Thanks for the great info Tom. It’s great to have the pros weigh in on these questions. Here’s one for you – I purchased a used 2008 TT with 16,000 miles, 580 hours and the following over revs:
Range 3 342 at 571
Range 4 148 at 424
Range 5 13 at 204
The car runs great, no oil leaks or oil consumption, no strange engine sounds and the selling P-Car dealer CPO’d the car even with those over revs disclosed. Here’s my question – I drive conservatively and as far as I know, have never bumped the rev limiter (I’m not sure I’ve ever seen anything over 6,000 on the tach) and I’ve not had any mis-shifts. Yet at hour 631 each of the ranges 1, 2, 3, 4 and 5 (according to my Durametric readings) incremented by 1 ignition – is that even possible across such a broad range of RPM’s for the ranges? Also at 705 hours, ranges 1 and 2 incremented by 5 ignitions, ranges 3 and 4 by 3 ignitions and range 5 by 1 ignition – again no rev limiter or mis-shift occurrences. Any guesses as to what is going on. I’m at 22,600 miles and 750 hours and still running great. I may just have to stop doing these DME readings.

 

Hmmmm, that is a little strange. A couple things to keep in mind though. To get range 4, you have to go past 1,2,3. To get a 3, you have to go past 1 and 2....so some of your increases make sense. The others are a bit confusing.

But I'll say this...try not to obsess over it! The more you count them and try to analyze what's happening, the crazier you will be. If you don't miss downshifts, and upshift when you're supposed to, you'll have nothing to worry about. Over-revs are not an indication of any future failures, but more a tool to determine why a past failure occurred (mostly by the dealer in a warranty situation).

 

Thanks for the info - I pledge to stop obsessing over this...but if 3 ignitions occur every revolution how can only 1 ignition be recorded in a third of a revolution from 6,800 rpms to 7,900 rpms (the ranges 1 through 5 thresholds)?

 

That is a bit confusing but keep one thing in mind. The counter refers to ignition not how many times you actually over-revved the car. So for example, you can miss one downshift and accumulate 100 on the counter. So for the count to only go up by 1 is definitely strange. Without having the car here and scanning with the PIWIS it's hard to say. I'm not sure if Durametric is reading the info in the same way, or as detailed, as the PIWIS.

 

Good point...and thanks again. I did ask Durametric tech support about this months ago and never received a response. If I ever have an opportunity to get a PIWIS reading, I'll compare the two.

 

I am pretty sure i ve posted these data again somewhere...
997TT
Range 1 - 6800-7000
Range 2 - 7000-7200
Range 3 - 7200-7400
Range 4 - 7400-7900
Range 5 - 7900-9000
Range 6 - 9000 up

these overrev ranges cant be modified...they are always there...

 

You are exactly correct. Here's the TSB:

 

I like the "good old days" - only two ranges in the 996. Were there any ranges pre-996?

 

Many tunes in which are custom or have the installation in this category of different turbos such as 30/76 or others increase the rev limit.... This is done by Protomotive, Softronic, Switzer, Vivid and many others. The revs would most likely be increased for tips to 7200. The over revs would only occur if the limiter was hit and not until then. This also is done to cars that as a tip had the TCU upgraded to shift higher. The higher shifting requires the DME rev limit to be raised for it to work.


Most owners understand that have installed these kits and flashed the cars etc would not worry about range 1-2 or 3.


Now should a man trans car get the RPM raised it would not get over revs until the raised rpm was hit also. The rev limiter is the start counter.
So raising the rev limit accordingly in the cars would only show up to a 3 in NA cars and generally 2 in TT cars. The 3 in the NA cars can happen even w/O a tune raised or not.

This is also done for track cars as it offers the drivers the capability to extend a gear and not require a shift at times. Raising the limit also never comes into play unless you hit it.

I believe this has been gone over many times already.

 

I have a few 1 and 2s, but what's strange is the hours. The total operating hours reads 134.3 but the overrevs are recorded at 640 h. What this means is that my tune travels faster than the speed of light and I'm reversing in time.

There is definitely something glitchy about the durametric/flashing and as other's said, need to check it with PIWIS to be certain.

 

The ignitions are 3 per rotation yet the binary is working on a deviation of 4.

 

TTdude...I ve seen several dyrametric readouts that wont make sense...PIWIS is the right tool to have the proper icon of your overrevs/engine hours...However try to download latest version of dyrametric and read the revs again...
Scott...based on your post,assuming we have a manual 997TT and i ask you to raise rev limit to 9000rpm,if i change before 9000rpm and not hit rev limiter,i wont see overrevs?is that the case?

 

Thanks will do. I'm curious to hear the answer to your question to Scott too.

 

Yes that is correct when done properly.

Just as a heads up the lack of over revs in a PIWIS tester or having none would show as a line -. When they do occur they would be listed as the number with the hours of occurrence such as Range 1 120/232H etc. , none would read Range 1 -.

Over revs can also be erased or added with the proper knowledge just as programming operations and IPAS data pulled from DME's. The pulling of the IPAS data and resetting the programming operations is mainly done for Dealers. This is when they entered the wrong data while trying to program a car and do not know what they entered, such as a Imob code. The resetting would be if the DME had been programmed 3 times by the dealer and then required a 4th to a factory file. They would normally in the past not use the DME and have to use another starting at 0.

 

Anytime! In the olden days (back when I was young, green and gullible with other software the tuner would tell me that raising the rev limiter when done "right" (don't make me laugh!) would have no ill effects as the point were simply "adjusted" higher. First time I used a PST2 (which I still have in its lovely 386 form) in 2005 I was quite shocked to see the results. Some of the code is so broken in the attempt to "mask" the over revs that I've seen cars with 50,000 type V's with only 9,000 miles on the ODO That'd be a lot of mis-shifting eh? And yes we've had to re-do a few other and old tunes over the years and that same sort of stuff shows up. There are all sorts of interesting things to be seen where you can see a tuner has "guessed" but done so incorrectly. They've raised fuel tables where they should have lowered them vs factory. I remember Todd@EVOMS showing me a messed up Cayman one where at super low rpms and start the fueling was raised way over stock and up top was cut down way below stock instead of visa versa. Another table was just blasted entirely with 10% more "everything/everywhere".... I've seen cars with stock rev limiters show the very same sort of over revs with crazy throttle increases etc...

But those are at the old days... The nice thing with the software we use now is that we specify what we want and how we want it and have full disclosure and control. Instead of revving higher needlessly we focus on cool things like enabling left-foot braking and the like...