+1^ compression and leak down test is key

 

Type 2's can be significant in this engine especially for GT3's. Dealers have denied warranty covereage for type 2 revs. Even though the car only has less than 10k miles the dump of the ECU should tell at what hours (engine hours) the type 2 ocurred. If they occurred in the last week, it would possibly be more significant than if they occurred 5 years ago. Type 1 revs are throttle inputs that reach the rev limiter. These are not a big deal at all. Type 2's can be money shifts or they can be agressive (forced) down shifts while the engine is past the rev limiter. The 04 Turbo I just bought has 15 type 2's. That is not many.

On the 364 type 2's that is not many either. If they occurred long ago a compression and/or leakdown might identify any problems (if the tests are done correctly). If they happened recently a leakdown or compression test might not reveal the damage.

I would be concerned about other items such as seals, water pumps, air conditioner condensors with as few miles as it has.

 

Correct, but it does tell if the car was beat or not. It may not be a go no-go based one these ever revs being there, but it can be an indication based on the number of over revs. Ideally a valve piston contact scenario would show itself and be pretty evident. But the other possible things that can be damaged by over revs do not show themselves until it is too late.

The fairly common damaging things that happen during an over rev are valve piston contact caused by valve float, excessive oil heat that causes coking of oil, excessive rod and timing chain stress as well as oil starvation to bearings. The maximum RPM an engine can run is a variable based on how well the rotating assembly is balanced and the capabilities of the valvetrain. In the end your comfort levels are more important when buying a car with known situations like this and you should consider the cost to repair said possibilities. It isn't a guarentee that the engine is going to explode if the engine is over revved, but it should be a consideration. I am no expert on these things, but when the risk is 20k engine I would pay more attention to it than on your typical camry.

 

Or the stage 2's could be an extended rev limit tune, simply hitting the extended rev limit will log type 2 under this condition.

Like many have said, compression or leakdown test with PPI on a car if there is a concern re: over-revs.

Some are pretty fanatical about over-revs, part of the reason has to relate to the factory position to use this as a tool to deny warranty coverage in the past.

 

Anyone have any links or first/second/third hand accounts of motor or trans failure related to over reving these cars?

 

Their was a case on Rennlist of a crank failure and the ECU showed excessive type II over revs. The only problem is that when these engines come apart it is often times difficult to determine the cause because usually hardware is the only remaining un-damaged part.

I am not trying to scare you. The 996TT engine is not a bed of fragile egg shells, but don't ignore your overrevs. Talk to a trusted porsche shop and get an idea of what is good and what isn't. Don't reject any car with over revs, but compare them and use them as a sign of use and abuse. In the end it may be a good bargaining tool.

 

I know, you are going to tell me damage can happen in a fraction of second but. Let's do the math.

On a four stroke engine you got a spark every 2 revolution of crankshaft. Means 6 cylinders = 3 spark per revolution of crankshaft , So 364 divided by 3= 121.33333.... So we had 121.3 revolution of crankshaft over 6750 RPM. So if I got 6750 revolution in one minute that means 112.5 revolution in one second ! Do you agree with me while I am thinking loud ;-) If not please don't hesitate to correct me. But because we are in overev situation , may be 6800 or worst 7000! This condition last less than 1 sec. Ouch I need a break....

I forgot to mention. Type 1 and type 2 over revs add up to each other. In this "type 1" case you had 7830. May be it happen 10 times!!! Same thing for the type 2.....

 

My head hurts after reading this.

 

That's only about 0.6 seconds in the Type 2 range. It could be that the car was flashed and has a raised rev limiter which would make it easy (or easier) to record Type 2s......

 

I got tired of reading after page one, sorry if someone on page 2 said this already, and I am going to repeat what has already been said, but clarify from my own perspective. If the car has some sort of aftermarket flash and the limiter has been raised, the type 2s are pretty much harmless, I try not to bang my limiter, but when I do I get a type 2, oops, both my type 1 and 2s are maxed out, meaning the counters dont even read anymore, they just update when the last one was. Its a fun game I play with myself, see how long I can go without banging it...anyways, at that low mileage, the car you are looking at very well might not be modded with a flash, as others have said, see when the last type 2 was. If it was recent, then I would be more skeptical, if it was months +, I would not put much stress on it. Either way though, I would have a compression test done and have a shop take a look at it and have them give you their opinion on the state of the motor based on its mechanical well being, not what the computer says about over revs. EFF DAT SHI BRAH!

...Ok I just looked at the car, its great, that interior color could be hard to live with though, you can probably negotiate 5k off the top just for that, talk to legendr34...

 

Do what is comfortable. I can tell you that there are people on this board who run 7600RPM redlines in their tune. The likelihod of the engine being hurt in less than a second iof total type2s is VERY low.

Your money, your car of course.

 

Is this your first Turbo Porsche purchase? 364 Type 2 over revs does not mean it was "money shifted" 364 times. The number is based on the number over revs per cylinder per rpm. A few hard downshifts could have caused most of these. You should worry more about second gear pop out issues if you think "money shifts" are a problem. (A more interesting question is how did you "moneyshift" at a drag strip since all those should of been upshift type 1 overrevs.) If you're going to modify this motor quite heavily (north of 600HP) than you must be considering upgrading the internals (rod, crank, pistons, etc). In this case if there is any prior internal stress, you're going to replace these parts anyway. An observation is although these cars perform quite well at the drags, they are not built for it from the factory. My last observation is the price on this car is very fair.

 

There is a fundamental disconnect here with the dicsussions of flashes:

Just becuase ONE car can collect Type 2s due to a flash with an altered redline does not tell you a thing about the Type2s that were collected on the OPs car!

As we all know it COULD have been a money shift. All the rationalizations in the world will not clarify the cause. Nor will it tell you the peak RPM that lead to the type 2.

 

Correct, I think most are saying, have the car looked at by a qualified mechanic, have them do a compression test or leakdown test, especially if the type 2's are more recent and things aren't checking out.

If you like the car, and everything checks out, then why pass on it ?

Is it safe to say that extended rev limit cars are all rubbish ? I've never missed a shift, but I like to rev the car up from time to time = type 2's, enjoy life, enjoy your car, take care of it. Why buy a turbo and granny shift all the time ?

 

I dont quite understand why powershifting a car has anything to do with hurting the motor. If you stay within the redline it shouldn't hurt it. Porsche or any competent tuner leaves some cushion for where the car will get hurt and where the redline/fuel cut is. Now forcing the car mechanically over the rev limiter is a different story like shifting from 3 to 2 instead of 3 to 4.