Reading through some of the posts regarding buying a used TT, a number of them suggest getting the car checked during the PPI for Type II over revs. Can someone please explain exactly what that means?
Also, should you avoid a car that has had even one of them?

Again, thanks on advance for all the help.

Ronan

 

A type 1 over rev occurs when you linger on the throttle a bit too long when making an upshift. The rev limiter will prevent any damage at this point, but the event is recorded as a type 1 (actually, each "event" will show dozens or hundreds of counts).

A type 2 over rev occurs when you are shifting, say 4th to 5th, but accidently grab 3rd instead. At this point, the engine is forced by the wheels to rev higher than its design limits, and serious damage can occur... like pistons running into valves, or connecting rods being stretched. Even a single type 2 over rev is bad, and often a dealer will deny warranty coverage to an engine that has recorded a type 2 event.

 

ca993twin
and often a dealer will deny warranty coverage to an engine that has recorded a type 2 event.

He is absolutly correct with any over revs in range 2, also known as mechanical over rev, Porsche will do little if nothing to assist in the claim. The funny part is range 2 problems might not even seem evident unless you do a leakdown test, thats what i have seen. You might not even notice a difference in the car, it maybe only a little rougher at idle (which is usually slight damage to the valves not seating properly anymore due to light piston contact). On the flip side spend enough time in mechanical over rev and it can grenade an engine.

 

type 1 has fuel cut off anyway so I don't see it as a problem

 

I am a lurker and currently on the market for a 996tt, I am curious about this one..

Can't someone just edit these out of the computer before they brought the car in for service or put their car up for sale? Also, does a PPI normally include a leak down test? I was under the impression that getting the plugs out was quite a battle.

Thanks in advance, Blair

 

Nice answer you old fart!!!

 

So bottom line I assume that you are saying that I should not buy a car that has any Type II's recorded?
What about Type I's they seem less serious?

 

That would be nice ..but almost all these cars will have atleast one or two type II overrevs.
JMO

 

Not unless they miss a shift like someone already stated, range 1 over revs are redline and are ok, I would be weary of range 2 even at a small number. However, you will have to get a feel for the car to, if there are range2 get a leakdown and compression check before purchase. Unfortuntatly there is now way to erase those rev counters they are stored in the DME

 

Not easily with factory supplied tools/equipment, at least not without intimate design knowledge (procssor memory map) of the ECU. Parameters such as these are designed to be 'permanent'.
It can be done, but it's not quite as easy as clearing a 'Check Engine Light"

Depends on whether or not you ask/pay for one.

If you remove the rear bumper, they are easier to get at. Spark plug removal threads have detailed this before

 

Will the date/time of the event be recorded? I never knew about Type II (or type 1) over revs when I bought my '02 TT...I've been very careful with my car, but it's off warranty now (though it's CPO'd)...

There really isn't anything I can do about it now, but I've never driven a 996 Turbo other than my own. I've driven my car 27k miles since I bought it...so these days I know what it feels like and I'd be able to tell the difference if I drove a different 996 TT.

I'd really like to know if my car had any of these - and when...and ultimately, if they were done before I bought the car...and it was CPO'd...is it Porsche NA (and the dealer's) responsibility to honor warranty work?

 

Yes there is a time hour stamp. There is no date stamp.

Don't lose sleep over it, if your car is running and not missing it's fine.. It it really bothers you, take it in to the shop and replace your plugs and do a leak down test. If you miss a shift, you will know when you stuff the valves into the piston.

 

Hey all,

I really wanted to buy this car until I got these results:

2001 Turbo with 15k miles, carbon fiber, power, full leather, etc.

533 total hours
12175 range 1 at 524.8 hrs . .. ( I know this one's not so critical)
932 range 2 at 498.8 hrs

Would a leak down confirm everything's okay or is there just too many things that could be damaged?

Thanks,

Sean

 

932....is that the number of actual revs that took place above the redline?? I don't think that meant the previous owner has committed Type 2 over revs 932 times....The car would be trashed by now.

If it is the total number of actual revs, which I think is the way they are recorded and presented, and let's just assume that the overrev took the rev above redline of 6600/min to a top rev of 8600/min, 932 revs over the redline peaking at 8600/min and back down would roughly equal 7 seconds of revving above redline.

I think the 498.8 hours is a time point, meaning the over rev event took place when the engine was 498.8 hours old.

It's still good idea to do compression or leakdown, especially on an 2001 car. It's a few hundred bucks that can give you more security paying out tens of thousands of bucks.

 

I think it's the number of ignition firings which if you do the math doesn't seem like much, but I was told that Porche will void warranties for just 5 because of the possible mechanical damage . . . I think I had like 150-200 on my 996 when they gave me grief.

Seems like plenty of guys have bought cars with no or very few range 2's but is it really hard to find a car that old with no range 2's? I also now have conflicting info as to what a range 2 over rev is . . .

Another mechanic told me he regularly sees 200 range 2's so ?????

Thanks,

Sean