Hi,

I'm trying to get more detail on the interpretation of the computer readout for an 01 996 TT that I'm interested in buying.

Here's the data:

The total hours on the car is: 1284
Number of ignitions, range 1
53689 1275h

Number of ignitions, range 2
453 1253h

Regarding the Range 1 over-revs, it's hitting the rev-limiter which is no big deal, but number of ignitions is 53,689.

Does that mean over 2 1/2 minutes of red-lining?

I'm thinking that if there are 3 ignitions per revolution. 53,689/3 is about 18,000 revolutions of redlining. Let's say the rev-limiter hits at about 7,500 rpm.

I'm thinking whenever I've hit the rev limiter on the track as I've had over 100 track days, mostly on motorcycles, but even in a car, I may hit the rev-limiter every once in a while for a moment or so.

So does that mean that probably someone abused this car to the max by hitting the rev limiter 100's of times?

Thanks in advance for anyone that can shed some light on this for me!

 

Same as everyone said over on Rennlist!



Stock rev limit is not 7500..>As I reall there are some programs that raise the rev limit (So the ignitions will allow it to rev and not cut the ignition) but the DME still 'traps' these excursions as over-revs

Lets see what the crowd over here says...

Oh, and get their opinion on the Upsolute flash...

A

 

That is normal if the car has a tune, so I've read a few dozen times.

 

Stage 1 on a stock 996tt are ignitions in the range of 6750 and roughly 7250rpm.
Stage 2 on a stock 996tt are ignitions in excess of 7250rpm even though some may argue that its closer over 7000rpm.


For each rotation of the crankshaft, there are 3 ignitions on our cars. At 7250rpm, there are 21750 ignitions per minute or 362.5 per second. Simple arithmetic will allow you do determine how long your engine has spent in the overrev range.

In your example above, 53689 range 1s equals 2minutes 28 seconds.
In your example above, 453 range 2s equals 1.25 seconds.

For a street driven car with 1284 hours you should have roughly about 39K miles on the odometer. If it spent a lot of time on the track the miles would be quite a bit more. My car which has no track time is right at a 1000 hours and 29k miles, or 29 mph average. Recently I saw a 996tt with 500 hours on it and 24k miles which works out to 48 mph. It was a car with a lot of track miles....

If your car is chipped than it usually has the redline raised. As a result, if you rev to the new redline you will record stage 1 ignitions every time and if you hit the new higher rev limiter (assuming 7000 - 7250rpm) or go slightly beyond it you will record stage 2 ignitions.

Hope that helps

 

Good post, agree with most.

One comment on this: You cannot determine how LONG the engine has been in overrev range since you don't know which RPM he hit.

Is it 453 type 2s generated at 7500 rpm (20 milliseconds);

or 453 generated at 11,000 rpm (13.7 milliseconds)

Just saying...

A


PS Of course if it really were 11,000 we'd probably not be having this discussion)

 

If we are splitting hairs than yes. I'm not sure the engine could accelerate to 11,000 in 13 milliseconds not to mention that it would self destruct around 8 or 9k.... The above numbers are in the ballpark though.....

 

So there sounds like maybe one downshift mis-shift for a split second for the Type 2 over-rev.

My concern is that if the engine has experienced about 2 minutes, 28 seconds of Type 1 over-revs, does that seem like a lot of time up there?

 

If your rev limit is raised then there might not have been a missed downshift. My car has about 20000 type 1s and 2700 type 2s WITHOUT a missed shift but with a rev limit raised by 500rpm...

 

Thanks, I've decided to pull the trigger on this one. Hopefully it will turn out ok. Here's the car sans the wing, seats, roll bar and carbon mirrors.

https://www.6speedonline.com/forums/a...ic-silver.html