Dct downshift...

///M Villain · 11-29-2014, 10:07 PM

So before I got my M4 back in June, I was driving a 2011 335is, it was a awesome car and I never had any problems or complaints about it. One thing I totally loved about the car was it's downshift from 5th, 4th, 3rd, and 2nd gear; it was a Dct, and it was always in sport mode.
The way it downshifted is a lot different than my F82, whenever I braked in my old car the engine would rev and you would feel resistances or drag as it declined in speed and gears.

Now my current car "F82" it's always in M1 with all settings in sport plus.
The difference between these two cars can be felt when I brake, so the engine revs sometimes about 70% depending on how I brake; but in 3rd and 2nd gear on deceleration the F82 has zero drag or resistances. Making for some of the most jerky braking around, and it's like the car just wants to keep going. I don't know if anyone else can relate to what I'm talking about, but I am wondering if there is a way to get that "downshift resistance" feeling in the F82.

MFL · 11-30-2014, 02:50 AM

What you're referring to is "Compression Braking".

Ranoz · 11-30-2014, 07:17 AM

I feel exactly what you want in my M4, but not in my n55 335i. But it is relatively smooth at downshift when I drive my friends F80 M3. I'm also looking forward someone can help to explain.

gthal · 11-30-2014, 07:39 AM

I'm not sure I understand completely.

The M does engine brake on downshifts... it has to and all cars would. My guess is the car is rev matching and smoothly downshifting in a way that you don't feel the engine compression as much... but it is absolutely there. If you downshift without braking, you can absolutely feel the compression resistance you are talking about.

I find braking and downshifting in the M4 to be SUPER smooth so when you say downshifting and braking are jerky I don't know that I have experienced that.

Maybe I'm misinterpreting your post?

Andrew115 · 11-30-2014, 08:03 AM

Maybe the taller gearing is throwing you off. Downshift at higher speed than you have in the past you will have greater engine breaking.

Steveo · 11-30-2014, 12:50 PM

I have mine set at gear shift setting 1 and find it smooth when changing down.
If it's at 2 or 3 then it is jerk city.....

CanAutM3 · 11-30-2014, 01:14 PM

What do you mean by M1

?

What DCT setting do you use ?

crashtestdummy81 · 11-30-2014, 01:25 PM

You may be noticing a lack of engine braking due to being in sport+.
In sport/sport+ the turbo anti lag is active. From what I have read this work by having some of the cylinders still firing to generate enough exhaust to keep the turbo's speed up, this would be more than enough to overcome the engine compression braking.

Richy Rich · 11-30-2014, 03:01 PM

Quote:

Originally Posted by CanAutM3

What do you mean by M1

?

What DCT setting do you use ?

M1 is manual mode with the softest shift speed.

///M Villain · 11-30-2014, 05:10 PM

Quote:

Originally Posted by CanAutM3

What do you mean by M1

?

What DCT setting do you use ?

M1/M2 mode on the car is a preset button on the steering wheel, that you can customize in idrive menu. My M1 button is set to sport plus for all settings available.

///M Villain · 11-30-2014, 05:22 PM

Quote:

Originally Posted by crashtestdummy81

You may be noticing a lack of engine braking due to being in sport+.
In sport/sport+ the turbo anti lag is active. From what I have read this work by having some of the cylinders still firing to generate enough exhaust to keep the turbo's speed up, this would be more than enough to overcome the engine compression braking.

I did notice something different today, I did the cable unplug trick on my exhaust with valves fully open. While driving around I noticed a difference in dct downshifting and it felt like the car was slowing down with little braking applied. Also noticed if you pump the brakes rapidly a few times the car would downshift. Was doing about 50 to 52 mph in 4th gear, pumped the brakes rapidly and the car would drop down into 3rd gear over and over @ about 48/49 mph.

CanAutM3 · 11-30-2014, 11:06 PM

Quote:

Originally Posted by Richy Rich

M1 is manual mode with the softest shift speed.

Nope, not M1. What you refer to is S1

.

CanAutM3 · 11-30-2014, 11:08 PM

Quote:

Originally Posted by stickem601

M1/M2 mode on the car is a preset button on the steering wheel, that you can customize in idrive menu. My M1 button is set to sport plus for all settings available.

It wasn't obvious in your OP, that is why I asked.

However, that still doesn't answer what DCT Drivelogic mode you use ?

Richy Rich · 11-30-2014, 11:28 PM

Quote:

Originally Posted by CanAutM3

Nope, not M1. What you refer to is S1

.

Shows how much I pay attention to my dashboard when I'm in manual mode, lol.

///M Villain · 12-01-2014, 01:09 AM

Quote:

Originally Posted by CanAutM3

It wasn't obvious in your OP, that is why I asked.

However, that still doesn't answer what DCT Drivelogic mode you use ?

It's always set in D3

11-29-2014, 10:07 PM	#1
///M Villain Second Lieutenant 91 Rep 258 Posts Drives: Bmw M4 Join Date: Jul 2014 Location: Atlanta, Ga. iTrader: (1)	Dct downshift... So before I got my M4 back in June, I was driving a 2011 335is, it was a awesome car and I never had any problems or complaints about it. One thing I totally loved about the car was it's downshift from 5th, 4th, 3rd, and 2nd gear; it was a Dct, and it was always in sport mode. The way it downshifted is a lot different than my F82, whenever I braked in my old car the engine would rev and you would feel resistances or drag as it declined in speed and gears. Now my current car "F82" it's always in M1 with all settings in sport plus. The difference between these two cars can be felt when I brake, so the engine revs sometimes about 70% depending on how I brake; but in 3rd and 2nd gear on deceleration the F82 has zero drag or resistances. Making for some of the most jerky braking around, and it's like the car just wants to keep going. I don't know if anyone else can relate to what I'm talking about, but I am wondering if there is a way to get that "downshift resistance" feeling in the F82. Last edited by ///M Villain; 11-29-2014 at 10:44 PM..
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11-30-2014, 02:50 AM	#2
MFL Major 174 Rep 1,246 Posts Drives: E92 M3 Join Date: Sep 2013 Location: Bellevue, WA iTrader: (3) Garage List 2010 BMW M3 [9.00]	What you're referring to is "Compression Braking".
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11-30-2014, 07:17 AM	#3
Ranoz Private First Class 6 Rep 133 Posts Drives: M4 DSCLOL Join Date: Dec 2012 Location: Melbourne iTrader: (0)	I feel exactly what you want in my M4, but not in my n55 335i. But it is relatively smooth at downshift when I drive my friends F80 M3. I'm also looking forward someone can help to explain. __________________ JB4 \| Fie Cattless DP\| Vorsteiner Diffuser \| Black Grill \| LED Parking Light \| 15% Tint \| M Spoiler \| Black Side Grill \| LED Number Plate Light \| M Floor Mat \| CF Knob \| CF Centre Console Trim \| Handbrake Grip with Alcantara \| ADV1 5.0v1cs 20"
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11-30-2014, 07:39 AM	#4
gthal Major General 1904 Rep 5,678 Posts Drives: 2018 340i xDrive Join Date: Jul 2007 Location: Canada iTrader: (2)	I'm not sure I understand completely. The M does engine brake on downshifts... it has to and all cars would. My guess is the car is rev matching and smoothly downshifting in a way that you don't feel the engine compression as much... but it is absolutely there. If you downshift without braking, you can absolutely feel the compression resistance you are talking about. I find braking and downshifting in the M4 to be SUPER smooth so when you say downshifting and braking are jerky I don't know that I have experienced that. Maybe I'm misinterpreting your post? __________________ 2020 X3 M40i \| Black \| Current DD 2020 C8 Corvette \| Z51 \| Torch Red ... built and waiting for delivery 2016 M2 \| Long Beach Blue \| 6MT 2015 M4 \| Austin Yellow \| DCT 2012 MB C63AMG \| 2011 E92 M3 \| 2010 E92 M3
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11-30-2014, 08:03 AM	#5
Andrew115 Major 328 Rep 1,450 Posts Drives: Silver Bullet Join Date: May 2013 Location: Charlotte NC iTrader: (0)	Maybe the taller gearing is throwing you off. Downshift at higher speed than you have in the past you will have greater engine breaking.
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11-30-2014, 12:50 PM	#6
Steveo Captain 152 Rep 706 Posts Drives: M4 Join Date: May 2009 Location: Earth iTrader: (0)	I have mine set at gear shift setting 1 and find it smooth when changing down. If it's at 2 or 3 then it is jerk city.....
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11-30-2014, 01:14 PM	#7
CanAutM3 General 21117 Rep 20,741 Posts Drives: 2021 911 turbo Join Date: Jan 2012 Location: Montreal iTrader: (1) Garage List 2022 Audi RS6 [10.00] 2021 Porsche 911 turbo [10.00]	What do you mean by M1 ? What DCT setting do you use ?
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11-30-2014, 01:25 PM	#8
crashtestdummy81 Private First Class 25 Rep 102 Posts Drives: YMB F83 Join Date: Jul 2014 Location: UK iTrader: (0)	You may be noticing a lack of engine braking due to being in sport+. In sport/sport+ the turbo anti lag is active. From what I have read this work by having some of the cylinders still firing to generate enough exhaust to keep the turbo's speed up, this would be more than enough to overcome the engine compression braking.
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