Rev limiter and the PDK

[FrancisA]

Hi All
Quick educational question. I have a 991.1 C2s. If you are in automatic mode and you downshift with paddle, will the PDK automatically upshift when you hit the limiter or do you have to upshift yourself? I don’t want to try it and find out I have over revved.

Cheers All for the feedback

[jackwood]

Yes it will.

You can’t overrev a PDK box. The software will protect you from doing anything to damage the box.

[IMI A]

Thats not true according to OPC Hatfield? They reckon we over revved their 991 turbo s demo car when on loan always driven in D.

[BAMoFo]

If it is possible to over rev a PDK box on a downshift it is a design flaw and one that seems too obvious to miss.

[foresterlad]

Yes agreed downshifting will exceed 7500 rpm
with PDK and is a real risk using paddles on a track day
which is why I leave the box to make decisions
In any case the instructor on my GT experience day
told me the car is better at cog changing than you

[jackwood]

In the case the OP is talking about, he’s in D, pulls the paddle to downshift, then runs up to the limiter, the car will change back up again as he approaches the limiter.

At the very worst it will bounce off the limiter. But it won’t overrev.

I’m sure there is a document from Porsche advising OPC techs to ignore any overrevs on a PDK car Rev report.

It definitely shouldn’t/doesn’t allow a downshift if that downshift would put the engine revs over the engine limiter value.

[130R]

BAMoFo said:

If it is possible to over rev a PDK box on a downshift it is a design flaw and one that seems too obvious to miss.

This. You can't over rev an automatic ..

[foresterlad]

You can register over rev on the ECU in band one
7500/7700 in some situations when the engine is bounced on the limiter in manual mode.I guess it depends on what you’re
defining as over rev.

[gtsralph]

130R said:

BAMoFo said:

If it is possible to over rev a PDK box on a downshift it is a design flaw and one that seems too obvious to miss.

This. You can't over rev an automatic ..

You can over rev PDK. I bought a 991.2 PDK GT3 and was assured by the OPC salesman that it was not possible, contrary to my experience with PDK cars. I got the full pre-sale ECU report printout (it runs to 40 odd pages) and there were Range 1 over revs, not a lot but more than attributable to measurement errors.

The sensor runs off a toothed wheel and is subject to signal errors so not entirely accurate at the margin.

It can over rev, extreme example going over a hump back bridge full throttle and breaking traction whether in auto or manual, the electronics can’t shut off power fast enough.

I’d always get as a minimum an over-rev report on a used Porsche.

[130R]

gtsralph said:

130R said:

BAMoFo said:

If it is possible to over rev a PDK box on a downshift it is a design flaw and one that seems too obvious to miss.

This. You can't over rev an automatic ..

You can over rev PDK. I bought a 991.2 PDK GT3 and was assured by the OPC salesman that it was not possible, contrary to my experience with PDK cars. I got the full pre-sale ECU report printout (it runs to 40 odd pages) and there were Range 1 over revs, not a lot but more than attributable to measurement errors.

The sensor runs off a toothed wheel and is subject to signal errors so not entirely accurate at the margin.

It can over rev, extreme example going over a hump back bridge full throttle and breaking traction whether in auto or manual, the electronics can’t shut off power fast enough.

I’d always get as a minimum an over-rev report on a used Porsche.

Range 1 on a report is caused by hitting the rev limiter which is irrelevant. You can't over rev an automatic which is why any over rev report for a PDK car is disregarded by Porsche for warranty.

[Armitage.Shanks]

911 Virgin have a piece on their website about over revs. They mention PDK to say it’s ‘possible’ and something to do with the wheel rotation speed v engine revs like going downhill at the point of being on the limiter?

[foresterlad]

For all practical purposes and certainly extended
warranty PDK cars aren’t at risk. The original question
was can the rev limit be exceeded and it can register in
range one

[Armitage.Shanks]

foresterlad said:

For all practical purposes and certainly extended
warranty PDK cars aren’t at risk. The original question
was can the rev limit be exceeded and it can register in
range one

Not just Range 1 it would appear:

https://911virgin.com/engine-revs/

[saveloy]

This has been documented. Travelling downhill, holding a gear, whilst on the rev limiter will push the engine over it, mechanically.

[jackwood]

That must have to be a steep old hill…

Pretty extreme and rare circumstances required though. You’d have to be so unlucky to hit that combination.