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turboslut

Over rev - any thoughts?

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All,

I am looking to own a 997tt soon. I have been reading up on everything and am using the over rev report as my first filter.

I had a dealer send me report for a vehicle I am interested in and the attached is what I got. Is this possible? Legit?

Total operating hours are 2003

Vehicle is a 2007 6 speed manual.

post-97577-140856319353_thumb.jpg

Any help is appreciated

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Why don't you believe it's possible?  It has one very serious range violation.  Over revs that high probably a result of a missed shift.  Range 1 and 2 violations aren't anything to get worked up about on the 997.  It's the higher range violations that would void warranties, etc.

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That report is fine. The over-revs in Range 1 & 2 or normal from strong accelerations into the rev-limiter. The 4 ignitions in Range #3 are not a big deal since they also happened about 466 hours ago (I'd guess about 15,000 miles......466 hours x 32 mph average).

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These are over-revs. There has been over-rev hysteria, alerting potential  serious engine damage due to high over-revs caused by missed shifts. Sure engine damage can definitely occur as a consequence of missed shifts. However, not all over-revs even in high ranges are the results of missed shifts. Therefore the question here is the significance of 1 ignition over-rev each in ranges 4, 5, and 6. In the context of 3 ignitions per each RPM, One ignition would amount to only a small fraction of one second, considering the high RPMs extant in the above ranges. There is NO way to attribute these to missed shifts (manual transmission!). It is humanly impossible. It is more likely due to the computer/software flukes/aberrations or other unknown (at least to me)  mechanisms.

 

It is well known that Porsche does not CPOs the cars with pathological over-revs. When I bought my 2003 996 several years ago, it was certified by Porsche even though it had 1 ignition over-rev in the range 2 (please note that in 996 there were only 2 ranges: one and two); I drove the car for 6 years with NO engine problems. Even the original IMS bearing was in excellent shape before I replaced it for prophylactic reasons.

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Mine has 1 in range 4, 3 in 5, 3 in 6, pay it no mind, at that low level it is likely to be a software glitch rather than a real issue. Start to be concerned if the are something in the line of 30 in range 6, then be concerned. So many people are paranoid over this. Aehsani is quite correct.

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The Mezger can take a flogging but there is no "software glitch" that I'm aware of.  Missed shifts are generally what would get you to such a high RPM (the rev limiter kicks in way before you would be in serious violation gaining RPM using the throttle).

 

No one here is saying you should live and die by this but if you are buying a car, looking at this can give some general indication of how the car was driven (sunday driver vs track).  You should always be paranoid when you buy a car.  Aside from that, I don't know too many owners that frequently obsess over these numbers........

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Actually the range 1 and 2 are legit. and no issue.  Based on the engine having revolutions, it seems impossible that you can have 1 revolution in three categories at once?  The engine would have to have a rev in one range and more to get to the next.  I have seen similar on my tuned cars ( Tiptronic...so no downshift)....And when I asked the expert tuners, they suggested it is an anomaly.

 

At any rate, this report is nothing to be concerned with in my opinion.

 

Good luck,

DC

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Each of those listed ranges refers to a specific range of RPM.  So in the case of the engine hitting very high RPM and dramatically exceeding what's tolerated in spec, presumably you would get ignitions in the lower ranges "on the way up" as the engine worked its way up to high RPM.  You could be right but I've never seen anything convincing that there's a software bug or that this ECU information is generally not accurate or trustworthy.  I would imagine that metering RPM has to be one of the more accurate things the car needs to do and that the tolerance for error would be engineered to be very low.  

 

There are folks out there who have had their warranties voided by Porsche because of the like so there's obviously some merit to it.  I'm not at all saying that's the case of the original poster or even that it occurs that often, but if you will look around you can see it's happened to more than one person at more than one dealer.  Anyway, not a shot at you but I think most tuners are full of it.

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