Selo

In my new GTS Cab, now that it's beyond the break-in period, I'm starting to get to know the car better. In zooming around town and playing a little bit on some exit ramps and such, I'm noticing an odd clunking from the rear-end when heel-toe shifting. It's not terrible, but I don't think it's normal either. My service manager at the dealership says he thinks that PSM/PASM get "confused" during these maneuvers, which I don't really buy.
I've tried it with PASM turned off and it seems to do the same thing, and my 08 base Cab never had any similar issues, but it didn't have PASM.
What could the subtle clunking be?

Mike in CA

I don't buy the SM's explanation either. Just curious, are you rev matching or actually doing a full double clutch downshift? Just rolling your foot off the brake to blip the throttle while engaging the clutch and just before shifting (rev matching) definitely shouldn't cause a problem with PSM. I suppose it's somehow possible that engaging/disengaging the clutch twice on a true DC downshift could mess with PSM, but it seems really unlikely. I don't see how PASM could be affected under any circumstance.

Selo

I'm heel-toeing as I was taught. Not rolling my foot off the brake, but using the ball of my foot to continue applying the brakes while blipping the throttle with the outer edge of my foot or heel to rev-match for the downshift. I'm not releasing the brakes at any point during the process.
I consider simple rev matching to be when braking isn't involved.

f1pilota

Doesn't sound right at all. You know Porsche tests the cars with professional test drivers who are intimately familiar with heel toe. Did you make any adjustments to your pedals? I feel like the gas is a bit far out of reach even under heavy braking....

Mike in CA

I'm not questioning your technique, I was just wondering whether you were rev matching or actually double clutching. Both are often done while "heel and toeing" as you describe, with your foot on the brake and using the side of your foot or heel to blip the throttle. My earlier description of rolling your foot off the brake was poorly written; I should have said rolling onto the throttle.

My thought was that actual double clutching might, although unlikely, be messing with your PSM. But it sounds like DC is not what you are doing.

cnachris

LSD equipped?? Heel/Toe "ing" into tight corners??

PJorgen

Maybe your car is a PDK? (just kidding)

Selo

It is LSD equipped, but I'm not necessarily experiencing it only when heading into corners. It happens on straights too.

997_rich

Just doublechecking.. you're at low mid RPMS on the highway, you exit to a hard turnoff and you simultaneously step on the clutch and break relatively hard (1) then you shift into lower gear(2) while doing this you roll your foot and blip or blip and hold to higher RPM (3) then you take your foot off the clutch and brake (4) then you throttle (5).

OR if you're double clutching....you're at low mid RPMS on the highway, you exit to a hard turnoff and you simultaneously step on the clutch and break relatively hard (6) then you shift into neutral(7) then you take your foot off the clutch (8) while doing this you roll your foot and blip or blip to higher RPM (9) and step back on the clutch (10) then you shift into lower gear (11) then you take your foot off the clutch (12) then you throttle (13).

At which point 1-12 are you hearing the clunk? which action is it associated with (clutch on or off? throttle, brake etc)? what happens when you hear the clunk? RPMs jump? RPMS drop? around what RPMS does it happen? car lurches forward? car lurches back?

this info will help us determine what the issue is