap out the 200 cell cats for 100 cell cats which I didn't realise... that and the crappy exchange rate are not motivating me to change just yet....
Great to hear from you
It seems that the cold temperatures affect torque even more than I had thought - mine is not slipping now at all ~10+degC but it was the 3degC and below combined with that aggressive use of the throttle around 2600rpm which could induce the slip...
You definately need that pressure plate, either CG, RS or I think Gert at Carnewal is a good source www.carnewal.com.
You may have seen the Maha dyno which I posted elsewhere - not sure how accurate the torque # is but feels about right for the road performance
I found out that to move onto the stage 2 600PS/787NM kit I need to swap out the 200 cell cats for 100 cell cats which I didn't realise... that and the crappy exchange rate are not motivating me to change just yet....
03-14-2009, 05:45 PM
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Thanks, Toby
We will take down the clutch for inspection, if everything in good order we will try the stronger pressure plate with standard clutch disk and see what the result will be.
Always interesting reading about your testing results: very precise, no room for guessing or gut feelings.
Facts, not words!!!
Indeed I have the 100 cells, which are ok even in urban driving
Ciao!
We will take down the clutch for inspection, if everything in good order we will try the stronger pressure plate with standard clutch disk and see what the result will be.
Always interesting reading about your testing results: very precise, no room for guessing or gut feelings.
Facts, not words!!!
Indeed I have the 100 cells, which are ok even in urban driving
Ciao!
04-05-2009, 03:06 PM
#12
Three Wheelin'
pmf, How is the Cargraphic 600 PS stage 2 package?
Food for thought, the measure of HP is done thru the conversion of torque numbers...which means that the two numbers are ALWAYS equal at 5250 rpm.
If you see a dyno which has a graph that does not show this equal number at 5250 rpm there is a problem somewhere.
I learned this from a book written by the late John Lingenfelter who was a one of the greatest tuners of Corvettes and a mechanical engineer.
He also helped GM design and engineer several racing programs.
Food for thought, the measure of HP is done thru the conversion of torque numbers...which means that the two numbers are ALWAYS equal at 5250 rpm.
If you see a dyno which has a graph that does not show this equal number at 5250 rpm there is a problem somewhere.
I learned this from a book written by the late John Lingenfelter who was a one of the greatest tuners of Corvettes and a mechanical engineer.
He also helped GM design and engineer several racing programs.
04-06-2009, 07:31 AM
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pmf, How is the Cargraphic 600 PS stage 2 package?
Food for thought, the measure of HP is done thru the conversion of torque numbers...which means that the two numbers are ALWAYS equal at 5250 rpm.
If you see a dyno which has a graph that does not show this equal number at 5250 rpm there is a problem somewhere.
I learned this from a book written by the late John Lingenfelter who was a one of the greatest tuners of Corvettes and a mechanical engineer.
He also helped GM design and engineer several racing programs.
Food for thought, the measure of HP is done thru the conversion of torque numbers...which means that the two numbers are ALWAYS equal at 5250 rpm.
If you see a dyno which has a graph that does not show this equal number at 5250 rpm there is a problem somewhere.
I learned this from a book written by the late John Lingenfelter who was a one of the greatest tuners of Corvettes and a mechanical engineer.
He also helped GM design and engineer several racing programs.
Last edited by TB993tt; 04-06-2009 at 10:17 AM.
04-06-2009, 09:01 AM
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z06,
The Cargraphic stage 2, which is by the way an RS Tuning product, is almost perfect for my kind of use.
Very powerful and responsive to the throttle, sensitive to load transfer at any pressure/lift on the pedals, anyway not too aggressive or noisy to limit daily use of the car.
The only thing that you might consider on top of it are, on my opinion, high efficiency intercoolers; this would be quite an expensive additional step, anyway, compared to the rest of the package.
The car had no problem whatsoever after the upgrade, but the clutch, which I solved installing a stronger pressure plate.
Keep in mind, anyway, that I'm used to switch off SC and TC as soon as I pass the track gates, so I can't tell you how these systems will react to increased power and torque, if they will last, etc.
Best of luck with your car, the 997GT2 is a masterpiece, IMHO.
Ciao
The Cargraphic stage 2, which is by the way an RS Tuning product, is almost perfect for my kind of use.
Very powerful and responsive to the throttle, sensitive to load transfer at any pressure/lift on the pedals, anyway not too aggressive or noisy to limit daily use of the car.
The only thing that you might consider on top of it are, on my opinion, high efficiency intercoolers; this would be quite an expensive additional step, anyway, compared to the rest of the package.
The car had no problem whatsoever after the upgrade, but the clutch, which I solved installing a stronger pressure plate.
Keep in mind, anyway, that I'm used to switch off SC and TC as soon as I pass the track gates, so I can't tell you how these systems will react to increased power and torque, if they will last, etc.
Best of luck with your car, the 997GT2 is a masterpiece, IMHO.
Ciao
04-06-2009, 10:46 AM
#15
Three Wheelin'
z06,
The Cargraphic stage 2, which is by the way an RS Tuning product, is almost perfect for my kind of use.
Very powerful and responsive to the throttle, sensitive to load transfer at any pressure/lift on the pedals, anyway not too aggressive or noisy to limit daily use of the car.
The only thing that you might consider on top of it are, on my opinion, high efficiency intercoolers; this would be quite an expensive additional step, anyway, compared to the rest of the package.
The car had no problem whatsoever after the upgrade, but the clutch, which I solved installing a stronger pressure plate.
Keep in mind, anyway, that I'm used to switch off SC and TC as soon as I pass the track gates, so I can't tell you how these systems will react to increased power and torque, if they will last, etc.
Best of luck with your car, the 997GT2 is a masterpiece, IMHO.
Ciao
The Cargraphic stage 2, which is by the way an RS Tuning product, is almost perfect for my kind of use.
Very powerful and responsive to the throttle, sensitive to load transfer at any pressure/lift on the pedals, anyway not too aggressive or noisy to limit daily use of the car.
The only thing that you might consider on top of it are, on my opinion, high efficiency intercoolers; this would be quite an expensive additional step, anyway, compared to the rest of the package.
The car had no problem whatsoever after the upgrade, but the clutch, which I solved installing a stronger pressure plate.
Keep in mind, anyway, that I'm used to switch off SC and TC as soon as I pass the track gates, so I can't tell you how these systems will react to increased power and torque, if they will last, etc.
Best of luck with your car, the 997GT2 is a masterpiece, IMHO.
Ciao
Does RS Tuning change the 6750 rpm redline? most US tuners have gone to
7k rpm.
"Very powerful and responsive to the throttle, sensitive to load transfer at any pressure/lift on the pedals, anyway not too aggressive or noisy to limit daily use of the car".
I have noticed how stable the stock GT2 is at pressure/lift of the pedals.. with the RS T conversion, does it change ... to be a concern?
Agreed..IC would be nice but that is a major expence, still trying to understand why there is such a large price difference between IC.
There are a couple made in the US and 9ff has one as well and then you look at Manthey and RS T and they are triple the cost?
Pressure plate on my list.
" the 997GT2 is a masterpiece, IMHO."
Amazing car!
Thank you,