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    997 Turbo tiptronic S- lurch/hesitation possible ?

    I know I'm posting this question prematurely but after my Cayenne Turbo experience, this is my only concern about my 997 Turbo coming this fall. The hesitation and / or lurching was the subject of countless numbers of posts on the Cayenne board and was the reason I parted with an otherwise great vehicle. Am I going to have to do the same with my new turbo tip?

    Re: 997 Turbo tiptronic S- lurch/hesitation

    I will let RC chime in on this, but he said the lurching on the Cayenne was there on purpose to tame the car. Thus I doubt it would be on the 997TT.

    Did you get the DME update before getting rid of your TT? It really helped for some including me.

    Re: 997 Turbo tiptronic S- lurch/hesitation

    Quote:
    RC said:
    9. I highly doubt that the VTG technology will be introduced on the new Cayenne Turbo but it can never be excluded. The lag is actually "artificially" induced, I don't want to brag about it again (check our archives) but apparently it has been done for safety reasons.
    Just imagine this: soccer mom, red light, mom presses throttle down fully, Cayenne Turbo S jumps forward in an instant, in front of soccer mom, another car stops suddenly, soccer mom already has a huge speed and just released the foot from the throttle to operate the brake.... BOOOOMMM. We're talking about a 2.5 ton monster, an instant acceleration would be dangerous for many drivers. Unfortunately, the lag can be dangerous too.



    Re: 997 Turbo tiptronic S- lurch/hesitation

    I can't speak to the Cayenne Turbo hesitation problem, but I do know that most automatic transmisions have a hestitation problem to one degree or another because they are programmed to maximize fuel economy. When you take your foot off the gas, or maintain a constant low level of acceleration, most automatic transmissions are programmed to upshift to the highest gear possible to achieve the lowest engine revolutions and the greatest fuel economy (and least engine noise). Unfortunately that puts you out of the engine's torque band. So when you press the gas, the transmission has a brief moment where it tries to accelerate in the current gear but can't due to lack of torque, then another moment or two where the transmission downshifts to a lower gear, and then suddenly the engine revs up and you go. The problem is even more pronounced in an automatic transmission whose torque converter does not have a lockup, since you add another moment for the torque converter to lock up before the car goes anywhere. (I would be very surprised if that wasn't the true story behind the Cayenne hesitation problem, which Porsche is too embarrassed to admit because they didn't design the transmission and can't reprogram it, but I could be wrong.) This problem can be solved to some degree by programming the automatic transmission to stay in the engine's torque band, but fuel economy would suffer. The 997tt's torque band is extraordinarily wide, down to 2k rpm (!), so if any automatic transmission could get this right, it would be the 997tt tip. Personally I'd wait and see before ordering a 997tt tip. It's so easy to get this one wrong (every automatic car I've ever driven has the problem) and so hard to get it right (no automatic car I've ever driven has solved this problem), that the smart money says that its unlikely (but not impossible) that Porsche will get it right for the 997tt tip.

    Re: 997 Turbo tiptronic S- lurch/hesitation

    Quote:
    kkeating said:
    I know I'm posting this question prematurely but after my Cayenne Turbo experience, this is my only concern about my 997 Turbo coming this fall. The hesitation and / or lurching was the subject of countless numbers of posts on the Cayenne board and was the reason I parted with an otherwise great vehicle. Am I going to have to do the same with my new turbo tip?



    The Tip itself isn't the real problem on the Cayenne Turbo but the throttle setup. Shifting times could be slightly better but what annoys me most is throttle hesitation.
    I talked to two persons who already have driven the 997 Turbo. There is not even the slightest hesitation present, not from standstill (goes off like a rocket, saw a short video) and not during driving, on the contrary. Like one of the persons said: "You have to watch out not to be too fast all the time..." And finally: the Tiptronic in the Cayenne Turbo is made by the japanese manufacturer Aisin, the Tiptronic in the 997 Turbo is actually a modded Mercedes automatic tranny. Just for the book.

    Re: 997 Turbo tiptronic S- lurch/hesitation

    Quote:
    RC said:
    Quote:
    kkeating said:
    I know I'm posting this question prematurely but after my Cayenne Turbo experience, this is my only concern about my 997 Turbo coming this fall. The hesitation and / or lurching was the subject of countless numbers of posts on the Cayenne board and was the reason I parted with an otherwise great vehicle. Am I going to have to do the same with my new turbo tip?



    The Tip itself isn't the real problem on the Cayenne Turbo but the throttle setup. Shifting times could be slightly better but what annoys me most is throttle hesitation.
    I talked to two persons who already have driven the 997 Turbo. There is not even the slightest hesitation present, not from standstill (goes off like a rocket, saw a short video) and not during driving, on the contrary. Like one of the persons said: "You have to watch out not to be too fast all the time..." And finally: the Tiptronic in the Cayenne Turbo is made by the japanese manufacturer Aisin, the Tiptronic in the 997 Turbo is actually a modded Mercedes automatic tranny. Just for the book.



    I was about to wryly reply, but RC "beat me to the punch." To say the 997TT-TipS might have a "hesitation problem," is kind of like saying the devices we jettisoned over Hiroshima and Nagasaki were doubtfully able to decisively end the Pacific conflict (the position of a college professor of mine) merely because we later created a more powerful weapon thereafter that vaporized the Bikini Atoll....

     
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