Westcoast

Ok now, that could be why it seems like, "what they heck did I do to cause that!"

I will have to be mindful of exactly when it grinds, coming out of first is quite a bit different then going into second... it would be interesting to know if there is a clutch bias valve in these cars, it should be visible on the PET?

SpydrGuy

As I've increased RPM during break-in of my Spyder, more or less following AP's suggested schedule, I've started to encounter the dreaded 1-2 grind. As far as I can tell it has never happened when shifting below 4500 RPM. Shifting around 5500 RPM seems to trigger it routinely, but not every time. I haven't yet gone above 6000 RPM so can't report on what happens at higher shift points. I don't think pulling slightly left or right makes any difference. As others have said, if you delay shifting for 1/2 a second after depressing the clutch it doesn't happen. It's frustrating that it grinds one time, then does not for the next 5 shifts, even though they're identical as far as I can tell. During daily driving I normally shift 1-2 at 4000 RPM so it's not something that would bother me every day, but it isn't right. I owned a 981 BGTS for 20K miles and never saw this problem. I'll report it to the service manager next time I'm in their vicinity. Perhaps if enough customers complain Porsche will look into it.

enduro

Prob not causal, but do these cars have a delay valve?

Westcoast

After a little reading on a clutch delay valve, it seems that it can also be called a clutch bias valve, if these are one in the same then I don't see how it would affect clutch disengagement... based on "standard" design.

From what I have read they are intended to standardize clutch engagement speed to prevent driveline shock but should allow quick non-impeaded disengagement of the clutch.

Archimedes

Had my second semi graunch today and it was clear that it was a result of me allowing the gear lever to shift slightly to the right towards 4th instead of being careful to come straight back to second. Over the rest of my drive, I then did at least 10 hard 1-2 shifts at 4.5k+ RPM being careful to bring it straight back. Perfect engagement every time. Given I’m usually careful like that and haven’t had any prior issues since nearly new, I’m beginning to think that at least some of these are driver error, like mine was.

Westcoast

By 'hard' is this a fast motion with no pause in between first and second?

And could you tell if the graunch occurred when coming out of first or going into second?

TomTarzian

That's what I thought as well, after my first two. After my third--and hopefully last--one I have begun to think the problem is my lack of attention to making a precise gear change--both lever position and not rushing the synchros. Applying that thinking, no graunches/grinds today, so maybe this is the solution? We shall see.

In my case, it definitely has only happened going into second, not coming out of first.

God bless,
TT

Archimedes

By hard I mean no pause, just a straight pull back from first to second. My two slight grinds have both definitely been when trying to enter second gear, not leaving first.

Westcoast

Thanks guys, I now have this on my list to confirm at what point it happens in my car, TBH I am pretty sure that it was going into second...

DocMo

Same here, I confirm it was entering into 2nd gear

Rennolazine

I stated this in another thread because i think i figured it out. If you are not off the throttle completely when u press the clutch and initiate the shift into gate 2, the synchro gets confused. Even if you roll into the gas hard and then let go/depress the clutch the synchro can get confused.
so unless im making a low rpm shift OR a redline shift (trans logic seems unaffected) i always wait for the revs to start dropping before engaging gate 2.
that said, its not a big deal compared to the ****show that is the 7mt, which in sport/sport+ mode, will blip the throttle for you on an upshift. That 1-2 upshift blip ruined the car for me. In the spyder the only time i want a rabid upshift is at redline, and the car gives me that every time, rewarding me with a nice chirp of the rear tires

TomTarzian

I suppose this is off topic, but the reason I chose not to get the Sport Chrono package in my wife's and my 991.2 911 C2 was to avoid anything like this. I chose the GT4 over a GTS 4.0--which is a fabulous car and probably in some ways better suited to my use--partly because in the GT4 the auto-blip is easily turned off...or never turned on!

God bless,
TT

Purekoryo

I never noticed the blip during upshifts with auto blip on? Actually while cruising and up shifting, the needle falls pretty quickly and falls a couple hundred rpm below engagement point.

unclemat

Can you elaborate? I wasn't aware of differences wrt auto blip between GTS and GT4.

Rennolazine

i am referring to the 7mt in the 911s. Different trans