I had a PPI done on a car and the dealership came back and indicated that it was heavily over-revved, and driven very, very hard. I asked for the actual results and they faxed me the info. Can someone interpret?

15.09.2006 [yesterday's date]
17:43:58 [time - probably some othe timezone since it was done in the middle of the day]
911 (996) DME Vehicle Data
Number of ignitions, range 1
655535 488.3 h
Number of ignitions, range 2
4646 423.3h
Operating hours counter
489.0
Vehicle ID number
...(more but just stuff like engine type, engine number, etc.)


Is the number of ignitions, range 1 the number of times the car hit the rev limiter? What does the 488.3 h mean?

How about range 2? Is that the mechanical over-revving that they indicated?

I am now curious on what my current car's results would look like!

Anybody else have their cars info and if so, what are your numbers?

Thanks.

 

The hour data is when the car was over-revved. It is quite obvious that the first type 1 overrev was when the car only had 6 hours on it.Not too uncommon as the new driver probably wasnt used to the power. The first type2 over rev was 66 hours after the car was new, 489 hours - 423 hours= 66 hours. I am sure you now that the counter tracks actual cylinder firings in the over rev zone so that is why the numbers are so high, you do not have to be in the range very long for the numbers to accumulate rapidly. Type 2 isnt good as far as warranty , but given they happened a while ago, it is safe to assume if the valvetrain was damaged from them , symptoms would have arised by now. As far as type 1 I have heard some dealers think it isnt an issue because the ECU is protecting the engine, but others insist it is a problem. Kevin

 

At 7000 rpm 350 ignitions occur per second. This car spent over 30 minutes in type 1 overrevs and 13 seconds in type 2. This seems excessive to me.

 

The dealer where the PPI occurred indicated that it was excessive and if this was presented to them for an engine warranty claim, it is most likely going to be rejected based on abuse.

Correct me if I'm wrong but Type 1 is when you hit the rev limiter as the rev's climb. Probably shouldn't be too big of a deal from time to time, but 30 minutes of time at redline seems pretty high. That's a very long time of banging against the rev limiter (if I understand the data correctly).

Type 2 is mechanical over-revving right? Doesn't that mean that they were going too fast for a certain gear (like missing a shift or downshifting when the speed is too high for a certain gear). 13 seconds probably means that a shift was missed at least 13 times wouldn't it since it shouldn't take more than a second to be out of the overrev condition (unless it was overreved for a long time)?

KPG-thanks on the interpretation of the hours data. I guess it isn't very useful since it only tracks the first occurrence of the overrev and not when each occurs (or even when the last one occurred).

I ended up passing on this car especially since the rotors were cracking - another sign of pretty aggressive driving (which I wouldn't mind, if not for the Type 2 overrevs and large amt of time for the Type 1).

Otherwise, it looked pretty good!

 

Now there is an interesting piece of info: cracking rotors. You would be hard pressed to crack rotors on the street, you just cannot create the heat for the durations needed to crack them. My rotors are cracked as well , but I track quite often. Given this info, the ECU data isnt totally unreasonable , although it seems like the previous owner must have banged the limiter nearly every shift. I have hit my limiter now and then as well. Kevin

 

Could 30 mins of type 1 be a result of an ECU flash allowing for a higher red line?

 

Good question. Kevin

 

Actually, I think that both Type 1 and Type 2 could be a result of an ECU flash to a higher redline. The ECU monitors the ignitions that occur at a certain RPM range. If you are able to rev higher than stock, that would cause the ECU to indicate that it has spent time over redline.

The next question I had is whether there was a maximum number that it can track. I have seen 2 cars with '65535' as the number of range 1 occurences so I think it maxes out its log at some point. It would seem strange that they had EXACTLY the same amount of type 1 occurences.

If this particular car was chipped, it would seemt then that you would have a higher amount of Type 2 over-rev...if you had a 7k rpm redline, wouldn't you hit that more frequently than a dozen times?

 

256x256= 65536. 65535 is probably the biggest number the chip can record.
Earlier when I said the car ran 30 min in range 1 overrev I was using the number 655535. 65535 ignitions take about 3 minutes, not 30. 3 minutes in range 1 with a chipped car is not so bad.

 

if it's not a chipped car though...the Range 2 revs (13 seconds past redline) is still a problem.

 

so then we gotta know if its chipped or not.

 

that particular one was bone stock. But it could've been chipped and re-flashed to stock. I guess the whole ECU analysis becomes moot in the world of aftermarket flash programming...

Though I wonder how the dealer would treat a warranty claim on a car with these kinds of numbers. The dealer that did this analysis indicated they would most likely turn down warranty work for an engine that showed these kinds of numbers.

Of course, I'm sure there will be an opportunity for some genius to reflash the CPU to reset this counter...

 

Some tuners state that the flash can not be detected by the dealer... but then they( evoms) do not increase the redline...

 

Perhaps some tuners can clarify. I thought that I spoke with evoms and that they did increase redline to over 7000 rpm on some of their kits.

 

mine is 65535 also.

range 2 is 881 (that's what happens when you let a friend drive the car)

Me to friend "the only way to lunch a 996 TT engine is to change into the wrong gear so be careful"

friend "Ok no problem"

1 minute later he changes from 4th to 3rd while accelerating.

fortunately he didn't let the clutch all the way out.