I took an 06 C4 for a PPI similar to what would be done in a CPO and it detected over revs.

Here's the data:
Range 1 - 172
Range 2 - 26
Range 3 - 1
Range 4 - 1
Range 5 - 1
Range 6 - 0

I would like some help in understanding what the ranges mean, and if I should be concerned before making an offer for the car.

 

I think that must be an error. Logically it would not possible (on a true mechanical over-rev) to have 1 ignition recorded in ranges three through five - almost by definition, there must be more ignitions in R4 than R5 and more in R3 than R4 etc. I can't tell you how that one ignition got there in ranges 3 through 5, but it is highly unlikely that it was the result of a mechanical over-rev.

 

This is what the "Vehicle analysis log" printed by the technicians states:
Number of ignitions at speed > max speed, range 1: 172
etc...

 

i dont understand. Doesnt our cars have rev limiters?

 

Yes they do but they are limited (pun intended) in what they can do. They do not limit missed shifts.

 

I'm not sure, but I believe that number is how many time the rev limiter was hit vs over rev. That being said, hitting the rev limiter in 5th, how fast was he/she going to do that????

 

Thats not what it means. The ranges are RPM ranges in what I believe are 100 rpm increments over redline.

Edgy help!!!!!!!!

 

The overrev report does not indicate what gear the car was in when the overrev occurred. I think you're misinterpreting what the "range" means. That indicates the rpm range (how much "over" it was)

 

Looks great, you have nothing in 3+ areas. That '1' is a glitch, ignore it.

 

I don't see anything to worry about with these numbers. Those single ignitions in ranges 3, 4, 5 look more like instrumentation failures than an actual over-rev. If the engine was really turning that fast, I'd expect to see more than a single ignition in those ranges as the momentum of the spinning crankshaft wouldn't speed up/slow down fast enough.

Those numbers in range 1 and 2 are pretty low and nothing to worry about.

 

Try a search on over revs range and you'll get lots of detail on what all this means. There are 3 ignitions in 1 revolution of the engine. So really, I don't think 1 instance is even possible as it would be 1/3 of one RPM. There have been many reports of 1's in all ranges right up to 6.

We do have rev limiters, but if you "bounce" off the redline you are likely to see Range 1 and 2. The harder you drive, the more you'll see it. This car forunately didn't see a money shift.

I bought an 05 Boxster S from a dealer CPO and had him document the Range 1 and 2 over revs as part of the contract / CPO process. Reason being is I didn't want to end up in a warranty argument some day in the future if they say "Hmmm, looks like you abused the engine..."

 

When I got my car at PPI seller and I discussed DME readings and service manager told that they really get concerned with 4+ ranges showing up. Range 3 is a danger zone but does not affect warranty claims, well, from what I was told.
All those decisions as I understand are not up to the particular dealer but up to PCNA when they make a decision if any particular catastrophic engine failure is getting covered or not. In all other situations no one even looks at DME numbers.

 

That looks fine to me. Mine looked like this when I bought my S with 14,000 miles

1: 1418 / 675h
2: 451 / 675h
3: 199 / 675h
4: 69 / 570h
5: 0
6: 0

I bought it with these numbers, and the engine has been fine for my first 5,000 miles with the car. I drive it pretty hard and can't appreciate any problems. Also it passed the inspection to be sold as a CPO car.

Judging by the numbers you posted, your car has been babied. I think it is a keeper.

 

We have discussed this many times the past several months. There is some great info in a few past posts.

A 997-1 DME records the following rev ranges:
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

 

BTW, I picked up this little nugget somewhere.

Is it true? Thanks in advance.

Referencing our modern engines and supposedly the rev limiter is there to get 100K road miles out of the car:

"Porsche engines will tolerate up to 10K RPM."