Power-cut/Bog on Launch Control 991.2 Targa 4 PDK
07-23-2021, 11:49 AM
#1
Instructor
Thread Starter
Power-cut/Bog on Launch Control 991.2 Targa 4 PDK
I have a 2019 991.2 Targa 4 and am frustrated with the lack of launch control reliability. I try to launch using the documented procedure (Sport+ and launch control pops up on dash) but when I get going I almost always get a major jolt (my head jolts forward) as if I dropped the clutch on a manual car. It also feels like a power cut for traction or something. I suspected it was worn tires, but have since replaced them with brand new PS4s and make sure they are warm every time too. Still an unsettling jolt. Should I suspect PDK clutch health is poor? I am the second owner, so part of me wonders if this car was abused in its early days...
07-23-2021, 11:57 AM
#3
RL Community Team
Rennlist Member
Rennlist Member
From a standstill, mash the gas pedal to the floor. Don't start launch control. Does the car just go, or do you get this abnormal power cut still?
Using launch control will largely the same feeling as just flooring it, just with a higher rpm burn on the clutches and like a tenth of a second faster 0-60. The power engagement should be liquid smooth either way.
Hard cuts to power will be TCS, misfire, or driver input such as lifting the throttle pedal sharply.
You can confirm TCS intervention by the blinking light on the dash (don't just turn it off, ffs). Misfire is very distinct, and you should be able to feel this under load in any gear if that's the case, and it should also be lighting up the CEL if it's happening more than once. Driver input is just that, driver input -- make sure your foot is on the floor.
Using launch control will largely the same feeling as just flooring it, just with a higher rpm burn on the clutches and like a tenth of a second faster 0-60. The power engagement should be liquid smooth either way.
Hard cuts to power will be TCS, misfire, or driver input such as lifting the throttle pedal sharply.
You can confirm TCS intervention by the blinking light on the dash (don't just turn it off, ffs). Misfire is very distinct, and you should be able to feel this under load in any gear if that's the case, and it should also be lighting up the CEL if it's happening more than once. Driver input is just that, driver input -- make sure your foot is on the floor.
Last edited by asellus; 07-23-2021 at 11:59 AM.
07-23-2021, 03:06 PM
#4
Three Wheelin'
How many seconds after you release the brake until the jolt hits?
07-23-2021, 03:09 PM
#5
Instructor
Thread Starter
Immediately, as soon as I let off the break the PDK engages and revs drop to idle level.
07-23-2021, 03:11 PM
#6
Three Wheelin'
Gotta be not keeping your accelerator foot mashed past the click down point. If the click down is released, launch disengages.
10-06-2021, 07:46 PM
#7
Instructor
Thread Starter
Update here: I am 99% certain the issues I've had with a "bog" in the past were indeed caused by my foot coming off the throttle even a micro-meter. Haven't had issues since nailing my foot to the floor each time. 
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10-06-2021, 08:39 PM
#8
Three Wheelin'
Thanks for following up.