E9X M3 DCT can now get Torque limit bumped

doublespaces

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Oct 18, 2016
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MaxxECU sent me a link to their torque table TCU flash:

Product description
Requires you to send us a M3 E9x TCU for us to flash our custom firmware which increases the clutch pressures from 15.5bar to 17.5bar which therefore increases the transferred torque.
ONLY M3 E9x TCU

1-2 weeks delivery time
 

doublespaces

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It peaks at the same thing, but I don't know how all of the in between part scales.
 

azshantris

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Aug 27, 2019
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Is the TCU actually different in the M3 or is it just the flash? Sorry for my ignorance, I guess I could check realoem.
Having just completed my M3 GTS swap I wonder if this could be be beneficial. I've heard the "is" flash has always had the higher pressures?
I'm not at a power level high enough for this to really be a concern, yet. But its definitely cool info and something I could end up being interested in.
Wonder whatever happened with the potential xHP stuff 🤔
 

azshantris

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Aug 27, 2019
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2011 135i N55 DCT GTX1000
Is the TCU actually different in the M3 or is it just the flash? Sorry for my ignorance, I guess I could check realoem.
Having just completed my M3 GTS swap I wonder if this could be be beneficial. I've heard the "is" flash has always had the higher pressures?
I'm not at a power level high enough for this to really be a concern, yet. But its definitely cool info and something I could end up being interested in.
Wonder whatever happened with the potential xHP stuff 🤔
I looked and it appears to be the same physical unit listed all encompassing as part of the mechatronics.
 
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RSL

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Aug 11, 2017
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out Of interest what’s the clutch pressure on the 135/335’s?
 
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aus335iguy

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So, the one thing we may have over the M guys is line pressure. As @RSL said... it’d be interesting to see what an N54 with M flashed DCT does ... @LMB335is you may have logged this ?
 

RSL

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So, the one thing we may have over the M guys is line pressure. As @RSL said... it’d be interesting to see what an N54 with M flashed DCT does ... @LMB335is you may have logged this ?
I think Sbrach said there might be a check valve that limits clutch pressure to 18bar. If true and if in both trannies, max would be the same for both. As mentioned though, might be a difference in how things ramp, but I suspect it's clutch engagement time that bangs gears in MDCT rather than line/clutch pressure.

Sport off includes a clutch slip phase that is non-existent with Sport on. IIRC though, pressure is same/higher with sport off though.

I would be curious to see same tune logged on non-M and then MDCT with level 1 and then 6 to compare.
 

aus335iguy

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What I meant was that our TCU software seems to have a higher max line pressure. I’m assuming this given that people have logged above 17bar on ours and maxxecu is selling 17bar to M drivers.
 

RSL

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Right. E9x Ms might be able to also if they have tuning that can increase torque param fed to the TCU. There are also torque limits in the TCU, so not quite sure exactly what they're selling at this point lol I don't think pressure increases would be all that significant, at least not +1-2bar peak. Torque limits/gradients might be a different story.

They'd probably get more sales offering a simple defined FD change...
 

LMB335is

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So, the one thing we may have over the M guys is line pressure. As @RSL said... it’d be interesting to see what an N54 with M flashed DCT does ... @LMB335is you may have logged this ?

I haven't logged bar pressure per se but if torque actual value nm logged through MHD means anything, I'm am/was consistently over 900 nm on the GTS flash and 335is software.

Check that. After going through some old logs in datazap it looks like torque actual value nm is about 50-100 nm higher with the GTS flash.
 

Nisse Järnet

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Feb 4, 2018
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If you report the full 1023Nm to the M3 TCU youll get around 15.5 bar clutch pressure.
If you report the same to a 335 TCU youll get the full 17.5 bar, only difference is the TCU flash. (clutch pressure is mechanically limited to ~18 bar via a over pressure valve)
So with this sevice youll get the M3 TCU flashed with a custom file that will allow 17.5 bar pressure, just like a 335 TCU.
 
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