Jul 22, 2008 4:45:56 PM
- pawelmontana
- Junior
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- Loc: Europe
- Posts: 122, Gallery
- Registered on: Feb 19, 2007
Crown
Board: Porsche - 911 - 997
Language: English
Region: Worldwide
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Jul 22, 2008 5:28:49 PM
- jeffbco
- Pilot
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- Loc: Denver
- Posts: 494, Gallery
- Registered on: Mar 18, 2006
- Reply to: pawelmontana
Re: Overrevs question
Quote:
pawelmontana said:
I was told by my dealer that my engine had 83 points in category 3 overevs recorded. What does it mean in simple English? How dangerous is this?
FYI, my engine is running perfect.
This is from another board:
Ranges 1-3 are just 200 RPM's apart in a spread for each range just for mainly info on how you are bumping the rev limiter. Ranges 1-3 are common for just winding up to the rev limiter at 7200 , inertia will generate up to range 3 at this time. This will depend on your driving.
Range 4 is 500 rpm and encompasses two different types of engines, ones that red line at 8200 and those that shouldn't. Basically all the 987 and 997 other than the X51 or GT3 that red line at 7200. This range shows a ID on which engine or mod is in the car between the two.
Range 5 is considered the gray or warranty void area for both engines in question and is generally not good for Porsche.
Range 6 Is a void of warranty and encompasses the 10200 rev limit. The 10200 is the point that all the 987 and 997 engines will succumb to valve float. The 10200 has a separate minimum classification in the DME. After this range is tripped it will record ANY rev above it.
I should also mention that the 996 and 986 had a range 1 and 2 with the same 10200 max.
Best,
Scott Slauson
PCA Technical Expert
If I did the math correct, your reading of 83 equates to about 0.21 seconds at 7,700 rpm - 21/100's second - difficult to count that fast. As Scott said, inertia could take you into range 3 before the rev limiter can do its thing.
Re: Overrevs question
The info below is from the Durametric website (they make diagnostic software)
"The 6 ranges can be broken down as:
Range 1: 7300-7500 RPM
Range 2: 7500-7700 RPM
Range 3: 7700-7900 RPM
Range 4: 7900-8400 RPM
Range 5: 8400-9500 RPM
Range 6: 9500-11000 RPM
The number is the number of ignitions in each of these ranges.
The factory PIWIS tool does not display the hours for each of these ranges but the informaiton is available so we display it here. The hour indicates the last operating hour that this range occured in."
"The 6 ranges can be broken down as:
Range 1: 7300-7500 RPM
Range 2: 7500-7700 RPM
Range 3: 7700-7900 RPM
Range 4: 7900-8400 RPM
Range 5: 8400-9500 RPM
Range 6: 9500-11000 RPM
The number is the number of ignitions in each of these ranges.
The factory PIWIS tool does not display the hours for each of these ranges but the informaiton is available so we display it here. The hour indicates the last operating hour that this range occured in."
Re: Overrevs question
What I dont get is the inertia explanation. In my mind, as soon as the energy (fuel flow) is cut off no further rise in engine speed is possible, nor is an increase of vehicle speed.
I think the RPM limit kicks in gradually in the ranges 1-3, as I have quite a few in those ranges.
I think the RPM limit kicks in gradually in the ranges 1-3, as I have quite a few in those ranges.
Re: Overrevs question
Quote:Yes the engine may be limited but the wheels are still turning as is the engine. Vehicle speed doesn't immediately react to rev limiter cut off.
Moppe said:
What I dont get is the inertia explanation. In my mind, as soon as the energy (fuel flow) is cut off no further rise in engine speed is possible, nor is an increase of vehicle speed.
I think the RPM limit kicks in gradually in the ranges 1-3, as I have quite a few in those ranges.
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