[fpena944]

This might be a stupid question but it just came to me as I was driving earlier this evening.

So when you have a manual transmission the engine changes it's RPM range during each shift over the course of 1-2 seconds or so. This "seems" like enough time for the engine to adjust to the new speed without shocking the cylinders and valves.

But with a PDK this whole transition from one gear to another takes place in milliseconds. So in my mind it appears that going from 2k RPM to 4k RPM during a downshift in a few milliseconds would put a tremendous strain on the components of the engine.

Am I overthinking this and it's not really an issue? Or is there a slight increase in stress on the engine with this faster transmission?

[sh944]

Overthinking it…. I’d suspect the PDK actually puts less stress on the engine, not more, since it’s more in sync with the engine than a manual shift would be.

[fpena944]

Overthinking it…. I’d suspect the PDK actually puts less stress on the engine, not more, since it’s more in sync with the engine than a manual shift would be.

But with the manual transmission the engine has more of an opportunity to "ease" into whatever RPM range it's going into. That's why I was thinking it actually puts more strain on the engine.

I mean I do realize that this thing is going up to 8k RPM so the differences between gears isn't really all that substantial but it does seem like there would be some impact.

Unfortunately was thinking about it again on my drive this morning!

[N_Jay]

This might be a stupid question but it just came to me as I was driving earlier this evening.

So when you have a manual transmission the engine changes it's RPM range during each shift over the course of 1-2 seconds or so. . . . . .

(In my best voice from "The Sand Lot") "You shift like a girl!"

[fpena944]

This might be a stupid question but it just came to me as I was driving earlier this evening.

So when you have a manual transmission the engine changes it's RPM range during each shift over the course of 1-2 seconds or so. . . . . .

(In my best voice from "The Sand Lot") "You shift like a girl!"

Hey you know replacing a clutch or a synchro is no fun!

[worf]

@N_Jay is technically correct: You need to “relearn” how to shift if indeed your are “dragging” the engine speed with the clutch as would seem to be the case from what you wrote.

The best shifting with a manual is done by “matching revs” before engaging the clutch, where “engaging” means releasing the clutch pedal. The easiest place to start is by googling “double clutching.” Once you’ve got the gist and practiced a little you can dispense with the “double” part; the “double” is simply a mechanism to make you think about each step and “slow down” the shifting while you practice and learn and train the muscle memory.

Come back here for further explanation or questions once you’ve done your homework

As for PDK, the DME automatically matches revs for shifts.

PDK does the better than all the other “automatic manual” transmissions. Audi/VW DSG in particular(*) “drags” the engine when it shifts. Many folks can’t “feel” it because they’ve never experienced a proper rev-matched shift.

(*) And thus “PDK” in the Macan because it’s really a Q5 box not actually Porsche PDK.

[fpena944]

@N_Jay is technically correct: You need to “relearn” how to shift if indeed your are “dragging” the engine speed with the clutch as would seem to be the case from what you wrote.

The best shifting with a manual is done by “matching revs” before engaging the clutch, where “engaging” means releasing the clutch pedal. The easiest place to start is by googling “double clutching.” Once you’ve got the gist and practiced a little you can dispense with the “double” part; the “double” is simply a mechanism to make you think about each step and “slow down” the shifting while you practice and learn and train the muscle memory.

Come back here for further explanation or questions once you’ve done your homework

As for PDK, the DME automatically matches revs for shifts.

PDK does the better than all the other “automatic manual” transmissions. Audi/VW DSG in particular(*) “drags” the engine when it shifts. Many folks can’t “feel” it because they’ve never experienced a proper rev-matched shift.

(*) And thus “PDK” in the Macan because it’s really a Q5 box not actually Porsche PDK.

I'm probably not describing what I mean properly.

What I meant by the 1-2 second shift was the elapsed time between pushing the clutch in and going through the process where the car is fully in gear again. I'm probably overestimating this time but it's substantially slower than what the PDK can do.

I do rev matching while downshifting so familiar with what you're saying, but what I'm talking about really doesn't have anything to do with the shifting itself. It's the speed of how quickly the engine itself has to change from, let's say, 2k to 4k RPM. That's where I have the question.

On a manual transmission car this change in RPM doesn't happen in an "instant" like it does on a PDK. So if you were to observe the RPM gauge on a PDK, it would go over that 2k RPM range in milliseconds. But in a manual it's over a slightly longer period of time which in my mind would be less of a shock to the internals.

Again I'm likely doing an awful job explaining what's in my head but the rate of change is what I'm really inquiring about.

[N_Jay]

@N_Jay is technically correct: You need to “relearn” how to shift if indeed your are “dragging” the engine speed with the clutch as would seem to be the case from what you wrote.

The best shifting with a manual is done by “matching revs” before engaging the clutch, where “engaging” means releasing the clutch pedal. The easiest place to start is by googling “double clutching.” Once you’ve got the gist and practiced a little you can dispense with the “double” part; the “double” is simply a mechanism to make you think about each step and “slow down” the shifting while you practice and learn and train the muscle memory.

Come back here for further explanation or questions once you’ve done your homework

As for PDK, the DME automatically matches revs for shifts.

PDK does the better than all the other “automatic manual” transmissions. Audi/VW DSG in particular(*) “drags” the engine when it shifts. Many folks can’t “feel” it because they’ve never experienced a proper rev-matched shift.

(*) And thus “PDK” in the Macan because it’s really a Q5 box not actually Porsche PDK.

I'm probably not describing what I mean properly.

What I meant by the 1-2 second shift was the elapsed time between pushing the clutch in and going through the process where the car is fully in gear again. I'm probably overestimating this time but it's substantially slower than what the PDK can do.

I do rev matching while downshifting so familiar with what you're saying, but what I'm talking about really doesn't have anything to do with the shifting itself. It's the speed of how quickly the engine itself has to change from, let's say, 2k to 4k RPM. That's where I have the question.

On a manual transmission car this change in RPM doesn't happen in an "instant" like it does on a PDK. So if you were to observe the RPM gauge on a PDK, it would go over that 2k RPM range in milliseconds. But in a manual it's over a slightly longer period of time which in my mind would be less of a shock to the internals.

Again I'm likely doing an awful job explaining what's in my head but the rate of change is what I'm really inquiring about.

THAT is what I meant? 1 to 2 seconds, what are you doing, . . . your nails?

[fpena944]

@N_Jay is technically correct: You need to “relearn” how to shift if indeed your are “dragging” the engine speed with the clutch as would seem to be the case from what you wrote.

The best shifting with a manual is done by “matching revs” before engaging the clutch, where “engaging” means releasing the clutch pedal. The easiest place to start is by googling “double clutching.” Once you’ve got the gist and practiced a little you can dispense with the “double” part; the “double” is simply a mechanism to make you think about each step and “slow down” the shifting while you practice and learn and train the muscle memory.

Come back here for further explanation or questions once you’ve done your homework

As for PDK, the DME automatically matches revs for shifts.

PDK does the better than all the other “automatic manual” transmissions. Audi/VW DSG in particular(*) “drags” the engine when it shifts. Many folks can’t “feel” it because they’ve never experienced a proper rev-matched shift.

(*) And thus “PDK” in the Macan because it’s really a Q5 box not actually Porsche PDK.

I'm probably not describing what I mean properly.

What I meant by the 1-2 second shift was the elapsed time between pushing the clutch in and going through the process where the car is fully in gear again. I'm probably overestimating this time but it's substantially slower than what the PDK can do.

I do rev matching while downshifting so familiar with what you're saying, but what I'm talking about really doesn't have anything to do with the shifting itself. It's the speed of how quickly the engine itself has to change from, let's say, 2k to 4k RPM. That's where I have the question.

On a manual transmission car this change in RPM doesn't happen in an "instant" like it does on a PDK. So if you were to observe the RPM gauge on a PDK, it would go over that 2k RPM range in milliseconds. But in a manual it's over a slightly longer period of time which in my mind would be less of a shock to the internals.

Again I'm likely doing an awful job explaining what's in my head but the rate of change is what I'm really inquiring about.

THAT is what I meant? 1 to 2 seconds, what are you doing, . . . your nails?

Ok I'm BAD at estimating time!!!

I just checked out one of my track videos and my shifts are under 1 second. But I still stand by my statement that my PDK is faster!

[worf]

I just tried to look up PDK shift speed and the first two pages of hits don’t provide a number. IIRC it’s on the order of 60 +/- milliseconds.

The engine can change speed on the same order.

[N_Jay]

The shift speed seems to vary on your driving style.
I find that quick throttle changes seem to tell the PDK that you want to drive aggressively.
That 'mode' sticks for 30 to 60 seconds.
I would love to see a map of the PDK logic.

[Prairiedawg]

As others have said, the PDK rev matches for you. The manual usually has a dual mass flywheel so it revs a bit slower. The pdk and engine are capable of revving instantly and are built to do it. I wouldn't loose a second of sleep. Plus these engines and transmissions have been out for more than a decade. If this was a problem we would know it by now.