Should I be worried by the result of this DME????

I got the DME read on my car and the over revs look like this:

Range 1: 14,445 @1219h
Range 2: 1424 @1219h
Range 3: 100 @ 856h
Range 4: 3 @ 706h
Range 5: 0
Range 6: 0

Current opperating time is 1224h (I hit the limiter at 1219 so that was me) car has 32k miles was bought at 26k miles (one previous careful? Owner)...

Is it even possible to have that few Range 3 and Range 4 over revs or just a logging glitch on the ECU!?

By my calculation Range 3 would have been about 0.25s and range 4 would be 0.008sec....??

 

Range 3 would be about 33 revs and 4 would be 1 rev. I wouldn't worry about it.

 

wow I am not smart enough for this.......

 

They happened so long ago not a big deal in my opinion.

 

hehe, you are not along. Would some one please layout the formula ? Thanks

 

If its still running forget about it!

 

Hi! Here is a thread I posted last year when I bought my 997S. My car had similar over revs and has been a great car over the past year and a half.

dme-over-revs-ranges-3-4-5-reported-ok?

Read through the thread and hopefully it will help you understand the situation. During a stage 4 over rev, there are approximately 400 ignitions per second, so your 3 ignitions in stage 4 is less than 1/100 of a second. (8,000 rpm / 60 seconds x 3 ignitions per revolution = 400 ignitions per second in stage 4).

The 997 has a rev limiter, so the over rev was most likely done in a missed down shift. Very minor and not a sign of abuse. If you do DE's it will be easy have this happen.

If all checks out with the car buy it, drive it (and don't baby it) and most importantly have fun! Post some photos!

Don

 

Did that help guys?

Most replies to my thread (that asked the same question) took an emotional approach and told me not to buy the car. Others like Jhbrennan, Northvan and KKMoto took an analytical approach.

Doing the math indicated the over rev was not a sign of abuse. These are race track caliber vehicles and I don't believe an over rev is a sign of abuse. The over rev is just a missed gear where the driver pushed in the clutch as quickly as he realized the bad down shift.

 

Thanks for the reply guys....car has been faultless so far (touch wood).

For me a car to have such few ignitions in a range means that either its a glitch OR the rev limiter just touched that range!? So in this case having 3 ignitions means the there was one revolution. To have one revolution only and register a range 4 the car probably revved to exactly 7,900 revs or 7,901 revs!? Similarly to have only 33 revolutions in range 3 is probably just hitting the rev limiter in sport mode (kicks in between 7,300 and 7,500). Does that make sense?

Initially there was the whole hysteria of IMS failure and then people started talking about cylinder scoring, now both of these topics have died away and one people are talking about over revs as the next paranoid point......it's hard to enjoy ownership sometimes. Basically every time you are out of the car it's paranoia and every time you are in it it's great fun and love! Like being married to a beautiful lady...

What do you guys think?

 

I picked 8,000 rpm for the stage 4 to make the math easier from this table:

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

I am amazed that 8,000 rpm the crank is spinning 133 times each second and firing 400 times each second.

 

By your own calculations you have answered the question of relevance. They are not. As for rev limiter, that's what it is there for. Enjoy the car and if you have a catastophic over rev you won't need to ask anyone about it. Think big bang theory, it will be kind of like that only without the stars.

 

I m no expert but I agree if you damage the engine on an over rev situation that you would know about it right away...
As talked about before on this site, I m not sure the rev limiter protects the engine on down shift over rev situations.

 

Rev limiter will not protect from a mechanical over-rev (missed shift).