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      10-11-2017, 01:02 PM   #1
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Traction Mode problems

I've had my LCI for about 3 weeks. The traction (MDM) mode is fantastic for the burbles and pops. I've noticed intermittently that after pushing the button there is no change in the exhaust character and it seems to stay in comfort mode. At first it happened once every few days but today I had to turn traction on and off 4-5 times to get it to make sexy sounds. The traction light comes on and idrive shows the change but no exhaust change. Anyone else run into this problem?

I've also noticed a lag in the 1500-2000 RPM range in traction mode where the engine seems to hesitate before picking up again. Not like turbo lag but like its cutting ignition or something. Not sure if this is related. No CEL or anything else.
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      10-11-2017, 01:13 PM   #2
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Traction mode puts the throttle in comfort. If you have a manual you will notice it more. You may also be feeling the traction control since it is still aggressive even in MDM mode.
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      10-11-2017, 01:15 PM   #3
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Quote:
Originally Posted by David1 View Post
Traction mode puts the throttle in comfort. If you have a manual you will notice it more.
I'm reffering the exhaust note though. The way it's functioned for me is traction always burbles and pops on deceleration off throttle. Mine is occasionally staying in "comfort" exhaust mode and requires turning traction on and off to get it back to burble mode. The throttle sensitivity and auto-rev match function haven't changed, as expected.

With the lag, its under light acceleration, <50% throttle application, so I don't think its wheelspin or TC kicking in.
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      10-11-2017, 03:45 PM   #4
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Mine does not do it all the time either. It's dependent on rpm and how quick you let off. Mine (17) has more exhaust noise in sport plus than just in MDM mode.
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      10-11-2017, 07:09 PM   #5
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Firstly..

When you put it in MDM. It'll only make burbles and pops once the car is warmed up..
So if you put it in MDM on the cold start, it'll take a couple minutes of driving for the ECU to to make these over runs and burbles because one of the preliminary requirements is that the engine is warm enough (hits a specific temp.)
All BMW are programmed to not burble over 5,000 RPM.

Secondly, if you run it in MDM. Your throttle response is actually equivalent to sport..
Its more responsive than comfort but less than sports +

Thirdly, the stock valve are pretty crap, all the exhaust sound the same pretty much.
However, on sports+ I believe that over a specific RPM (I think 3,500) it is louder than comfort. But all else remains the same except comfort doesn't allow for engine braking.

Hope this clears up your questions!
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      10-11-2017, 07:47 PM   #6
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Quote:
Originally Posted by iQuiet View Post
Firstly..

When you put it in MDM. It'll only make burbles and pops once the car is warmed up..
So if you put it in MDM on the cold start, it'll take a couple minutes of driving for the ECU to to make these over runs and burbles because one of the preliminary requirements is that the engine is warm enough (hits a specific temp.)
All BMW are programmed to not burble over 5,000 RPM.

Secondly, if you run it in MDM. Your throttle response is actually equivalent to sport..
Its more responsive than comfort but less than sports +

Thirdly, the stock valve are pretty crap, all the exhaust sound the same pretty much.
However, on sports+ I believe that over a specific RPM (I think 3,500) it is louder than comfort. But all else remains the same except comfort doesn't allow for engine braking.

Hope this clears up your questions!
Awesome, that definitely makes sense as this happens most often when the engine is colder. Great info all around, appreciate it!
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      10-12-2017, 01:17 AM   #7
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Originally Posted by iQuiet View Post
But all else remains the same except comfort doesn't allow for engine braking.
Is this actually verified truth? Comfort does something non-standard to prevent lift-throttle engine braking? (What does it do, open the intake valves a bit to prevent building vacuum?)
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      10-12-2017, 01:47 AM   #8
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Quote:
Originally Posted by ZPrime View Post
Is this actually verified truth? Comfort does something non-standard to prevent lift-throttle engine braking? (What does it do, open the intake valves a bit to prevent building vacuum?)
I'm not sure the technical side of things, But I can assure you that it downshits (without engine rev matching) at a point when the gap between the revs don't have a large disparity causing a violent downshift.

So for example, on a standard manual, it'll wait till the engine speed is equivalent enough for you to downshift and instantly let out the clutch (aka to the point you shouldn't have been in that gear).

Something similar to this.
ECU Programmed.
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      10-12-2017, 02:24 AM   #9
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Quote:
Originally Posted by iQuiet View Post
I'm not sure the technical side of things, But I can assure you that it downshits (without engine rev matching) at a point when the gap between the revs don't have a large disparity causing a violent downshift.

So for example, on a standard manual, it'll wait till the engine speed is equivalent enough for you to downshift and instantly let out the clutch (aka to the point you shouldn't have been in that gear).

Something similar to this.
ECU Programmed.
I'm still waiting for my car to get here so I'm trying to understand this, I imagine it will be more obvious once I drive it, but...

So if I'm cruising in 4th doing ~40mph, and I push the clutch and shift to 2nd, while the car is in Comfort... are you saying it does not rev up the throttle? If I then release the clutch, it somehow "holds" that clutch release until the revs have dropped on their own?
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      10-12-2017, 05:40 AM   #10
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Quote:
Originally Posted by iQuiet View Post

Secondly, if you run it in MDM. Your throttle response is actually equivalent to sport..
Its more responsive than comfort but less than sports +
According to the technical chart, throttle response in MDM is in COMFORT and it does feel like it from personal experience.
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      10-12-2017, 02:39 PM   #11
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Quote:
Originally Posted by D CHOI View Post
According to the technical chart, throttle response in MDM is in COMFORT and it does feel like it from personal experience.
This is correct.
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      10-17-2017, 01:52 AM   #12
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If the EGT is too high the car won’t burble. And it doesn’t always burble. My car burbles in MDM and I mean quite violently just roughly 1-2 minutes off cold start.

Sometimes if you put it directly into MDM on over run from comfort it’ll take another throttle application to get it to burble. Normal behavior. You can’t expect a DME to change it’s fueling map half way through... that would be interesting coding challenge.

As for rev matching in comfort or MDM the rev match is much more tame so you have two options. Be slower on shift / timing of clutch engagement or blip the throttle yourself in addition or just go in sport or sport+.

I usually drive in MDM and I still rev match myself when I need to.

As for engine braking on comfort or sport. It’s definetly not as aggressive as in sport + but this is mainly for economy. Yes there’s still engine braking as in you’ll be slowing down.

But even then all BmWs now don’t have 100% engine braking due to turbo setup as well as ECU tuning
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      10-22-2017, 12:37 AM   #13
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Quote:
Originally Posted by iQuiet View Post
I'm not sure the technical side of things, But I can assure you that it downshits (without engine rev matching) at a point when the gap between the revs don't have a large disparity causing a violent downshift.

So for example, on a standard manual, it'll wait till the engine speed is equivalent enough for you to downshift and instantly let out the clutch (aka to the point you shouldn't have been in that gear).

Something similar to this.
ECU Programmed.
Yeah, so I have my car now and I have no clue WTF you're talking about. Whether it's in Comfort or Sport, the car certainly engine breaks just fine.

I did note that at very low revs (uner 2000 down to 1k) the braking effect does seem to be somewhat reduced, I haven't played enough to figure out if this changes between Sport and Comfort though.
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      10-22-2017, 06:54 PM   #14
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Quote:
Originally Posted by iQuiet View Post
When you put it in MDM. It'll only make burbles and pops once the car is warmed up..
Not true. All you have to do is put it in sport + and accelerate aggressively once. Put in in MDM after that and it will not only burble and pop. It will be the loudest pops you've ever heard. It sucks it only happens like that when the engines cold because it is violently loud and i love it. Try it if you don't believe me. And no you don't have to red line it or anything stupid like that. Just floor it to ~2500 in sport + in 2nd gear and let go of the accelerator. As soon as it makes the farting noise hit the traction button. It will BANG like crazy from then until the car warms up. Just play with the throttle.

Quote:
Originally Posted by iQuiet View Post
Secondly, if you run it in MDM. Your throttle response is actually equivalent to sport..
Its more responsive than comfort but less than sports +
Nope. In MDM throttle is the same as comfort.

Quote:
Originally Posted by iQuiet View Post
comfort doesn't allow for engine braking.
Yes it does...it's just delayed. Next time you downshift in comfort just wait a second before you drop the clutch and it will rev match. It's much slower than sport/sport + but it will do it.

Last edited by AndrewC1989; 10-23-2017 at 04:47 PM..
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      01-12-2018, 03:47 PM   #15
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What on earth Is MDM mode? Does the LCI have this? Id like more burbles if possible and this might appeal. How do you engage this mode?
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      01-12-2018, 03:57 PM   #16
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Quote:
Originally Posted by Maximoosh View Post
What on earth Is MDM mode? Does the LCI have this? Id like more burbles if possible and this might appeal. How do you engage this mode?
MDM mode = traction mode in our cars.

Turn it on by quick pressing the traction off button near your gear lever/shift knob. A long push of the button turns off all the nannies, "DSC Off" mode. Pops and burbles not as loud as traction mode.
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      01-13-2018, 05:31 PM   #17
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I bought the MPE and it cracks n pops alllllllll the time.

I am not sure when the stock flap even closed on my car. I think it was defective to tell you the truth. But a non issue now
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      01-18-2018, 10:32 PM   #18
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Quote:
Originally Posted by Maximoosh View Post
What on earth Is MDM mode? Does the LCI have this? Id like more burbles if possible and this might appeal. How do you engage this mode?

Press (not hold) the traction control button, and you'll see 'Traction' on dash, that's MDM
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