NewYorkBuck

I just performed a 15,000 mile service at Power Tech in NJ on my 2004. Just for fun, I had them check for overrevs on the engine.

Well, while they didnt provide firings like you gents typically show, they simply wrote on the bill - "RPM limits recorded as #1 (7300-7500) at 128.6 hours (before I owned the car) and #2 (7500-7700) at 478.0 hours.

This is the kicker - the car currently has 478.8 hours, and the last person to drive it was (grrrrr) my brother. My questions are as follows -

1 - Are these both type 2? Again, I cannot tell the way they presented it.

2 - Will this void my warranty?

3 - He swears he didnt miss a shift - but he did admit to accelerating very hard in first gear. Could this have brought the revs to that high of a level (7500-7700)? Although his Porsche driving privileges have now been revoked, I would like to know if what he claims is possible.

Thx in advance.

ltc

Can't tell from the descriptions. Easy enough to bring the car back, plug in PIWIS or PST2 and get Type1 and Type 2 read outs...along with anything else you're interested in.

Type 1's should NOT void a warranty, unless there are "too many" of them, indicative of "implied track use".
The (up)rev limiter is there to simply protect the engine, no problem.
Type 2's tend to get less lenient treatment.

It looks like your brother simply didn't expect the car to hit the rev limiter so fast in 1st.

NewYorkBuck

Wow ltc - thx for the fast response. I guess part of my question is - since the redline is 6600 - is is possible to have a type 1 at 7700 rpms? Does seem like a lot of inertia to spin it that high even w the clutch depressed.

ltc

it depends on if the car is stock or not.
you can record an instantaneous higher RPM past the rev limiter (again due to mechanical inertia vs cutting spark/fuel) for a brief moment.
again, I wouldn't worry until you had a second readout....it takes 5 minutes to do.

Kevin

The question that I have is.. Did he miss a shift.

Was in 5th and stuff it into 2nd gear?? Because that is what the data is showing..

NewYorkBuck

He claims he did not. Also, the car is completely stock. FWIW - it seems to be running fine.

Kevin

ltc is correct, plug in a PIWIS or PST2 and see the results for yourself on the screen with your own eyes.

Chuck Jones

Wow...a 7700 rpm event on an upshift caused by "inertia"? That seems a bit over the top for me. I'll bet your brother was panic stricken when whatever-it-was happened....the hours on the readout suggest this was a rather recent event?

NewYorkBuck

Very recent - less than two hours of running time ago. When I picked up the car - he was with me. His faced looked a little shocked when he saw the results.

I guess I'll have to get the readout like ltc and kevin suggested. The only thing is - when I asked Mike at PTech if they were type 1 or type 2 - he said - "Well, RPM breaches happen in stages - the higher the RPM, the higher the stage." This really didnt answer my question, but he is rumored by many to know what he's doing, so I was a little surprised at his answer.

Anyone know a place in Northern NJ that will give the the detailed readout?

Edit - also - it was 7500-7700 RPM, so not sure exactly where it happened. But again, the reason Im wondering is that does seem like a lot of inertia.

ltc

OK, picture this.
You are in 1st gear, right foot flat to the floor (fuel and spark present), engine is spinning up towards redline and you then (for whatever reason) push in the clutch......rotating mass decreases suddenly while the engine is still under fuel/spark and (mechanically) accelerating..
What happens?

Of course it's easier to envision a mechanically derived overrev (Type 2) as Kevin said (the classic 5-2), but you can get past the rev limiter on the way up as well......infrequent, but it canhappen.

Again, PST2/PIWIS will tell you everything you need to know....or more than you care to know

NewYorkBuck

Your first paragraph is exactly what he described.

Kevin

Maybe I don't understand the angle here or what I am missing..

This is a Type 2 overRev if the numbers that you have reported are correct.

IF your ENGINE went to 7499 that is tough on the valve-train!!! If your engine went to 7700 THAT IS REALLY Tough on your engine RODs>> ouch.. You can stretch your rods and float your valves.

ltc and myself were asking you to RE-check the values because they might be in error. However, if they are in fact true. I would be having a serious talk with your brother.

Kevin

To answer your last statement, you aren't going to get REV's in 7500 to 7700 with a overRev in first gear. Because there is a factory RPM limiter at 6750.. He is going to be bouncing off the limiter. You will over-run it maybe by 50 to 60 RPM's but not 800 RPM's.

Edit>> My above statement is based on someone trying to or attempting to shift.. However, if someone is careless, and keeps the pedal glued to the floor while hitting the REV limiter typically a 250- 350 RPM incident can occur. 800 to 1000 RPM's over is a stretch for me in first gear.

Chuck Jones

That's exactly why I won't let my brother drive my car unless I'm in it with him...in spite of the begging and attempts at bribery with promises of cases of Corona....it's just too much of a temptation for someone who has never had a Porsche and always wanted to drive one....to push it to the limits....to feel the rush that his F 250 pickup just can't begin to give him. There's never any malice intended....just too damn much temptation. But the bottom line is ....who pays the bill on this? You do of course.

NewYorkBuck

True. Its probably safe to say that his days driving my car are officially over......