Help deciphering over revs on CGT:
Sep 18, 2009 | 07:39 PM
#21
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Joined: Aug 2007
Posts: 1,909
I am no genius when it comes to reading those things, but I'm curious to have a look. PM sent.
Sep 18, 2009 | 07:55 PM
#22
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It appears to only state the duration that the rpm occurred. In this case, maximum number of ignitions at whatever value flags a stage 2 fault.
I've seen reports on other German cars that were older where it clearly indicated the maximum rpm reached. I don't see why it doesn't come up in this printout.
Could any Porsche techs chime in? I am by no means trying to alarm you, as several different dealers signed off on it, but I'm pretty curious.
I've seen reports on other German cars that were older where it clearly indicated the maximum rpm reached. I don't see why it doesn't come up in this printout.
Could any Porsche techs chime in? I am by no means trying to alarm you, as several different dealers signed off on it, but I'm pretty curious.
Sep 18, 2009 | 08:06 PM
#23
Thread Starter
| Teamspeed Junior Member
Joined: Jan 2008
Posts: 65
From: Metro NY
It appears to only state the duration that the rpm occurred. In this case, maximum number of ignitions at whatever value flags a stage 2 fault.
I've seen reports on other German cars that were older where it clearly indicated the maximum rpm reached. I don't see why it doesn't come up in this printout.
Could any Porsche techs chime in? I am by no means trying to alarm you, as several different dealers signed off on it, but I'm pretty curious.
I've seen reports on other German cars that were older where it clearly indicated the maximum rpm reached. I don't see why it doesn't come up in this printout.
Could any Porsche techs chime in? I am by no means trying to alarm you, as several different dealers signed off on it, but I'm pretty curious.
Sep 18, 2009 | 08:12 PM
#24
Thread Starter
| Teamspeed Junior Member
Joined: Jan 2008
Posts: 65
From: Metro NY
u aint kidding. Wire transfer was contingent on all pieces of luggage, window sticker, and full service history.
Sep 18, 2009 | 08:14 PM
#25
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| Teamspeed Junior Member
Joined: Jan 2008
Posts: 65
From: Metro NY
response from a guy on rennlist:
range 1 refers to number of ignitions (spark plug firings) that occur in the rev limiter range - not harmful.
range 2 ignitions occur when the rev limiter can't stop the madness, i.e. 5-4 downshift intended, 5-2 occured instead and clutch was released. less than 1k sparks in that range wouldn't worry me, sounds like someone just mis-timed a downshift by a hair. a drag race situation, however, wherein someone were going for a WOT 2-3 upshift and got 1st instead... that would be a different deal, but would typically result in thousands of ignitions in the upper range. and a broken motor.
29.5mm is about 50% of clutch - new is ~30.5-31.0, repl rec'd @ 28.0.
range 1 refers to number of ignitions (spark plug firings) that occur in the rev limiter range - not harmful.
range 2 ignitions occur when the rev limiter can't stop the madness, i.e. 5-4 downshift intended, 5-2 occured instead and clutch was released. less than 1k sparks in that range wouldn't worry me, sounds like someone just mis-timed a downshift by a hair. a drag race situation, however, wherein someone were going for a WOT 2-3 upshift and got 1st instead... that would be a different deal, but would typically result in thousands of ignitions in the upper range. and a broken motor.
29.5mm is about 50% of clutch - new is ~30.5-31.0, repl rec'd @ 28.0.
Sep 18, 2009 | 08:15 PM
#26
Thread Starter
| Teamspeed Junior Member
Joined: Jan 2008
Posts: 65
From: Metro NY
response from renntech:
RANGE 1, 8400-9000
RANGE 2, over 9000
As there are 5 ignitions per revolution, then 7551 ignitions=1500 revolutios. At 9000rpm this represents a total of about 10 seconds of over-rev in the life of the car. Spirited driving occasionally? 825 ignitions=165 revolutions=1second, so maybe one or two premature downshifts. It wouldn't worry me, but then again I doubt if I will be in a position to be looking at buying a CGT!!
The workshop manual says: "If measurement -a- is less than 28 mm, the clutch must be replaced". Not sure what it starts out at though.
RANGE 1, 8400-9000
RANGE 2, over 9000
As there are 5 ignitions per revolution, then 7551 ignitions=1500 revolutios. At 9000rpm this represents a total of about 10 seconds of over-rev in the life of the car. Spirited driving occasionally? 825 ignitions=165 revolutions=1second, so maybe one or two premature downshifts. It wouldn't worry me, but then again I doubt if I will be in a position to be looking at buying a CGT!!
The workshop manual says: "If measurement -a- is less than 28 mm, the clutch must be replaced". Not sure what it starts out at though.
Sep 18, 2009 | 08:30 PM
#27
Teamspeed Pro
Joined: Aug 2007
Posts: 1,909
response from a guy on rennlist:
range 1 refers to number of ignitions (spark plug firings) that occur in the rev limiter range - not harmful.
range 2 ignitions occur when the rev limiter can't stop the madness, i.e. 5-4 downshift intended, 5-2 occured instead and clutch was released. less than 1k sparks in that range wouldn't worry me, sounds like someone just mis-timed a downshift by a hair. a drag race situation, however, wherein someone were going for a WOT 2-3 upshift and got 1st instead... that would be a different deal, but would typically result in thousands of ignitions in the upper range. and a broken motor.
29.5mm is about 50% of clutch - new is ~30.5-31.0, repl rec'd @ 28.0.
range 1 refers to number of ignitions (spark plug firings) that occur in the rev limiter range - not harmful.
range 2 ignitions occur when the rev limiter can't stop the madness, i.e. 5-4 downshift intended, 5-2 occured instead and clutch was released. less than 1k sparks in that range wouldn't worry me, sounds like someone just mis-timed a downshift by a hair. a drag race situation, however, wherein someone were going for a WOT 2-3 upshift and got 1st instead... that would be a different deal, but would typically result in thousands of ignitions in the upper range. and a broken motor.
29.5mm is about 50% of clutch - new is ~30.5-31.0, repl rec'd @ 28.0.
response from renntech:
RANGE 1, 8400-9000
RANGE 2, over 9000
As there are 5 ignitions per revolution, then 7551 ignitions=1500 revolutios. At 9000rpm this represents a total of about 10 seconds of over-rev in the life of the car. Spirited driving occasionally? 825 ignitions=165 revolutions=1second, so maybe one or two premature downshifts. It wouldn't worry me, but then again I doubt if I will be in a position to be looking at buying a CGT!!
The workshop manual says: "If measurement -a- is less than 28 mm, the clutch must be replaced". Not sure what it starts out at though.
RANGE 1, 8400-9000
RANGE 2, over 9000
As there are 5 ignitions per revolution, then 7551 ignitions=1500 revolutios. At 9000rpm this represents a total of about 10 seconds of over-rev in the life of the car. Spirited driving occasionally? 825 ignitions=165 revolutions=1second, so maybe one or two premature downshifts. It wouldn't worry me, but then again I doubt if I will be in a position to be looking at buying a CGT!!
The workshop manual says: "If measurement -a- is less than 28 mm, the clutch must be replaced". Not sure what it starts out at though.
Very informative. For what it is worth, this motor was designed to be a 10k+ rpm race engine. I have to imagine that it can easily withstand a couple of light over revs.
Sep 18, 2009 | 10:36 PM
#29
Teamspeed's Official Shaikh
Joined: Jan 2008
Posts: 2,291
From: Bahrain
Ricky to start Congrats on buying the best car out there
There should be no problem with revs you have listed above but if you want to be very sure you can have the workshop do a compression test and that will indicate if you have any bent valves from a type2 over rev.
The valves will always bend in a bad over rev and the cylinders will lose compression due to none perfect sealing of the valve on the valave seat. If the engine idle and run fine with good power it should be ok and I personally dont think you have that problem.
The clutch should not wear in a low mileage car unless the previous owner did get used to the auto throttle or anti stall which helps the driver of the CGT from stalling. This function works when you releas the clutch padel without using the throttle. Check it out and once you get used to it the car will be a dream to drive.
I hope answered some of your concerns
There should be no problem with revs you have listed above but if you want to be very sure you can have the workshop do a compression test and that will indicate if you have any bent valves from a type2 over rev.
The valves will always bend in a bad over rev and the cylinders will lose compression due to none perfect sealing of the valve on the valave seat. If the engine idle and run fine with good power it should be ok and I personally dont think you have that problem.
The clutch should not wear in a low mileage car unless the previous owner did get used to the auto throttle or anti stall which helps the driver of the CGT from stalling. This function works when you releas the clutch padel without using the throttle. Check it out and once you get used to it the car will be a dream to drive.
I hope answered some of your concerns
