Full throttle back firing during upshift...?
04-13-2017, 01:39 PM
#1
Full throttle back firing during upshift...?
2017 GS backfires during the upshift under full throttle.
Only happens in Sport or Track modes.
Is this "normal" due to the ignition cutting out for the upshift or should I have the dealer look at it...?
Thanx, Sarge
Only happens in Sport or Track modes.
Is this "normal" due to the ignition cutting out for the upshift or should I have the dealer look at it...?
Thanx, Sarge
04-13-2017, 04:54 PM
#5
Le Mans Master
Mine doesn't fully backfire, but it does pop. That's normal. So the M7 holds the RPM while you row the gear, the automatic cuts fuel/spark/whatever briefly to allow the clutches to apply. Different approaches.
As Higgs will mention, manual drivers already normally lift during shifts...
As Higgs will mention, manual drivers already normally lift during shifts...
Last edited by davepl; 04-15-2017 at 11:50 AM.
04-14-2017, 03:00 AM
#6
Melting Slicks
Yes. Its a nice pop. Sounds cool.
04-14-2017, 12:31 PM
#7
Team Owner
Member Since: Jan 2007
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Mine doesn't fully backfire, but it does pop. That's normal. Manual doesn't shift fast enough to need this feature, but the manual features no-lift-shift. So the M7 holds the RPM while you row the gear, the automatic cuts fuel/spark/whatever briefly to allow the clutches to apply. Different approaches.
04-14-2017, 11:32 PM
#9
Race Director
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it's not a backfire, it's spark cut for the modern clutched auto to shift properly.
a manual transmission wouldn't use this as the driver let's off the throttle and puts in the clutch when completing a shift thereby removing power application from the shift process.
a manual transmission wouldn't use this as the driver let's off the throttle and puts in the clutch when completing a shift thereby removing power application from the shift process.
04-15-2017, 11:50 AM
#10
Le Mans Master
You're spot on, except during no-lift-shifts, but that's different because there's no load on the transmissions when it's decoupled like that, whereas the automatic is still hydraulically coupled during shifts, so they need to limit rpm AND power.
Last edited by davepl; 04-15-2017 at 11:51 AM.