Cayman S, Computer tracks owner's behavior for preowned certificat

[farmboy]

Fellow Porsche people,

I'm looking around for a second Porsche. Specifically a pre-loved Cayman S. One of the dealers I visited mentioned that during the used car inspection they check "that the previous owner hasn't exceeded the redline more than three times". I have no doubt that the Porsche diagnostic tool/computer can read that kind of information out from the engine computer... but this seems strange on so many levels. Can anyone confirm that the PST2 (diagnostic tool) can really read out such things? Is there also tracking on max GForces I wonder? Do dealers really inspect these sorts of things before certifying a used car?

Thanks

Jeff

[Nick_USA]

Fellow Porsche people,

I'm looking around for a second Porsche. Specifically a pre-loved Cayman S. One of the dealers I visited mentioned that during the used car inspection they check "that the previous owner hasn't exceeded the redline more than three times". I have no doubt that the Porsche diagnostic tool/computer can read that kind of information out from the engine computer... but this seems strange on so many levels. Can anyone confirm that the PST2 (diagnostic tool) can really read out such things? Is there also tracking on max GForces I wonder? Do dealers really inspect these sorts of things before certifying a used car?

Thanks

Jeff

The PIWIS can be used to verify engine use ie over-revs. For the 987 there are 6 ranges:

1 - RPM Achieved 7300 to 7500

2 - RPM Achieved 7500 to 7700

3 - RPM Achieved 7700 to 7900

4 - RPM Achieved 7900 to 8400

5 - RPM Achieved 8400 to 9500

6 - RPM Achieved 9500 to 11000

Ranges 1-3 are generally overlooked by the dealer and 1-2 can easily be hit with hard acceleration and hitting the 'rev limiter'

Ranges 4-6 are generally hit by incorrect down shifting most common going from a high revved 5 down to 2 instead of 4 etc. These are not generally liked by the dealer and could indicate abuse. 6 being the worst and this occurs when the engine hits the mechanical rev limiter btw.

Edited August 10, 2008 by Nick_USA

[donlycan]

I never knew there was more than 1 rev limiter. How could a 987 rev to 10 grand from a missed down shift??? Wouldn't the regular rev limiter kick in?

donlycan

[Loren]

I never knew there was more than 1 rev limiter. How could a 987 rev to 10 grand from a missed down shift??? Wouldn't the regular rev limiter kick in?

donlycan

The is only one rev limiter.

These are DME reports of revs - they are called "stages".

The engine rev limiter can do nothing for a missed downshift or a spin (backwards) where you fail to get the clutch in fast enough. Both can seriously damage an engine.

[stef]

I never knew there was more than 1 rev limiter. How could a 987 rev to 10 grand from a missed down shift??? Wouldn't the regular rev limiter kick in?

donlycan

The rev limited doesn't actually "limit" the revolutions. It cuts power when accelerating past the limit.

If you downshift, instead of the engine applying power to turn the wheels, the wheels are applying power (from forward inertia) to the engine. If you're going 80 and downshift from 5th to 4th, the revs will go from about 3000 to about 4000. But if you "miss a downshift" and instead hit 2nd gear at 80mph, you'll spin the engine around 8000 rpm (and probably crap your pants from the engine screaming its disgust at your driving skill).

[Nick_USA]

How could a 987 rev to 10 grand from a missed down shift???

donlycan

Try changing down from 6 and hitting 1 instead of 5 or 3. OK pretty dam difficult, more likely changing down from 5 to 4 and hitting 2.

Edited August 13, 2008 by Nick_USA

[simmons]

I'm looking around for a second Porsche. Specifically a pre-loved Cayman S. One of the dealers I visited mentioned that during the used car inspection they check "that the previous owner hasn't exceeded the redline more than three times".

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simmons

Edited August 28, 2008 by Loren
removed commercial signature