5th and 6th gear slip when boost hits
10-28-2009, 08:46 PM
#16
Race Director
A little update:
I can't get the clutch to slip now. Today was a much warmer day. 72 degrees vs. 50 when it was slipping. Took it to my indy and we couldn't reproduce the 5th, 6th gear issue that I had the other day.
medtech is right. It is in fact still on the factory clutch with 70,000 miles on it. Never replaced. When I first got the car, I couldn't get it to slip if I tried when it was stock. Kevin's ECU flash combined with a little cold weather may have been too much for the old stock clutch to handle. We also found a transmission mount needed to be replaced. Fixing it tomorrow and will update.
I can't get the clutch to slip now. Today was a much warmer day. 72 degrees vs. 50 when it was slipping. Took it to my indy and we couldn't reproduce the 5th, 6th gear issue that I had the other day.
medtech is right. It is in fact still on the factory clutch with 70,000 miles on it. Never replaced. When I first got the car, I couldn't get it to slip if I tried when it was stock. Kevin's ECU flash combined with a little cold weather may have been too much for the old stock clutch to handle. We also found a transmission mount needed to be replaced. Fixing it tomorrow and will update.
If transmission mount bad it is possible the transmission (and engine since they're essentially one unit in the car) was twisting a possibly hindering the proper full release of the clutch thus the slippage.
Sure, sort of a long shot.
Fix the mount.
If the clutch really slipping in 5th and 6th gear cause of old age and normal wear and tear you'll know soon enough.
I was Porsche dealer service depart. some few months ago (before June IIRC) and came across a Turbo in for a new clutch. The stock one gave up. I forget the figures but the tech told me the owner had the engine breathed on a bit and the engine was putting out more HP and the stock clutch was just not up to it. As I said I don't remember the figures but the stock clutch is not good for much more HP/torque. 30hp and an equal amount of torque? Possibly. Very likely ok. 50hp/50ftlbs of torque? Pushing it. 75 or higher... Probably not.
Sincerely,
Macster.
10-28-2009, 11:15 PM
#18
Instructor
Thread Starter
OEM or similar clutch seems to go for 600-900. An improved stage 2'ish clutch seems to run around $1200-$2000.
My indy in Atlanta charges $500 to install a clutch. He used to work for Porsche, now works for BMW. He works on my 7-series as well.
My indy in Atlanta charges $500 to install a clutch. He used to work for Porsche, now works for BMW. He works on my 7-series as well.
10-29-2009, 10:35 PM
#20
Instructor
Thread Starter
The verdict is in. Clutch is fine. It had a broken gearbox mount. Replaced today. No more herky jerky shifts and clutch doesn't slip in any gear under any load.
Example Symptom:
The car would lightly bounce back and forth when trying to maintain a constant speed if stuck in traffic. If I would let off the gas slightly...and then gently ease back into the throttle, maybe accelerating 5mph or so...the car would get a little jerky until I gave it more gas.
The new one was a 997 part. Maybe updated bushings?
$268.88 installed
Part #99737503303
Example Symptom:
The car would lightly bounce back and forth when trying to maintain a constant speed if stuck in traffic. If I would let off the gas slightly...and then gently ease back into the throttle, maybe accelerating 5mph or so...the car would get a little jerky until I gave it more gas.
The new one was a 997 part. Maybe updated bushings?
$268.88 installed
Part #99737503303
10-30-2009, 01:57 AM
#21
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The verdict is in. Clutch is fine. It had a broken gearbox mount. Replaced today. No more herky jerky shifts and clutch doesn't slip in any gear under any load.
Example Symptom:
The car would lightly bounce back and forth when trying to maintain a constant speed if stuck in traffic. If I would let off the gas slightly...and then gently ease back into the throttle, maybe accelerating 5mph or so...the car would get a little jerky until I gave it more gas.
The new one was a 997 part. Maybe updated bushings?
$268.88 installed
Part #99737503303
Example Symptom:
The car would lightly bounce back and forth when trying to maintain a constant speed if stuck in traffic. If I would let off the gas slightly...and then gently ease back into the throttle, maybe accelerating 5mph or so...the car would get a little jerky until I gave it more gas.
The new one was a 997 part. Maybe updated bushings?
$268.88 installed
Part #99737503303
12-13-2009, 01:54 PM
#23
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hey lysoleverywhere,
i just had same problem of slippage in 5th and 6th gear at about .8 to 1.0 boost. how did you test clutch and can you be more specific about gear box mount location?
i just had same problem of slippage in 5th and 6th gear at about .8 to 1.0 boost. how did you test clutch and can you be more specific about gear box mount location?
12-14-2009, 01:23 AM
#26
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i forgot to mention the car sat for about 5 days and the temp. really dropped last few days. later on that day i pushed the car, but no slips in any gear or during down shifts. temp rose alittle bit later in the day as well
09-15-2013, 11:21 AM
#27
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Interestingly, I worked a night shift and my car-'02 with an EPL flash had some slippage accelerating on the interstate in 4th. The ambient temperature was 54 degrees F. Last night the same thing happened at 57 degrees. The engine was fully warm both times. I did not notice at what boost this was happening but I have seen 1.3 Bar at full boost. It was at 3500 rpm to 4000. I have also noticed from the time I purchased the car-3/13, that I have a similar issue when crushing on the highway with what feels like a subtle stumble when going from on throttle to off throttle. It seemed like a programming glitch to me until I read this thread. Could this be a transmission mount or overloaded clutch? I currently have 41K on it and the clutch is original.
10-03-2013, 12:08 AM
#29
$500 for a clutch job is a GREAT deal.
10-25-2013, 02:44 PM
#30
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I replaced the transmission mount today with the 997 Turbo part, doubting my skills with window weld and as it's a relatively cheap part. The on/off throttle issue is gone, it shifts smoother but I still have clutch slippage. It's not as severe as before. It started at 4200 rpm in 4th instead of 3500 and didn't last as long. The air temp was 49F. Could this just be that the engine is making significantly more power with the denser air and it being flashed? I understand that the flash brings it to 490 hp. Thoughts?