carbondan

Hey all,

I just took delivery of a 991.2 GT3 Manual last night and am getting familiarized with it.
When I try to rev match a downshift, the car doesn't actually rev much at all when I try to do it like is normal for any other car.
Sport mode does the auto-rev match just fine the way I'd expect it to allow me to, but I want to do it myself with sport mode off.
If I try to blip the throttle, it barely responds.
If I put the clutch in and then hold the throttle down, it puts it into a rev-limited mode, like a launch control (see video).
If I blip the throttle twice quickly, it will respond the way I expect it to.

Any thoughts as to what I may be doing wrong here and how to get it to act normally?

In the video:
First attempt is a normal attempt to rev match (I'm not actually changing gears here because I had to hold the camera). It doesn't respond to the blip like it really should.
Second attempt is clutch in, floor and hold the gas.
Third attempt is clutch in, stab and release the gas twice - basically how I would expect it to act, except I wouldn't want to have to hit the gas twice to get it to respond like normal.
https://streamable.com/blnd9

maspirito

That ain't right
as they say in Kentucky

FourT6and2

Never seen that before. In my car, I can manually blip the throttle to whatever RPM, as long as I'm actually moving. Only time car prevents you from revving is at idle, while stopped. Can't go over like 5K or something then. But if I want to manually rev match, I can.

carbondan

Maybe I have some setting misconfigured?
Any ideas? Can't find anything particularly helpful within the manual.
If I put it in sport mode, the ecu handles the downship blipping perfectly, just won't allow me to do it with sport mode off.
Also, if I brake hard/heavy deceleration and try to do a heel-toe downshift & blip, it does often work properly, but only after heavy decel and with higher revs.

FourT6and2

How are you attempting to rev match. You press in clutch, then what? You change gears and then you try to blip throttle? Or you blip throttle and then try to change gears? Or you go to neutral, then press in clutch and blip and then change gears? Otherwise known as double clutching. What method are you using?

FourT6and2

That fluttering farty sound in your video doesn't sound right either, btw.

carbondan

Press in the clutch, and within .5 seconds blip the throttle and move the gear lever from say 4th to 3rd, more or less simultaneously. Probably start the blip as I'm out of the first gate and on my way into the target gate, it's all one fluid motion like normal.
I've been driving manual daily for 15 years now so I am truly doing it correctly, there's no funny business going on on my end lol. I think it's safe to rule out extreme user error in this case.
In that video, all I'm doing is putting the clutch in and blipping the throttle without moving the gear lever (since I need to hold the camera and wheel), but it acts the same either way.
If I double clutch, it works properly, but I can't imagine that is normally required to get it to blip freely.
If I also blip the throttle (so stab and release) and THEN blip once more, it works properly - that's what is shown on the third attempt.
Aside from that, the car drives perfectly, no issues whatsoever. Did about 200 miles on the mountain roads this morning.

Thanks for helping me try and troubleshoot this... it's very strange.

carbondan

https://streamable.com/feo2l
Here's another video showing what I mean for the double-blip attempt.
In this video, clutch is in, I stab the throttle once and it acts basically dead/limited. Stab the throttle again a second time (exact same pressure, duration etc), and it revs freely as would be expected on the first attempt.
Also, if I put it into neutral, release clutch, and rev, it revs freely.

So really, the simplest explanation of the symptom is that when I have the clutch in and try to blip the throttle once, it does not respond properly.

FourT6and2

Weird.
That doesn't happen in my car. I'd bring it into the dealer since it's under warranty.

carbondan

Dang. Looks like it's heading that way
I emailed the dealership that I bought the car from (very large Porsche dealership, well known and active on this board).
I'll keep everyone posted on how things turn out.

carbondan

Can we take a poll?

.2 GT3 manual owners -- If you are cruising in gear, put the clutch in and within .5 seconds or so, hold the throttle down, does your car rev freely or get locked up in a more or less static RPM range like a rev limiter? As shown in the video.
I'm wondering if this is some how related to the no-lift shifting programming...

aaa335

Just tried it, my car does not do what yours is doing in the video. It will rev freely if the clutch is depressed and I hold the throttle down. I have never heard that fluttering sound your car is making in 1,600 miles.

FourT6and2

Yeah, that fluttering sound is strange. Something's definitely not right.

carbondan

Thanks guys.

francisluu

I've noticed a lot of nuances with the throttle mapping in the manual GT3 (and Touring, of course). One way to demonstrate some of these nuances is to try no-lift shifting *not* at full throttle. You'll notice the revs will drop to where they should be in the next gear (lets say from 2nd to 3rd) and hold, similar to having a rev limiter at those revs. Once you hear the flutter, try flooring the throttle — definitely is like a rev limiter

Similarly, do the same thing as above (no-lift shift at partial throttle as you would around town) but instead of shifting from, say, 2nd to 3rd, just leave it in 2nd and don't change to third. It'll do the same thing and hold revs (with the fluttering rev-limiter sound) for 2nd gear. The computer seems to be helping you shift if under any amount of throttle while the clutch is depressed.

So if you're blipping your own downshifts, you may be hitting the throttle on the earlier side and triggering the rev-limit-while-in-current-gear scenario. Obviously you aren't pressing the throttle for a long period of time so when you move to complete the downshift, you aren't depressing the throttle pedal anymore.

In summary, the car allows no-lift shifting even at partial throttle. This will hold revs for either the gear you're gonna want to be in or for your current gear.