Coding out Dynamic Brake Control (DBC)

TomK

TomK

Senior member
 West London
I find the z4m to be a pretty accomplished car on track with some mods however one thing that has always bugged me is the inconsistency that can occur with the brake pedal in certain situations.
It comes as a result of DBC, you can read about how it works here, suffice to say it can be difficult to modulate the brake when coming off the throttle very quickly.
http://www.bmw.com.kh/asia/en/insights/technology/technology_guide/articles/dynamic_brake_control.html?source=index&article=dynamic_brake_control
I've looked around on the web and haven't been able to find any one who has removed it on the Z4M, so I thought I'd have a go myself. Digging around it turns out our ecu is closely related to some of the newer e6/8x models and there in lay the answers.
The function you need to set to not active is BB_RAB found in the MK60 ecu.
That's it :) A very nice improvement on initial tests, pedal feel consistent :) I can update in a few weeks after Donnington.
If you wish you can also disable hill start assist which is HSA and also the automatic brake disk dry function for when it is wet by setting TB_BDD to not active.
 
Nice work. Given that you've now turned it off, do you think it ever came into play during "spirited" road driving?

I had assumed so, but it's hard to tell because the Z4M brakes are a bit over-servoed.
 
MrPT said:
Nice work. Given that you've now turned it off, do you think it ever came into play during "spirited" road driving?

I had assumed so, but it's hard to tell because the Z4M brakes are a bit over-servoed.
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No I don't really think it does. It takes extreme inputs to activate the system and if something you did on the road required it you'd probably be better off with it tbh. On track though in certain situations it can be bloody annoying so I'm keen to see how it goes next time out.
 
I think I had issues with this... I just put it down to a characteristic, what activates it just a hard stomp after WOT?b I triggered it a few times but couldn't always replicate it?
 
bradz said:
I think I had issues with this... I just put it down to a characteristic, what activates it just a hard stomp after WOT?b I triggered it a few times but couldn't always replicate it?
Click to expand...

I can trigger mine if you come off the accelerator quickly and touch the brake, the DBC primes the system for an emergency stop
 
Interesting :thumbsup: what are you using for coding? I really need to pull my finger out in the coding front!
 
It will activate with road driving, simply touching the brake after closing a WOT is enough.

Well done Tom, I hope this works as you suspect.

RedUn said:
Interesting :thumbsup: what are you using for coding? I really need to pull my finger out in the coding front!
Click to expand...

Me too, I’ve a code reader but no capacity to alter code at present. I’m very interested in this mod, so it might sway me to invest...
 
BMWZ4MC said:
RedUn said:
Interesting :thumbsup: what are you using for coding? I really need to pull my finger out in the coding front!
Click to expand...
Me too, I’ve a code reader but no capacity to alter code at present. I’m very interested in this mod, so it might sway me to invest...
Click to expand...
You'll need ncs expert to code this, available for £20 or so with the cable and various software (ncs/inpa/dis/tis etc). Whilst it can be a bit tricky setting the software up, once you know what you are doing most coding jobs take no more than a couple of mins. This DBC is found in the same module as the 'M'Track' mode previously discussed so you can do both whilst you are there. Lot's of interesting things in that module!
If you need any help with it drop me a line.
 
Cheers Tom :thumbsup: Any recommendation re which software to choose when purchasing?

I’m not too fussed about M Track Mode, I’m happy with the DSC Off setting :driving:

I suppose it’s good to know where it is though, in case one day I become a vegetarian :P :D
 
I think forum rules dictate that I'm unable to link anything directly but ebay is your friend here.
Mine I picked up from Bmcables (bcables) some time ago and I don't think are any longer in business so you'll have no support, however they seem to be still selling them on there. From a brief look the DJWW package looks good but is more expensive.

The M-track mode is worth having I'd say, it get's very little use but is nice to have.
 
Thanks for this Tom,

After driving the car today after its winter hibernation... Its getting coded out tomorrow, certainly felt it when trying to bed in the new brakes.

I had a good opportunity to test out M Track mode today - I'm a big fan, on a damp greasy road, allows just enough slip for you to feel alive without facing the wrong way, the stock TC is far too tight IMHO

Adam
 
bradz said:
Thanks for this Tom,

After driving the car today after its winter hibernation... Its getting coded out tomorrow, certainly felt it when trying to bed in the new brakes.

I had a good opportunity to test out M Track mode today - I'm a big fan, on a damp greasy road, allows just enough slip for you to feel alive without facing the wrong way, the stock TC is far too tight IMHO

Adam
Click to expand...

Oh cool, let us know what you think. I've only had the opportunity to drive it about 5 miles since removing it and won't get to test again until Donnington.
I'm a bit pissed now that I haven't looked at this sooner as it's been one of the few annoyances in the car since I've had it, so easy to remove, I was considering pulling the abs fuse for a while to get rid of it. I'd looked but just assumed it wasn't possible as had heard no mention of people being able to get rid of it.
Agree about m-track, it is a decent sized safety net in challenging conditions, the standard TC is not really usable if trying to push on at all.
That said it is a lot better than the TC used in the e46m3, that really is bad, but that's hobbled by an earlier ecu version than us. As a result though they didn't get dumped with this DBC nonsense!


Eta, interestingly you also have access to what looks to be all of the parameters that govern the TC intervention in this ecu. It's complicated to figure out what it all means, not least that it's in German and my ncs dummy is ancient, but interesting all the same.
 
I want to get this coded out on mine, and M track mode added.
Anyone in the South East recommended to do it?
 
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