cbb

Looked at a 2011 997.2 S and got over rev report. Sounds like this car has been abused and I should run, not walk away from purchase

Data below, number of ignitions at speed > maximum speed

Range 1-679
Range 2- 17
Range 3-7
Range 4-32
Range 5-80
Range 6- 503

Operating hours counter reading at overspeed 1502.97
Operating hours counter 1698.74
Odometer 75588 km

what are your thoughts?

bgoetz

That DME seems incorrect. There are way too many range 6 and not enough range 4/5 for it to really make sense.

jamesinger

Technically, it is impossible to have 503 ignitions in R6 without that many + in the lower ranges, so something is wrong with the reading (i.e. you have to go past R2-5 to get to R6, so there should be that many + in those ranges for it to be correct).
I would find out how they ran the report and run another one, something is wrong.

cbb

It was run at Porsche Dealer. On laptop computer. Vehicle analysis log. 74 page report

Tj40

You're going to have a lot of debate regarding the physical possibility of the report. Regardless you are going to buy a car with rev's in range 6. I would note <200 hours since the over-revs so unless you want to take the risk I would run and find another car with a clean report.

My 2c

doclouie

Yes that report is possible. I will try to dig up an old post. That being said there are a lot of rev 6’s and that is a concern. If it is going to break it would most likely be within about 100 hours, but it could have weakened it so it fails later. If you proceed make sure that is factored in or just walk away.

qikqbn

I would like to see how this report is possible... because it looks impossible to me. That seems crazy to me when you think that an engine spins up to a peak rpm and then returns to a lower rpm. Rpms are recorded more or less like a mountain peak or bell curve. There should always be the least amount of ignitions or time spent at the "peak" or highest range recorded, in this case range 6. The ranges underneath, 1-5, will record the curve as the rpm tach needle sweeps through the ranges on the way up to peak and also as the tach needle sweeps back through on its way down the rpm range spending more time in the lower ranges.. Can't imagine how it would jump through ranges. Either it's a glitch or someone has been messing around with trying to adjust it.

cbb

Upon further investigation, it appears engine has been replaced!

doclouie

Ranges 1-6 are not equal in RPM band so you cannot compare one range to another as that is apples to oranges. See post 16 and then down to post 21 and you will see what I mean.

https://rennlist.com/forums/997-foru...nky-dme-2.html

doclouie

How many hours ago?

qikqbn

ok.. that graph is an interesting way of looking at it based on what I think would apply to some one who fully committed and money shifted to the point where the engine zings quickly through lower ranges and holds in range 6 for a few seconds and then quickly drops down through the rpm range.

but the OP's DME range 3 looks very strange with only 7 ignitions... even in a committed money shift scenario like I described. Still, it's a very interesting idea on how this could possibly happen.

Range 1-679
Range 2- 17
Range 3-7
Range 4-32
Range 5-80
Range 6- 503

cbb

Not sure when engine replaced. Obviously decided not to purchase.

GoldenGorilla

Like doclouie says, it could hit those Range 6 numbers while decelerating down from a missed shift. You cannot reach range 6 by use of the gas pedal, it can only be done through a missed shift. But the engine RPM could be driven up faster than it compression brakes down and as doclouie shows, the ranges are not equal. The curve doesn't have to look like a bell curve. It could look like the Whitney group of the eastern Sierras. (Very much steeper on one side than the other).

jamesinger

^^^ So are you saying, you massively miss a shift, and then pop out before going back down through R5-1? I understand that.

sandwedge

Did you ask them how it's possible to have 503 in range 6 and just 7 in range 3? That's what I can't figure out among other weird things in that report.