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Author Topic: How to: Stock ECU Launch control on ME7  (Read 61553 times)
Nosbeui
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« on: July 30, 2010, 08:33:45 AM »

So you want to launch like the cool Subaru/Evo kids? As it turns out we can! And it's pretty easy. It works like this.. ME7 has a bulit in raised rev limit function which is unused by default. We set it up so the standard rev limit (NMAX) becomes the launch rpm and the raised limit becomes the normal limiter. It's controlled by VNMX so that as long as the car is below 1.25 km/h the launch control limit is used. Above 1.25 km/h the raised limit aka the new normal limit is used.

Here are the maps I modify including their M-Box addresses

CWNMAXMD (8-bit) Codeword Drehzahlbegrenzung Set to 1

VNMX             (1157E)     The vehicle speed for activating the raised (normal) rev limit. We set this as low at it goes (1.25 km/h) so the launch control shuts off as soon as you start moving off the line.
DNMAXH         (16304)     This is the RPM above rev limit when the fuel cut comes on. Tweaking this helps make more boost on the limiter. I use 50 RPM  (Keep in mind the maximum RPM limit is NMAXOG + DNMAXH)      
ITNMXH          (16308)     Dwell time under lower limit before activating the upper limit. We set this to 0 seconds
NMAX             (1630A)     Ends up being the launch RPM. I've found 4500 RPM works well.
NMAXOG         (16312)     This is the raised RPM limit which becomes the standard limit. Mine is set at 7100 RPM
TMOTNMX       (16316)     Coolant temp for activating raised (normal) rev limit. We set this at -48 so that it can activate at any coolant temp.
TNMXH           (1631A)     This is the time duration of the raised (normal) rev limit. We set this at it's maximum value of 655.3500 seconds. I haven't had a problem yet with this and have been testing for months.

And here are the results! http://vimeo.com/14266421

Eventually the plan might be to make this into a self installing patch file like the Subaru guys use.

I just uploaded a Stock M-box with this code http://nefariousmotorsports.com/forum/index.php?topic=152.0

Additional IMPORTANT Info!

Be aware that when using this method of launch control there is a time limit of 10.9 minutes for driving above the launch RPM. Therefore I suggest you set this appropriately high, somewhere above your normal cruising range. After 10.9 minutes the throttle shuts off until the RPM falls below the launch RPM... This is a potentially hazardous condition so please be aware and implement this code at your own risk!

Additional additional info

Thanks to k0mpresd I've learned certain ECU's need the map CWNMAXMD (8-bit) Codeword Drehzahlbegrenzung (Codeword for RPM limiter) changed from 0 to 1

-Brandon

EDIT: Correction the map is DNMAXH not DNMAX
« Last Edit: April 28, 2011, 11:05:34 AM by Nosbeui » Logged
elRey
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« Reply #1 on: July 31, 2010, 09:44:12 PM »

Great info. Can't wait to try this out.

On a similar, but different subject.... is there a way to cure/reduce rev hang when switching gears?
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NOTORIOUS VR
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« Reply #2 on: August 02, 2010, 11:13:12 AM »

wow... amazing work man!
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lukeag25
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« Reply #3 on: August 04, 2010, 10:42:33 AM »

Nice work! Thanks for sharing
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robin
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« Reply #4 on: August 04, 2010, 04:43:45 PM »

what's the longest you've cruised for with that active? I kept having problems with bumping the secondary limit on 3hr+ drives.
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k0mpresd
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« Reply #5 on: August 06, 2010, 09:08:11 AM »

can someone help me locate vnmx? please?  Smiley

edit: i found it. 11afc it looks like.

edit again: is vnmx 8 or 16 bit? im assuming 8.
« Last Edit: August 06, 2010, 09:37:15 AM by k0mpresd » Logged
Nosbeui
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« Reply #6 on: August 06, 2010, 08:23:50 PM »

what's the longest you've cruised for with that active? I kept having problems with bumping the secondary limit on 3hr+ drives.
I haven't had any trouble with it set at 4500 RPM. You'd have to be cruising at some really high speeds for about 11 minutes. Just curious what happens when you exceed the time limit? I'd assume the ECU cuts fuel and spark until the RPM is below the raised limit.

can someone help me locate vnmx? please?  Smiley

edit: i found it. 11afc it looks like.

edit again: is vnmx 8 or 16 bit? im assuming 8.

Yep its 8 bit.
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k0mpresd
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« Reply #7 on: August 06, 2010, 09:19:23 PM »

this is what i came up with, though im not sure its 100% correct, and i still dont know about the 2nd to last value.

4b0 906 018ch

Code:
vnmx 11afc 8bit 1x1 1.25 factor
dnmax 16494 16bit 1x1 .25 factor
itnmxh 16498 16bit 1x1 .01 factor
nmax 1649a 16bit 1x1 .25 factor
nmaxog 164a2 16bit 1x1 .25 factor
tmotnmx ????? 8bit 1x1 .75 factor
tnmxh 164a6 (?????) 16bit 1x1 .01 factor
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Nosbeui
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« Reply #8 on: August 07, 2010, 10:44:38 AM »

this is what i came up with, though im not sure its 100% correct, and i still dont know about the 2nd to last value.

4b0 906 018ch

Code:
vnmx 11afc 8bit 1x1 1.25 factor
dnmax 16494 16bit 1x1 .25 factor
itnmxh 16498 16bit 1x1 .01 factor
nmax 1649a 16bit 1x1 .25 factor
nmaxog 164a2 16bit 1x1 .25 factor
tmotnmx ????? 8bit 1x1 .75 factor
tnmxh 164a6 (?????) 16bit 1x1 .01 factor

Here is what I came up with for 4B0 906 018 CH

VNMX        11AFB   8bit
DNMAXH     16494 16bit
ITNMXH     16498  16bit
NMAX        1649A  16bit
NMAXOG    164A2  16bit
TMOTNMX  1F9EA   8bit
TNMXH      164A6  16bit

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k0mpresd
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« Reply #9 on: August 07, 2010, 10:55:36 AM »

thank you !!
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k0mpresd
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« Reply #10 on: August 07, 2010, 11:13:04 AM »

i set the limiter to 2500 (10000 in decimal) and the car still revs as freely as normal. no 2500 limiter. me = Huh lol.
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k0mpresd
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« Reply #11 on: August 07, 2010, 05:48:28 PM »

ok. so this does not work for me. the only way i get a 2500 limiter is if i set all 3 limiters to 2500. its either all or nothing. i tried every combination i could think of using a lower and higher limiter.
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k0mpresd
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« Reply #12 on: August 10, 2010, 08:02:30 AM »

working:

http://www.youtube.com/watch?v=nDHxPhNPE8s
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Nosbeui
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« Reply #13 on: August 10, 2010, 08:07:18 AM »

What ended up being the issue?

I would try DNMAXH set to 0 as I don't feel it's even hitting the fuel cut
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k0mpresd
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« Reply #14 on: August 10, 2010, 08:36:15 AM »

a bit at 11aeb. in my file its set to 00. my friend was looking through an rs4 file and said that it was set to 01 in that file. he said try setting it to 01. im not sure how he came to that conclusion but it worked.
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