DCT...DTC power loss??

[Gnip Gnop]

So I was driving home from work today and noticed something unusual.

I have an n55 dct (7 speed) and I was in m5, and had sport mode on.

I gave it a small bit of throttle, and hit the DTC button, and I experienced a loss of power. It felt exactly what it would feel like if you turned sport mode off. The throttle response was reduced greatly compared to what it was before. Then I gave it the same amount of throttle while having DTC ENGAGED, turned DTC off, and I gained my power/throttle response back.

So does having DTC engaged, or everything completly off did it as well, reduce power output?

[BimmerEnthusiast99]

My guess would be doing all of that at the same time caused the system to "hiccup" perhaps.

Does it do it every time under the same circumstances? Maybe it's one of those things where the patient says, "doctor, it hurts when I do this;" and the doctor says, "well, then don't do that."

[Gnip Gnop]

Originally Posted by BimmerEnthusiast99

My guess would be doing all of that at the same time caused the system to "hiccup" perhaps.

Does it do it every time under the same circumstances? Maybe it's one of those things where the patient says, "doctor, it hurts when I do this;" and the doctor says, "well, then don't do that."

I have never noticed it, because whenever I hit dtc, I am at a stop. So I guess the only reason I noticed is because the car was in boost. I even heard the turbo push less psi.

[Gnip Gnop]

Can anyone else help out on this issue? Anyone experience something similar?

[Sinister Crayon]

I actually think it's normal. I don't know for sure but I have a suspicion that BMW tunes the sport mode with DTC on to be more aggressive than with it off precisely because it's so easy to lose traction.

For the record, I actually noticed this exact same behaviour in my car in the last couple of weeks, but like you I never really thought about it before because I don't remember ever turning DTC off while actually driving.

I will note that out of curiosity I tried on a straight empty stretch of road accelerating to 40mph, holding the throttle and then trying DTC on/off and sport mode on/off. The sport mode off definitely made much more of a difference than the DTC off, but yes there's a definite feeling of less throttle response. Try turning DTC off and then sport mode off and you'll notice a "two step" feeling.

I have a feeling that because the DCT has a shorter geared rear than the 6MT it's probably far too easy to break traction under hard acceleration in the DCT than the 6MT. BMW probably made the choice to slightly detune the throttle response so that you'll actually still be able to control it properly instead of turning your expensive RFT's into foul smelling smoke.

[Gnip Gnop]

Originally Posted by Sinister Crayon

I actually think it's normal. I don't know for sure but I have a suspicion that BMW tunes the sport mode with DTC on to be more aggressive than with it off precisely because it's so easy to lose traction.

For the record, I actually noticed this exact same behaviour in my car in the last couple of weeks, but like you I never really thought about it before because I don't remember ever turning DTC off while actually driving.

I will note that out of curiosity I tried on a straight empty stretch of road accelerating to 40mph, holding the throttle and then trying DTC on/off and sport mode on/off. The sport mode off definitely made much more of a difference than the DTC off, but yes there's a definite feeling of less throttle response. Try turning DTC off and then sport mode off and you'll notice a "two step" feeling.

I have a feeling that because the DCT has a shorter geared rear than the 6MT it's probably far too easy to break traction under hard acceleration in the DCT than the 6MT. BMW probably made the choice to slightly detune the throttle response so that you'll actually still be able to control it properly instead of turning your expensive RFT's into foul smelling smoke.

Thanks for the great response. That makes sense, I'm glad to hear its not only my car having this issue.

[Johnny135i.za]

Thread revival...

I've also noticed this in my 2010 n55 DCT.

Was cruising along a straight stretch of road at a steady speed of about 100kph (60mph) with Sport Mode On and DTC on.when pressing the dtc button to turn it off I could immediately feel the car pulling slightly stronger.and the throttle felt a little bit more responsive.

With Sport Mode off this difference in power is not present when pushing the DTC button!this only happens when driving with Sport Mode On.

I did this a few times with the same result.glad to see its not only my car, maybe just these cars that's programmed this way...

Thought it might be related to my PPK2 software installed.

[Andrewcoja]

DTC changes the throttle map.

[Johnny135i.za]

Originally Posted by Andrewcoja

DTC changes the throttle map.

Undestood yes but it's rather strange that the throttle gets less sensitive when DTC is deactivated!one would assume when one presses the DTC button to activate it, it will be to have some fun hence giving the driver MORE throttle responsiveness.but BMW decided "screw that, let's take some of the fun away"...I guess it's a safety feature of some kind.so that the less talented drivers don't get themselves into too much trouble

[ShocknAwe]

Sounds like it's time for a tune!

[02rsxpilot]

I don't know what these OPs were talking about. I've turned DSC (might as well use the correct acronym) off mid-session on a race track and noticed zero change in throttle response, and I double-checked tonight on the street and also felt zero change. There is also nothing in the owner's manual about DSC affecting throttle mapping.

[Andrewcoja]

It's a very subtle change. Press your foot in a bit to accelerate and then press the DTC button without moving your foot. It will change the throttle response.

[3002 tii]

Originally Posted by 02rsxpilot

I don't know what these OPs were talking about. I've turned DSC (might as well use the correct acronym) off mid-session on a race track and noticed zero change in throttle response, and I double-checked tonight on the street and also felt zero change. There is also nothing in the owner's manual about DSC affecting throttle mapping.

x10 a lot of misleading info here. It's like saying the car feels faster after a car wash LOL

[Overpar56]

Originally Posted by 3002 tii

x10 a lot of misleading info here. It's like saying the car feels faster after a car wash LOL

Mine is. Less surface resistance.

[3002 tii]

Originally Posted by Overpar56

Mine is. Less surface resistance.

You need to measure before and after water fully drying, the weight differential is +/- 2mph on your trap speed.

[Miikahellsten]

Originally Posted by Gnip Gnop

So I was driving home from work today and noticed something unusual.

I have an n55 dct (7 speed) and I was in m5, and had sport mode on.

I gave it a small bit of throttle, and hit the DTC button, and I experienced a loss of power. It felt exactly what it would feel like if you turned sport mode off. The throttle response was reduced greatly compared to what it was before. Then I gave it the same amount of throttle while having DTC ENGAGED, turned DTC off, and I gained my power/throttle response back.

So does having DTC engaged, or everything completly off did it as well, reduce power output?

Hello. has this problem been solved? I have the same problem.

[Miikahellsten]

Originally Posted by Gnip Gnop

So I was driving home from work today and noticed something unusual.

I have an n55 dct (7 speed) and I was in m5, and had sport mode on.

I gave it a small bit of throttle, and hit the DTC button, and I experienced a loss of power. It felt exactly what it would feel like if you turned sport mode off. The throttle response was reduced greatly compared to what it was before. Then I gave it the same amount of throttle while having DTC ENGAGED, turned DTC off, and I gained my power/throttle response back.

So does having DTC engaged, or everything completly off did it as well, reduce power output?

Hello. has this problem been solved? I have the same problem.

[Miikahellsten]

I have this same broblem. When sport mode on and press dtc button the car loss power..i researched it and noticed that when the dtc is on then the boost pressure drops to 7.5 psi.��

[Esteban]

Originally Posted by Miikahellsten

Hello. has this problem been solved? I have the same problem.

Has been discussed before. Here are a couple of threads about it:

https://www.1addicts.com/forums/show....php?t=1046550

https://www.1addicts.com/forums/show....php?t=1243197

[BMWGuy4852]

I've never used the paddles, sport, DTC, or any other buttons. In this way, I never experience any problems! LOL

[Miikahellsten]

Originally Posted by Esteban

Has been discussed before. Here are a couple of threads about it:


https://www.1addicts.com/forums/show....php?t=1046550

https://www.1addicts.com/forums/show....php?t=1243197

Ok.thank you.I read these👍