Hi Forum members, I am new here and my name is Jan. I am currently looking at purchasing an 06' convertible, one owner, complete service history, 29k miles. The road test and mechanical check at Porsche during the PPI came out great but they found over revs in 1 to 5 range. What confuses me are the readings in 4 and 5 with only just one ignition. How is that possible? Maybe a reading error? I'm am also wondering if I should have Porsche conduct a pressure test but this will add another 450.00 to the PPI charge. What do you think? Any help and thoughts are greatly appreciated. Please see the picture for the exact reading. Many thanks! Jan

 

There have been a few threads on this before. The consensus seems to be the 4 and 5 with only 1 ignition in them are glitches, so don't worry about it. Ignoring the 4 and 5 this report is super clean. For reference I have over 40k overrevs in range 1. Your potential car was driven by a grandma.

 

haha, damn you beat me by 10k.

that's a clean car. yep, the 1's are ghosts, not real. and even the 8 and the 2 look a bit ghosty to me. ok, 8 in R2 sure, but to record a 2 - and only 2, mind you - in R3, then go BACK down thru R2...but still end up with only 8? i call shenanigans.

 

Pardon the dumb question but does bouncing the engine of the rev limiters really matter? I think I've done that without any consequences in every car I've owned since they started using electronic governors

 

A lay man's interpretation:

There are 3 ignitions in 1 revolution and there are 120 revolutions in a second. That means there are 360 ignitions per second.

So with the above values, you can determine how long the over rev was by dividing number of ignitions by 360.

So in range 1 (greater than 7,300 RPMs, but less than 7,500 for a Carrera): the over rev lasted a whopping 3 tenths of a second (124/ 360 = .34)

Obviously the rest of the values are very insignificant. And it's not possible to have 1 ignition, so those are misreads.

Each range is incrementally higher into the redline & disastrous (from possible to likely to definite engine damage). So range 6 which equates to greater than 9500 RPMs for a Carrera means "ENGINE DAMAGE HAS GENERALLY OCCURRED".

The car in this example is as healthy as can be.

Also, dividing ACTUAL MILEAGE / TOTAL OPERATING HOURS = AVG SPEED OF CAR

Here is general interpretation of AVG SPEED:

< 30: garage queen, mostly short trips
30-50: Mostly highway driven
> 50: Could have been aggressively driven/tracked

I don't see the total operating hours, so can't make that calculation.

 

not really dumb. but define "matter". you will def record R1 hits. perhaps not every bounce off but it will happen from time to time. even a PDK can generate R1 hits. but in general, R1 is not that bad at all and that's what the nanny is there for - to stop it from going to R2 and up.

 

For the record you can hit up to range 3 by bouncing off the limiter. It just depends on how hard you hit it. Personally I don't see any problem with range 3 over revs.

 

Ya know, i've heard something similar (from a 20yr veteran stealership tech and from a local well respected indy, so i guess, at least 2 diff "reliable" sources)...it's not really that the engine can't take the higher revs, but it becomes a problem with how fast it spins up under load. i.e. 8000rpm is not necessarily bad for a short time but when it spins from, say, 3k to 8k+ in a fraction of a sec, that is how stuff breaks, etc.

again, i'm no rocket surgeon, nor know much more about engines than putting gas in...just what i've been told.

 

I added one important piece (in blue) that was missing in the initial sentence of a very good write up of ignitions and rev ranges.