Bucking while accelerating - DCT?

[DallasLife345M]

Originally Posted by Vader97

Hey I just picked up a DCT F83 M4. Just wanted to know if anyone else experiences jerkiness or bucking when in Sport+ in first gear. It felt like I was learning how to drive for the first time lmao

Yeah, this is normal. I keep mine in Sport around town and save Sport+ for highway and spirited driving.

[omaralt]

Happens to me sometimes and I have a 6 speed. You'll learn it and get better

[jmg]

Sport + is notorious for that. Both my '16 M3 and my '18 M3 CS do that. I prefer Sport for the track and street and Sport + for rare occasions.

[Vader97]

Originally Posted by jmg

Sport + is notorious for that. Both my '16 M3 and my '18 M3 CS do that. I prefer Sport for the track and street and Sport + for rare occasions.

Does sport mode still produce an aggressive sound like sport+

[Vader97]

Originally Posted by cartOC

A car with twin turbos in a more aggressively mapped throttle setting will do that. I'm not really sure what you expected, there's about 100 other threads you could've honestly looked through that extensively talk about this. It's an automatic transmission that acts like a manual transmission, it's not going to be the smoothest experience in sport plus if you don't have good foot control.

It's my first DCT car so I didn't know how to feather my way into it lol

[Vader97]

Originally Posted by weavingtraffic

Yes.. I thought it was a misfire or something was wrong with my car. Hahahaha I'm so glad I'm not the only one. First DCT car and I got it on Friday. So still a bit in shock, but I guess it's normal since you have the same feeling.

I looked dumb as hell when it rocked my head back and forth like three times LMAO

[jmg]

Originally Posted by Vader97

Does sport mode still produce an aggressive sound like sport+

Yes, flaps are all open in Sport and Sport+.

[N1rve]

Originally Posted by Vader97

Does sport mode still produce an aggressive sound like sport+

Yessir! Main difference is in Sport+ the turbos are kept spooled up.

[weavingtraffic]

Originally Posted by Vader97

I looked dumb as hell when it rocked my head back and forth like three times LMAO

BAHAHAHAHA. Thats awesome. I see you're in Jersey. Theres a thread with a whatsapp group for tri-state cruises/meetups. Just joined it and would recommend it! Friendly guys in there.

https://f80.bimmerpost.com/forums/sh....php?t=1526298

[Jim B]

Originally Posted by omaralt

Happens to me sometimes and I have a 6 speed. You'll learn it and get better

Same here on my 2015 M4.

[jmg]

PROBLEM SOLVED!

Just wanted to update my experience with this.

I noticed that when I changed my seating position to my track settings (closer to the pedals, more upright, full side bolsters etc) the car stopped lurching in Sport+.

I think this helps confirm that it's not the car itself that is lurching, it is the g-forces throwing our bodies back causing our feet to partially release the accelerator causing the car to suddenly decelerate. The deceleration causes our bodies to shift slightly forward and therefore restoring some pressure to the accelerator which starts an osculating chain reaction of acceleration and deceleration: the lurching.

Try it.

With my seat in the proper position I cannot get the car to lurch no matter the throttle input.

While the seating position I learned in High School of leaning back for that gangsta lean while cruising the boulevard checking out the honeys is comfortable and looks ridiculous now at my age, it's not the best for driving high performance vehicles with lots of power and a sensitive accelerator.


For those who don't already know:

Sit close enough that your knees are bent at rest and full application of the accelerator, brake, or clutch does not quite reach full extension. Your knee should still have an angle at full application of any of the pedals and should never be locked straight. This not only helps reduce injury in an accident (a locked knee will likely get significantly more damaged than a bent knee, but ensures that you can have full brakes when needed.

[Sir Loin]

Originally Posted by jmg

PROBLEM SOLVED!

Just wanted to update my experience with this.

I noticed that when I changed my seating position to my track settings (closer to the pedals, more upright, full side bolsters etc) the car stopped lurching in Sport+.

I think this helps confirm that it's not the car itself that is lurching, it is the g-forces throwing our bodies back causing our feet to partially release the accelerator causing the car to suddenly decelerate. The deceleration causes our bodies to shift slightly forward and therefore restoring some pressure to the accelerator which starts an osculating chain reaction of acceleration and deceleration: the lurching.

Try it.

With my seat in the proper position I cannot get the car to lurch no matter the throttle input.

While the seating position I learned in High School of leaning back for that gangsta lean while cruising the boulevard checking out the honeys is comfortable and looks ridiculous now at my age, it's not the best for driving high performance vehicles with lots of power and a sensitive accelerator.


For those who don't already know:

Sit close enough that your knees are bent at rest and full application of the accelerator, brake, or clutch does not quite reach full extension. Your knee should still have an angle at full application of any of the pedals and should never be locked straight. This not only helps reduce injury in an accident (a locked knee will likely get significantly more damaged than a bent knee, but ensures that you can have full brakes when needed.

^^^^^ THIS!

I posted here back in 2017 to explain what causes the problem and people didn't believe.

https://f80.bimmerpost.com/forums/sh...&postcount=246

Originally Posted by Sir Loin

This was very common on E46 M3 with SMG. It is usually user error. One way to fix it is move your seat closer so you can firmly plant you foot on the gas pedal when you accelerate. The problem is if you sit too far back, when you hit the gas pedal, the car's acceleration pushes you back in to your seat, and dragging your foot off the gas pedal. When that happens, the car decelerates, makes your body lung forward, bringing your foot forward and pushing the gas pedal again to accelerate. Rinse and repeat.

[jmg]

Originally Posted by Sir Loin

^^^^^ THIS!

I posted here back in 2017 to explain what causes the problem and people didn't believe.

https://f80.bimmerpost.com/forums/sh...;postcount=246

I'm now a believer!!

[Beemerm3]

today i was bucking in 2nd gear trying to power slide. I was in mdm mode and it was bucking on me. dam . last time it was 1st gear power slide that has bucking and now 2nd gear on mdm. not sure why though haha maybe dsc off would be nice.

[Mrm4sw49r]

Originally Posted by X2Board

My E90 did the same thing. Sometimes so badly, it made me look like a novice stick driver with a touchy clutch.

Lol yea I know

[Andrew30azs]

Hi guys

Just did diagnose on my dct after clunking noise on first two gears ( downshift ) And The stop where I did that diagnose said The transmission has a massive play under load And need to be replaced . Its any chance to gts flash could fix that problem ?

[sicck_m4]

Originally Posted by MWS55

When I have M Engine Dynamics set to Sport Plus and Drivelogic set to S3, the car bucks under heavy acceleration. Anyone else?

Under heavy acceleration it's smooth. When I feather the gas on 1st gear it starts to buck similar to a manual without enough throttle letting of the clutch.

[AlejoEvo]

Originally Posted by jmg

[SIZE="5"]PROBLEM SOLVED![/SIZE]

Just wanted to update my experience with this.

I noticed that when I changed my seating position to my track settings (closer to the pedals, more upright, full side bolsters etc) the car stopped lurching in Sport+.

I think this helps confirm that it's not the car itself that is lurching, it is the g-forces throwing our bodies back causing our feet to partially release the accelerator causing the car to suddenly decelerate. The deceleration causes our bodies to shift slightly forward and therefore restoring some pressure to the accelerator which starts an osculating chain reaction of acceleration and deceleration: the lurching.

Try it.

With my seat in the proper position I cannot get the car to lurch no matter the throttle input.

While the seating position I learned in High School of leaning back for that gangsta lean while cruising the boulevard checking out the honeys is comfortable and looks ridiculous now at my age, it's not the best for driving high performance vehicles with lots of power and a sensitive accelerator.


For those who don't already know:

Sit close enough that your knees are bent at rest and full application of the accelerator, brake, or clutch does not quite reach full extension. Your knee should still have an angle at full application of any of the pedals and should never be locked straight. This not only helps reduce injury in an accident (a locked knee will likely get significantly more damaged than a bent knee, but ensures that you can have full brakes when needed.

This is something people take as a joke. Seating is important in racing, don't matter if it is drag, some kind of circuit or even spirited driving on Sundays.

Glad you found solution to your problem.

[mdharper007]

Bought my car about 3 months ago, first vehicle purchase ever, only driven family handmedowns (think now 17yr old F150) for the past 15yrs. Third day I was driving it, I thought I'd show off my 'new' 3yr old car with some off the line red light acceleration, ended up jerking my way through the intersection.

It was an amazingly humbling experience as I learned to respect the vehicle. Completely agree with the thread and how important it is to learn the car. Still learning and loving it.

[Pat M4]

I was chasing a misfire , bucking , lack of power for a few weeks throwing 1000s in parts at my car(many sets of oem and NGK packs and plugs). Turns out the intercooler had an internal leak causing the coolant to go into the combustion chamber just enough to throw a drivetrain mal and cel if i really hit the gas. That will cause misfires at random. Check your intercooler resivour, if you have to fill it often, then you have a leak! Wanted to share

[F80dreams]

Originally Posted by mdharper007

Bought my car about 3 months ago, first vehicle purchase ever, only driven family handmedowns (think now 17yr old F150) for the past 15yrs. Third day I was driving it, I thought I'd show off my 'new' 3yr old car with some off the line red light acceleration, ended up jerking my way through the intersection.

It was an amazingly humbling experience as I learned to respect the vehicle. Completely agree with the thread and how important it is to learn the car. Still learning and loving it.

Lol i did the same on one of my first drives.

[i.is.m4cs]

Originally Posted by jmg

PROBLEM SOLVED!

Just wanted to update my experience with this.

I noticed that when I changed my seating position to my track settings (closer to the pedals, more upright, full side bolsters etc) the car stopped lurching in Sport+.

I think this helps confirm that it's not the car itself that is lurching, it is the g-forces throwing our bodies back causing our feet to partially release the accelerator causing the car to suddenly decelerate. The deceleration causes our bodies to shift slightly forward and therefore restoring some pressure to the accelerator which starts an osculating chain reaction of acceleration and deceleration: the lurching.

Try it.

With my seat in the proper position I cannot get the car to lurch no matter the throttle input.

While the seating position I learned in High School of leaning back for that gangsta lean while cruising the boulevard checking out the honeys is comfortable and looks ridiculous now at my age, it's not the best for driving high performance vehicles with lots of power and a sensitive accelerator.


For those who don't already know:

Sit close enough that your knees are bent at rest and full application of the accelerator, brake, or clutch does not quite reach full extension. Your knee should still have an angle at full application of any of the pedals and should never be locked straight. This not only helps reduce injury in an accident (a locked knee will likely get significantly more damaged than a bent knee, but ensures that you can have full brakes when needed.

Dude!!!

My mechanic is going to kill me when I tell him this lol.

Thank you for sharing this.