2019 991.2 rev match bug (1st to 2nd)?
12-22-2018, 11:24 PM
#46
Rennlist Member
@ForeverCar, in doing some reading, I hate to say it but the manual transmission GT3 991.2 guys are also reporting the throttle blip on “upshift” in the GT3 rev match software mapping. It also sounds like there is not a disable button as again, it’s tied to Sport and Sport Plus modes. What the hell is Porsche thinking here....
12-23-2018, 02:08 AM
#47
SJW, a Carin' kinda guy
Rennlist Member
Rennlist Member
Fwiw, my GT3 seems to rev match by giving a little blip on upshifts as I shift slowly. My theory is let the computer figure out what to do, I just press the pedal and move the shifter.
I think rev match will significantly extend clutch life as it seems to work perfectly.
I think rev match will significantly extend clutch life as it seems to work perfectly.
12-23-2018, 09:24 AM
#48
Rennlist Member
The more I think about this I am starting to think that the engineers at Porsche probably had a good reason for incorporating the blip on the upshift. Perhaps due to the new turbo engine or the dual plate clutch? I assume I will learn to adjust to the car’s behavior, heck the computer is probably smarter than this old guy.
The good news for me is that others are seeing this in their 991.2’s and it’s not unique to my car.
The good news for me is that others are seeing this in their 991.2’s and it’s not unique to my car.
12-23-2018, 09:32 AM
#49
Rennlist Member
My experience: Sport mode is worse than sport +. Blip is less pronounced when you shift > 5500 rpm. Also improved after i got the akra muffler for some reason. Instantly.
My service manager drove with me in my car and I demonstrated it to him. He said this is how they mapped the ECU. Fwiw He has a 991.2 S manual also.
My service manager drove with me in my car and I demonstrated it to him. He said this is how they mapped the ECU. Fwiw He has a 991.2 S manual also.
12-23-2018, 10:25 AM
#50
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Fwiw, my GT3 seems to rev match by giving a little blip on upshifts as I shift slowly. My theory is let the computer figure out what to do, I just press the pedal and move the shifter.
I think rev match will significantly extend clutch life as it seems to work perfectly.
I think rev match will significantly extend clutch life as it seems to work perfectly.
12-23-2018, 02:19 PM
#51
Burning Brakes
Thread Starter
I’d like to understand why the high rpm blip on 1st to 2nd upshift. It makes the rpm mismatch by 30% or more (rpm higher than wheel speed dictates in 2nd gear).
This would add clutch wear and add “shock” to the acceleration (unless you wait for rpm to fall or slip the clutch). It does seem like it’s the way it’s been programmed. I am unable to understand why it’s good except for maximum acceleration (maybe). For turbo cars, I suppose it helps with turbo output. For GT3, it appears to be a flaw in implementation.
This would add clutch wear and add “shock” to the acceleration (unless you wait for rpm to fall or slip the clutch). It does seem like it’s the way it’s been programmed. I am unable to understand why it’s good except for maximum acceleration (maybe). For turbo cars, I suppose it helps with turbo output. For GT3, it appears to be a flaw in implementation.
12-23-2018, 06:55 PM
#52
Rennlist Member
So I drove the Carrera T for a couple hours today and seem to be aligned with the rev match behavior. I did confirm that if you turn off PSM the rev match program is defeated on both up and down shifts. So, if you want to experience the 911 circa 1972, turn off PSM by pressing and holding the button for a few seconds. Keep in mind that a brief press of the PSM button only
“limits” PSM functions and does not turn off PSM or rev matching.
It also seems that as my car is breaking in the manual shifter is getting much smoother (especially engaging 7th gear) and the exhaust sounds are getting more pronounced as the system starts to season. Very nice as I am just passing 250 miles. Almost time for a fresh tank of gas!
“limits” PSM functions and does not turn off PSM or rev matching.
It also seems that as my car is breaking in the manual shifter is getting much smoother (especially engaging 7th gear) and the exhaust sounds are getting more pronounced as the system starts to season. Very nice as I am just passing 250 miles. Almost time for a fresh tank of gas!
12-23-2018, 07:49 PM
#53
Burning Brakes
Thread Starter
Upshift is not rev match in my opinion. It’s over rev for no apparent good reason. If it’s rev match, I wouldn’t have to wait until the rpm drop for to ~3k from ~5k rpm after the blip.
If my GT3 behaves the same, I’ll likely persist more to try and get to the bottom of this. It’s programmed this way is not good enough of an answer for me.
If my GT3 behaves the same, I’ll likely persist more to try and get to the bottom of this. It’s programmed this way is not good enough of an answer for me.
06-23-2019, 04:37 PM
#54
I know this is an older thread - but came here looking for other like folks with this symptom. I am having a similar symptom occur on my (new to me) 991.1. The 1st to 2nd transition is difficult in itself, and startling if this blip occurs. Seems to be normal and accepted?
06-23-2019, 06:24 PM
#56
Rennlist Member
I haven't noticed any throttle blip in mine when shifting from 1st to 2nd. The rev matching feature during downshifts is quite noticeable so I would (perhaps) notice it. I am slow shifter.
First to second is slow anyway in cold weather. Resists going into second from first.
2018 C4S.
First to second is slow anyway in cold weather. Resists going into second from first.
2018 C4S.
06-23-2019, 07:58 PM
#57
Rennlist Member
Its stupid programming. GT3 doesnt have upshift blip but it DOES gave a bunch of other useful features like launch mode, no lift shift etc. Why? See reason 1
I haven’t given up on this. The car is a solid 9/10. With this fixed it would be 10/10.
Its still early in the tuning game and if I still have the T when TCU tunes roll out, we will be triumphant
I haven’t given up on this. The car is a solid 9/10. With this fixed it would be 10/10.
Its still early in the tuning game and if I still have the T when TCU tunes roll out, we will be triumphant
06-23-2019, 08:00 PM
#58
Rennlist Member
I haven't noticed any throttle blip in mine when shifting from 1st to 2nd. The rev matching feature during downshifts is quite noticeable so I would (perhaps) notice it. I am slow shifter.
First to second is slow anyway in cold weather. Resists going into second from first.
2018 C4S.
First to second is slow anyway in cold weather. Resists going into second from first.
2018 C4S.
06-24-2019, 10:01 AM
#60
Rennlist Member
