[aeronca65tl]

I generally warm up most of our normal cars for 30 seconds or so. Within that time (if temps are moderate out) the fast idle motor will drop RPM to a reasonable speed. This applies to our GMC van or my wife's Honda. I know it's always best to warm up the car by driving it away as soon as possible but I hate putting a car in Drive when the engine is spinning around 1500 RPM....hence the 30 second wait,

[none of this applies to our antique British cars- they work better is I fiddle with the manual chokes and manage the throttle for several minutes]

But what to do with a PDK Porsche? I'm not talking about the manual gearbox here.

Again, I hate the idea of putting my Cayman in Drive if it's cold and turning 1300 RPM or so. Especially since it doesn't have a torque convertor (so all the "creep" is created by clutch slipping). So for now, I patiently wait for 90 seconds or so (when idle speed finally drops) and then I drive off. By the way, I never try to get the RPM to drop by "tapping" the throttle. The guys at PEC told me that's a waste of time and I never thought it was good idea anyway.

Anyone do anything different?

 

[717R]

Hi I read somewhere and am also somewhat inclined to move off at cold start (though not revving hard for the first 5 mins or so).

In practice however by the time I get the initial admin out of the way (belting up, firing up Spotify via BT, and putting away my wallet and phone), the revs would have just nicely stabilised.

That said, would like to hear what others do.

 

[GregW]

Start. Seat belt. Driving gloves. Cabin temperature set. Drive.

 

[Optical TDI]

I let idle a few min almost always. Even longer if it’s cold in garage. Not worried about the $0.25 in fuel it might cost.

 

[jimmuller]

I generally warm up most of our normal cars for 30 seconds or so. Within that time (if temps are moderate out) the fast idle motor will drop RPM to a reasonable speed.
...
[none of this applies to our antique British cars- they work better is I fiddle with the manual chokes and manage the throttle for several minutes]

But what to do with a PDK Porsche? I'm not talking about the manual gearbox here.
... By the way, I never try to get the RPM to drop by "tapping" the throttle.

Older cars, British or otherwise but seemingly especially British, used carburetors with a mechanical choke. The choke might be manual, or automatic controlled by a temperature-sensitive bi-metal strip. Automatic chokes became the norm for emissions reduction and because it was thought that humanoids wee too dumb to understand how to operate simple things.

The choke did two things, it enrichened the mixture until the manifold was hot enough to vaporize the gas and it kept the idle higher with a small cam and stop screw. Blipping the throttle took the mechanical force of the idle stop screw off the high-idle cam. That would release the choke as long as the temperature had risen enough for the bi-metal strip to want to release it. Normally that pressure on the cam would be released by the simple act of starting to drive. Nowadays all that is part of the engine control system.

With the PDK, I suspect it has no trouble dealing with that small rpm difference. So I just drive away, but gently because the owner's manual does say let the car warm before pushing it too hard.

As for letting a car warm up, I believe I recall I remember reading somewhere (not on the Internet, so it might not be true) that the reason not to do it was the possible accumulation of gas in the oil. When the cylinder walls are cold some gas will condense on them and not burn. It is is then scavenged off by the rings to mix with the oil. Inotherwords, you slowly dilute the oil with gas, making it thinner. If you drive enough with a warm engine those components in the oil should evaporate off, but if you trips are short it could shorten the engine life. Warming the engine at idle just makes it happen faster.

 

[JakiChan]

I do drive after starting the engine, but I don't turn to sport mode or get on it until the oil and water temps are past the blue part, which to me says that the car is up to operating temp.

 

[greywing]

I don't time it but suspect that after fiddling with seat belts and such, at least 30 seconds has transpired before I push off. WRT the clutch on the PDK it is my perception that as long as the brake pedal is firmly depressed, the clutch remains disengaged. This is certainly the case while at an intersection stop. I intentionally frequently use and appreciate the brake HOLD function at stop signals for that very reason - full dis-engagement of the clutch until ready to proceed when clutch engagement and brake release is initiated by application of the throttle. This is IMO a very well executed function by Porsche engineers.

 

[Optical TDI]

I don't time it but suspect that after fiddling with seat belts and such, at least 30 seconds has transpired before I push off. WRT the clutch on the PDK it is my perception that as long as the brake pedal is firmly depressed, the clutch remains disengaged. This is certainly the case while at an intersection stop. I intentionally frequently use and appreciate the brake HOLD function at stop signals for that very reason - full dis-engagement of the clutch until ready to proceed when clutch engagement and brake release is initiated by application of the throttle. This is IMO a very well executed function by Porsche engineers.

Does the Hold feature disengage clutches? It doesn’t feel like it. But pulling back on both parked certainly disengages.

 

[Calimerus]

I don't time it but suspect that after fiddling with seat belts and such, at least 30 seconds has transpired before I push off. WRT the clutch on the PDK it is my perception that as long as the brake pedal is firmly depressed, the clutch remains disengaged. This is certainly the case while at an intersection stop. I intentionally frequently use and appreciate the brake HOLD function at stop signals for that very reason - full dis-engagement of the clutch until ready to proceed when clutch engagement and brake release is initiated by application of the throttle. This is IMO a very well executed function by Porsche engineers.

I use a lot the HOLD function too. I prefer it to leaving the foot on the brake at a red signal stop.

But, it don't think it disengages the clutch, because as soon as you push the gas it moves.

If I've to stay a lot instead, I put into neutral pushing both PDK paddles.

 

[grasmere]

I use a lot the HOLD function too. I prefer it to leaving the foot on the brake at a red signal stop.

But, it don't think it disengages the clutch, because as soon as you push the gas it moves.

If I've to stay a lot instead, I put into neutral pushing both PDK paddles.

I also use hold a lot but it really never feels like the clutch is there, it feels disengaged but picks up beautifully on the throttle.

 

[jimmuller]

But, it don't think it disengages the clutch, because as soon as you push the gas it moves.

There is a detection mechanism happening because, as the manual describes, you can pull away and it releases the parking brake automatically. That it controls the PDK clutches wouldn't be a surprise.

 

[GregW]

I use a lot the HOLD function too. I prefer it to leaving the foot on the brake at a red signal stop.

But, it don't think it disengages the clutch, because as soon as you push the gas it moves.

If I've to stay a lot instead, I put into neutral pushing both PDK paddles.

On my car engaging the HOLD changes the rpm briefly (up) so I'm assuming something is disengaged.

 

[Calimerus]

On my car engaging the HOLD changes the rpm briefly (up) so I'm assuming something is disengaged.

If it worked like this, then it would be even better for the clutch.


In any case, it's the best automatic transmission I've ever tried

 

[greywing]

On my car engaging the HOLD changes the rpm briefly (up) so I'm assuming something is disengaged.

Exactly my perception and my reason for assuming the clutch is disengaged and not slipping. Although there's no way to know without confirmation from Porsche, it's my story and I'm sticking with it.