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    Guess I wuz lucky

    Was traveling on the toll road the other day when a brand new Aston Martin Vantage passed by. I dropped in behind him and followed a while. Finally, he floored it and took off. I was in sixth gear. No acceleration there. So I blipped the accelator and grabbed for fourth. Missed it somehow and got second instead. When I released the clutch I watched in horror as the tachometer pegged at over 8500 rpm. I released the clutch instantly expecting at any moment to hear a 'clunk, braaaaaaaaat'. But it was quiet and seemed to be running normally. I drove on to work and it hasn't given me any trouble. How badly can you over-rev these engines anyway and still get away with it?

    Re: Guess I wuz lucky

    Oh, BTW, the car is a 2006 Carrera Cabriolet. 19" Carrera Sport wheels and the Sport Exhaust system plus some other non-performance options.

    Re: Guess I wuz lucky

    A couple of things happened. First the rev limit over-run has been recorded in your P-car's computer. Second, the fuel supply should have been momentarily cut off as you exceeded red-line.

    I know a few other Rennteamers have over-revved their cars. I am sure they will post their results.

    Re: Guess I wuz lucky

    Quote:
    Puffy911 said:
    A couple of things happened. First the rev limit over-run has been recorded in your P-car's computer. Second, the fuel supply should have been momentarily cut off as you exceeded red-line.




    It is worse than that. What you describe is a normal type 1 rev limiting event - harmless. What the OP describes is a true type II over rev. It is dangerous, it is recorded and seen by PAG as driver error, with possible implications on future warranty work.

    I hope that the OP learned his lesson... actually 2 lessons, including proper shifting.

    Re: Guess I wuz lucky

    Takes a moment to do - you have my sympathy.

    Not dangerous, but embarrassing - I've been at the head of a queue at the lights before, and shifted into reverse rather than first trying to take off quickly after not noticing the lights had changed. Well it woke the guy behind me up!

    Is this 6-to-2 mistake easier to do in a LHD car than a RHD one I wonder?

    Re: Guess I wuz lucky

    Like A.Dias says, this over rev is worse because the revs are not driven up by the throttle like in a Type I, in which case the rev limiter cuts the fuel and does not allow the revs to climb any higher than the rev limiter.

    But in a type II, since you are downshifting its the traction of the wheels that overdrive the revs and there is nothing to stop them so the revs can climb anywere beyond the rev limit being potentially very dangerous. Whats more its registered on the ODB (which registers exactly how high and how long it overreved) and may be used by the delaer to void warranty if any subsecuent damage may arrise.

    As a precaution, when downshifting two gears its often best to still perform the stick motion of the in-between gear without declutching in the inbetween gear, i.e. 6 to 5 to 4, instead of 6 to neutral to 4. This places the stick in a position were its much harder to miss the gear and its just as quick, or actually even quicker since you don't have to fidget around the last gear just to make sure you dind't miss it, and its a very fluid one-two motion with the stick.

    Re: Guess I wuz lucky

    i don't want to scare you, but my similar experience (according to porsche) resulted in my engine dying about 4 months later. the warranty claim was denied, porsche chipped in 5k on a new 11k engine. for what it's worth... good luck.

    Re: Guess I wuz lucky

    For peace of mind, I'd have it tested for any damage. Good luck.

    Re: Guess I wuz lucky

    Thanks for the comments. Yeah, I can't believe I made that mistake. I did a Google on overrevs to see what might have happened inside the engine. Several mentioned the overrev being recorded, so I guess I'm hosed on that point. I really didn't find anything specific to a Porsche engine over rev, but saw several posts concerning BMW engines bending exhaust valves on a type 2 overrev. It seems about the only check you can do when this sort of over rev occurs is to do a compression check. Also, I did see one article concerning stretched connecting rod bolts.

    When you replaced your engine, did Porsche tell you exactly what was damaged? My engine seems to be running fine at the moment. I might, just might, be OK.

    Re: Guess I wuz lucky

    Once I moved onto a 6-speed it did take me a little time to adjust from a 5. I always have to remember which gear I'm in within my mind, and always remember that with the lever out of gear it defaults to the position be tween 3 and 4,--neutral in the center. You have to remember that.

    dan

    Re: Guess I wuz lucky

    BTW, is that the fuel cutoff working when you keep your foot on the gas and put on the brakes at the same time?

    Why do it? To test the fuel cutoff of course.

    Re: Guess I wuz lucky

    Nothing you can do now. If it was me, I would just keep on driving.

    Re: Guess I wuz lucky

    An easy mistake to make - potentially costly; my advice here is to relax with the gear shift (don't strangle the shifter in a moment of adrenaline fuelled tension!) the soft touch always gives you a smoothe shift into the default 3rd/4th gear plane. BTW, having driven both there's no difference between LHD and RHD with this issue in my opinion.

    Re: Guess I wuz lucky

    I've blown a couple of motorbike engines in motorobike engine cars on track. Changed down to quickly through a couple of gears (too exicitied!!!). Bent a valve one time (the springs can't keep up and the timing goes out of sync.) and the other broke a con rod.

    I can't see that you can check much unless you strip the engine down, which is expensive in any case.

    My turbo tiptronic won't let me change down at the wrong time

    Bob

    Re: Guess I wuz lucky

    Quote:
    eljeffo64 said:
    An easy mistake to make - potentially costly; my advice here is to relax with the gear shift (don't strangle the shifter in a moment of adrenaline fuelled tension!) the soft touch always gives you a smoothe shift into the default 3rd/4th gear plane. BTW, having driven both there's no difference between LHD and RHD with this issue in my opinion.



    Correct. But... to be smooth with the shift takes time... and there goes the imagined advantage of a manual vs tip and that is hard to swallow for some people.

    Re: Guess I wuz lucky

    Well, what's done is done. I would just forget it happened and if [beep] hits the fan at the dealership blame it on their shop kid!

    Re: Guess I wuz lucky

    I have done this too

    Re: Guess I wuz lucky

    If your engine goes bad, DENY DENY DENY and raise bloody murder with the shop.

    I don't care what the BLEEPIDY - BLEEPIN computer says happened. If this BLEEPIDY $80K car's engine can't handle a momentary overrev without major damage, then the BLEEPIDY engineers are at fault not making their design robust enough for a street car. I can accidently overrev a BLEEPIDY Toyota Prius and it won't blow itself all to hell later on.
    Fix my BLEEPIDY car or my attorney is the next person I speak with, the press is the second, Porsche members the third, better business beareau the fourth.

    Re: Guess I wuz lucky

    Quote:
    Heist said:
    If your engine goes bad, DENY DENY DENY and raise bloody murder with the shop.

    I don't care what the BLEEPIDY - BLEEPIN computer says happened. If this BLEEPIDY $80K car's engine can't handle a momentary overrev without major damage, then the BLEEPIDY engineers are at fault not making their design robust enough for a street car. I can accidently overrev a BLEEPIDY Toyota Prius and it won't blow itself all to hell later on.
    Fix my BLEEPIDY car or my attorney is the next person I speak with, the press is the second, Porsche members the third, better business beareau the fourth.



    Yeah... it figures, make the deed and blame the manufacturer. I've long though that many of the Internet reports of failed Porsche engines are probably driver induced. By a strange coincidence those cars are all manual cars... Nobody should buy a used car with a recorded type 2 overrev. I certainly would not.

    > If this BLEEPIDY $80K car's engine can't handle a momentary overrev without major damage, then the BLEEPIDY engineers are at fault not making their design robust enough for a street car.

    Stating the above, you obviously know nothing about high performance engine design. If you think that way, you should by a luxury auto limo - then your statement "may" apply. I qualify the word "may" because I've seen morons destroying perfectly good and well designed auto trannys and of course, blaming the car afterwards.

    BTW... you are correct. You cannot cause a type 2 overrev on a Prius. The system does not allow you that driver error. If you have a Prius that is definitely the car for you.

    Re: Guess I wuz lucky

    There's some interesting personal ethics on display in this thread...

    If you execute a money shift..the blame is yours. Suck it up. Move on.

    Otherwise either skill up and understand the risk..or drive a Tip.

    Re: Guess I wuz lucky

    Well, it's been several weeks since the incident and the motor still runs fine. One of my daughter's former boyfriends is a Toyota mechanic. He advised me to listen carefully for any knocking or tapping sounds, especially at startup. I haven't heard any.

    This problem would be easy enough to lock out. One could put a gizmo either on the shifting shaft as it exits the back of the transmission, or preferably, build it into the transmission itself. A solenoid would simply lock the first/second shift rail in neutral the moment the Motronic senses vehicle speed above, say, sixty miles per hour. Since engine RPM in second is simply MPH times 100, that means you wouldn't be allowed into second if it meant the engine RPM would exceed 6000 upon clutch release. The solenoids would be fail-safe. That is, if they failed they would permit shifting, not prevent it.

    How about it, Porsche? I can't be the first person in the world to have thought of this. Your design already prevents Type I overrevs. It would be easy enough to prevent Type II overrevs as well. Of course, this is not a problem with the Tiptronic, but until a sequential shift transmission is introduced, it will remain the manual transmission for me.

    Re: Guess I wuz lucky

    Quote:
    Greentree said:...This problem would be easy enough to lock out. One could put a gizmo either on the shifting shaft as it exits the back of the transmission, or preferably, build it into the transmission itself. A solenoid would simply lock the first/second shift rail in neutral the moment the Motronic senses vehicle speed above, say, sixty miles per hour. Since engine RPM in second is simply MPH times 100, that means you wouldn't be allowed into second if it meant the engine RPM would exceed 6000 upon clutch release. The solenoids would be fail-safe. That is, if they failed they would permit shifting, not prevent it.

    How about it, Porsche? I can't be the first person in the world to have thought of this. Your design already prevents Type I overrevs. It would be easy enough to prevent Type II overrevs as well. Of course, this is not a problem with the Tiptronic, but until a sequential shift transmission is introduced, it will remain the manual transmission for me.

    Personally I don't want any more "nanny state" safety gizmos on my cars (or motorcycles). We already have ABS that can't be disabled (they don't even teach threshold braking at most high performance driving schools anymore), traction and stability control that eventually will not be allowed to be disabled (tip over avoidance), lane deviation warning systems, active cruise control, rev limiters (never saw them on carbureted vehicles) and even motorcycles with technology that will not allow the motorcycle to wheelie.

    With some of the attitudes I have witnessed in this tread it may not be too far off that the manufacturers do develop such a safety system to protect themselves from unscrupulous customers who are not willing to accept responsibility for their own ineptitude and lack of basic driving skills.

     
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