2019 991.2 rev match bug (1st to 2nd)?
10-11-2018, 11:17 AM
#1
Burning Brakes
Thread Starter
2019 991.2 rev match bug (1st to 2nd)?
I recently got my 2019 991.2 C2 GTS manual. I have driven about 1000 miles now. I’ve noticed a strange, bug-like behavior, of the rev match implementation. Previously, I experienced Porsche rev match implementation for 7 month with a 2017 718 Cayman S manual.
During 1st to 2nd upshift, instead of a natural drop of rpm, the throttle would blip to what would be a perfect shift back into 1st. This erroneous blip then adds additional time for rpm to drop in order to engage 2nd smoothly. This only happens in sport or sport+ mode and only for 1st to 2nd. It also doesn’t happen on light throttle application or extra slow (long duration) gear lever movement. In other words, it only happens if throttle opening is moderate+ and the shifter movement is relatively swift.
Has anyone experienced this symptom? Does anyone know what sensors are used for the rev matching implementation? It’s surprising to me that taking a longer time to shift cause this to not reproduce (but I suppose the ECU has timers). This is quite puzzling to me and I’m seeking the wisdom of the amazing experts on this forum. Unless I get lucky to connect with a great technician at the dealership, I doubt it’ll be straightforward to get this resolved by my local Porsche dealership.
During 1st to 2nd upshift, instead of a natural drop of rpm, the throttle would blip to what would be a perfect shift back into 1st. This erroneous blip then adds additional time for rpm to drop in order to engage 2nd smoothly. This only happens in sport or sport+ mode and only for 1st to 2nd. It also doesn’t happen on light throttle application or extra slow (long duration) gear lever movement. In other words, it only happens if throttle opening is moderate+ and the shifter movement is relatively swift.
Has anyone experienced this symptom? Does anyone know what sensors are used for the rev matching implementation? It’s surprising to me that taking a longer time to shift cause this to not reproduce (but I suppose the ECU has timers). This is quite puzzling to me and I’m seeking the wisdom of the amazing experts on this forum. Unless I get lucky to connect with a great technician at the dealership, I doubt it’ll be straightforward to get this resolved by my local Porsche dealership.
10-11-2018, 01:55 PM
#2
I'll have to test this out, I also have a 2019 Manual GTS, but hadn't noticed what you are describing, but I've also never had another Porsche manual with rev matching, so nothing to compare to. I'll pay attention driving home today.
10-11-2018, 05:00 PM
#3
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It can be turned off, right? My last car, a 2017 Corvette, had rev-matching and I hated it...so much better to blip myself.
10-11-2018, 05:31 PM
#4
10-11-2018, 08:55 PM
#5
Burning Brakes
Thread Starter
Rev matching is off in normal mode but cannot be turned off in sport or sport+. I’m ok with it being on. I just think I’m running into a buggy behavior and not sure if it’s specific to my car or an implementation issue.
HMBGTS, thank you for checking. I’d love to hear your perspective.
HMBGTS, thank you for checking. I’d love to hear your perspective.
10-11-2018, 10:11 PM
#6
Rennlist Member
I have had this happen a few times so far on my 2019 T and planned to let my dealer know.
It seems to happen with lazier/slower shifts. Where I wind the engine out in first a bit then shift slower to let the engine wind down naturally during the shift.
During the shift the engine blips. Very annoying. It does not do this in normal mode.
It seems to happen with lazier/slower shifts. Where I wind the engine out in first a bit then shift slower to let the engine wind down naturally during the shift.
During the shift the engine blips. Very annoying. It does not do this in normal mode.
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10-11-2018, 11:32 PM
#8
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Here is some interesting info on rev matching...you can actually disable it: https://rennlist.com/forums/991/1046...in-i-mode.html
10-12-2018, 12:11 AM
#9
Burning Brakes
Thread Starter
Turning rev matching off is an option. However, I’m looking for a way to keep rev matching on but without this seemingly buggy/unintentional 1st to 2nd *upshift* throttle blip that’s annoying.
Looks like this happens for others as well. If you get to the bottom of this, please keep us posted.
Looks like this happens for others as well. If you get to the bottom of this, please keep us posted.
10-12-2018, 03:01 PM
#10
Tried to observe this yesterday on my way home, and today on my way into the office. Maybe I'm not replicating the shift timing the same, but didn't see a difference from standard to Sport and didn't notice any odd throttle blip in Sport from 1-2. Then again, i'm at 550 miles on the car, so i've not wound up on the tach passed 3750 yet. Maybe its irrelevant to have any kind of break in period for this particular car, but its always been my habit to not go too hard on the engine or transmission for the first 1K miles in a new car.
10-12-2018, 03:29 PM
#11
Rennlist Member
I don't think it's a bug. The only time I experience this is under hard acceleration and the software keeps my revs up while I upshift. Apparently, I'm a slow shifter ... Doesn't do it under normal or even moderate driving.
I think this is all intended design/behavior on the part of the software.
I think this is all intended design/behavior on the part of the software.
10-12-2018, 07:46 PM
#12
Burning Brakes
Thread Starter
Keeping rev up (if it drops below) for 2nd gear engagement could make sense. However, this is a blip to much higher rpm that would be perfect for shifting back into 1st. I cannot see how this would be as intended.
10-12-2018, 07:50 PM
#13
Burning Brakes
Thread Starter
Thanks for checking. I don’t think I’ve experienced this at lower rpm as well. Please check it out as you explore more of the rev range. Moderate throttle, sport/sport+ mode, say 5K rpm, and “normal” 1st to 2nd shifter movement speed pretty much reproduce this erroneous behavior consistently.
Tried to observe this yesterday on my way home, and today on my way into the office. Maybe I'm not replicating the shift timing the same, but didn't see a difference from standard to Sport and didn't notice any odd throttle blip in Sport from 1-2. Then again, i'm at 550 miles on the car, so i've not wound up on the tach passed 3750 yet. Maybe its irrelevant to have any kind of break in period for this particular car, but its always been my habit to not go too hard on the engine or transmission for the first 1K miles in a new car.
10-12-2018, 08:29 PM
#14
Rennlist Member
This upshift throttle blip is worst for me in sport mode (smoother but present in sport plus).. especially after fast throttle to moderate rpms (3-5k rpm). Makes nailing a 1-2 shift tricky. Still happening after 3k miles. Rest of shifts are butter. I made a thread about this in july. Im thinking about asking cobb twhether they can tune an upshift rev matching delete if possible 
10-12-2018, 09:03 PM
#15
Rennlist Member
Tried to observe this yesterday on my way home, and today on my way into the office. Maybe I'm not replicating the shift timing the same, but didn't see a difference from standard to Sport and didn't notice any odd throttle blip in Sport from 1-2. Then again, i'm at 550 miles on the car, so i've not wound up on the tach passed 3750 yet. Maybe its irrelevant to have any kind of break in period for this particular car, but its always been my habit to not go too hard on the engine or transmission for the first 1K miles in a new car.