2019 991.2 rev match bug (1st to 2nd)?
10-28-2018, 09:13 PM
#31
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.
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.
10-28-2018, 11:20 PM
#32
Burning Brakes
Thread Starter
I have noticed this also with my 2019 T today over 5000rpm from 1 to 2nd. Under hard acc. And shift from 1st to 2nd the car blips the rpm higher. Has anyone talked with the dealer and found this to actually incorrect behaviour or are we all under the impression that this is normal for all 911.2 manual cars?
10-29-2018, 01:43 AM
#33
Rennlist Member
Same here! Has happend to me many times in both my GTS’s I had. Kinda of annoying honestly. 1st gear then hit the clutch to shift into second and it revs up then drops once in second. Wasn’t a fan.
Last edited by Scottykenneth; 12-22-2018 at 05:52 AM.
10-29-2018, 07:01 PM
#35
Took my car into the dealer today and spoke with a SA about the blip from 1st to 2nd. They advised me that it’s completely normal as it help to create a smoother matched shift. I’m not completely convinced as it only does it between 1st and 2nd and no other gears. But I guess it makes sense
10-29-2018, 08:52 PM
#36
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.
10-29-2018, 11:12 PM
#37
Burning Brakes
Thread Starter
Took my car into the dealer today and spoke with a SA about the blip from 1st to 2nd. They advised me that it’s completely normal as it help to create a smoother matched shift. I’m not completely convinced as it only does it between 1st and 2nd and no other gears. But I guess it makes sense
I’m also skeptical about the claim of smoother shift. Rpm drops during an upshift. Unless you let the rpm drop below the rpm for 2nd gear, adding rpm only makes the shift less smooth. I also cannot think of a mechanical reason why it should work this way (other than getting closer to WOT shifts to maximize acceleration at the expense of smoothness and wear).
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10-30-2018, 11:36 AM
#38
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Just to clarify, what configuration has the auto-blip on the manual? Is it only on cars that have the Sport Chrono? Or is it in Sport mode on S & GTS models regardless of whether the car has the Sport Chrono? Basically, if a car is a S without Sport Chrono with it have the auto-blip in Sport mode?
10-30-2018, 10:02 PM
#39
991.2 S without Sport Chrono does not auto blip in Sport mode.
12-22-2018, 01:47 AM
#40
Rennlist Member
Add me to the list of 2019 Carrera T owners who are experiencing this with a manual transmission. Just got my car this week and after driving only 120 miles have witnessed the “throttle blip” on upshift from 1st to 2nd gear. I immediately assumed something was wrong such as a software bug as the issue occurred multiple times and just feels strange.
I agree that the problem seems to manifest itself when you rev out the engine and execute a faster and more agressive 1-2 gear change. Also seems to occur only in sport and sport plus modes.
Has as anyone gotten any clarity from their dealerships if this is normal and by design behavior for a manual transmission 991.2? I test drove a used 2018 Carrera T and don’t recall feeling this during the drive, so perhaps a change to the 2019 software?
Also, did anyone determine if the rev matching can be defeated by disabling PSM?
Sorry to bring this one back to life but it really is a bother and simply does not feel like natural behavior.
I agree that the problem seems to manifest itself when you rev out the engine and execute a faster and more agressive 1-2 gear change. Also seems to occur only in sport and sport plus modes.
Has as anyone gotten any clarity from their dealerships if this is normal and by design behavior for a manual transmission 991.2? I test drove a used 2018 Carrera T and don’t recall feeling this during the drive, so perhaps a change to the 2019 software?
Also, did anyone determine if the rev matching can be defeated by disabling PSM?
Sorry to bring this one back to life but it really is a bother and simply does not feel like natural behavior.
12-22-2018, 09:59 AM
#41
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If you turn off traction control it will disable rev-match...there is a lengthly thread about this with a lot of info if you get bored as there is not a solution (yet).
12-22-2018, 10:53 AM
#43
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12-22-2018, 10:56 PM
#44
Burning Brakes
Thread Starter
I didn’t persist. I kinda just gave up as my GT3 will be here soon enough. I’m hoping the GT3 manual won’t have this issue. We will see.
12-22-2018, 11:05 PM
#45
Rennlist Member
Sure sounds like multiple 991.2 manuals are seeing this behavior. So, I would assume it’s programed into the rev match software (by deign) on all cars and not just an isolated issue that only you and I are experiencing.
Also, given that it does not occur in normal mode or with PSM (Please Save Me) switched off, it’s clearly something in the software mapping. Congrats on the GT3. I believe the GT cars have an option to disable rev matching when wanted?
Also, given that it does not occur in normal mode or with PSM (Please Save Me) switched off, it’s clearly something in the software mapping. Congrats on the GT3. I believe the GT cars have an option to disable rev matching when wanted?