Question about PDK delay from dead stop - I'v never had a Porshe or anything like PDK
 

Hi all,

I just got my first Porsche (2009 997.2 S Cab) and it has the PDK transmission. I think it's great, but there seems to be a noticeable delay (maybe .5 seconds) from the time you floor it from a dead stop to the time the car takes off. Is this normal? I do not have the sport/sport+ option but if i added it would it help improve this. TIA

theres several spots that feel funny.
http://forums.rennlist.com/rennforum...dk-tuning.html

So how much did you increase the idle? Is that what gets rid of the delay or is it the re-programming? TIA

Without Sport Chrono package, the PDK unit (as well as manual for that matter) does have a softer pedal with a little more delay. With SC in Sport Mode, you have a noticeably more sensitive pedal with much less delay. Sport Plus just puts the car in full-on race mode.

You can now add SC through an orderable option (Suncoast has it here: http://www.suncoastparts.com/product//9X7SM.html).
I've also hear decent feedback about the SprintBooster device. This will also sharpen pedal feel.

No delay. A delay can happen if you come off brakes and it's due to the hill assist; actually not a delay just the feeling you have noticing the brakes disengage.

I just assumed this was the time it took for the clutch to engage after releasing the brake.

With a traditional auto (non-PDK), you can apply power to the wheels right away through the torque converter. But with PDK, the clutch is disengaged when you're at a stop, and it needs to time to engage when you release the brake and start to apply throttle. Is this right?

No delay (well perhaps milliseconds). What people feel is the hill-assist action, which is triggered even backing off of a driveway. Even that can be eliminated allowing the car to roll by itself and only then apply throttle.

Actually I am in Florida so I rarely even see a hill.

Yes you are right. I just thought it would respond a bit quicker than it does.
I guess I'm thinking automatic instead of Manual tranny.

No, not measurably. As Tony says, the delay will be in the millisecond range. Even if you just lightly touch the throttle, the clutch will engage very quickly. PDK includes "crawl mode" that lets you move away from rest in a parking lot without fully engaging the clutch and thus going too fast.

I'll take Tony's word for it regarding the hill feature. With a manual transmission, I've never felt the brakes release at all because it happens so smoothly as I engage the clutch. Of course, we don't have serious hills around here. If the car were holding on a steep slope, I can imagine feeling the transition, but as it is I only know intellectually that the brake is working because I don't have to 'catch' the car from rolling backward. I know that, but I don't feel the car substituting for me.

So... you never back off a sloping driveway? a curb? or what have you? Of course you do, and that's when you feel that transition. I have 10,000 miles of PDK driving, and what I described is what happens.

Gary: on a manual you do not feel the hill-assist on light slopes because the brake releases as you engage the clutch, and that is slower than what a PDK does. On a PDK, 'crawl mode' is on and if you quickly release the brake and accelerate the clutch is already disengaged and what one feels is the brake releasing; especially if you came out from a reverse. I can repeat that 100% of the time. However, if I let the car roll - crawl - for a split second, the brake jolt does not happen. People, in general, do not understand the system mechanics and are conditioned by previous experiences and interpret a new system based on what they know; it's just normal. :)

From a stand stil and you floor the car...PDK has to engage the clutch. Put it in Sport Plus mode and this happens faster....or if you are drag racing use Launch Control.

That sounds right to me, Tony. I'm sure we could program a smoother transition if it seemed important enough, but as has been said, we don't put supercomputers in cars and they need the bandwidth and code space for a lot of demands imposed by the different subsystem designers. This sounds like a desirable, or at least neutral, trait, so they simply don't spend time and computer resources hiding the effect.

Gary

Sports car designs are already too soft in my book. Watch the upcoming 991 GT. Or is it a lounge-looking 911? :)