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Old 11-12-2012, 11:54 PM   #102
TerraPhantm
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Join Date: Feb 2008
Location: Mountain Top
Posts: 5,979
My Ride: 2005 M3 Coupe
I have been studying the MS45.1 tunes a little bit - mostly comparing ZHP and standard 330i software. I believe I've located the speed limiter and possibly the rev limiter.

Here are the binaries:
gone

I believe the speed limit is a 16-bit value stored at 5F44 (and repeats again at 5F46). I believe that this value equals speed * 0x7D.

On the 330i, the value at that location is 0x6480. 0x6480 / 0x7D = 0d205. 205km/h is just about 128mph.
The value for the ZHP at that location is 0x7A00, which ends up translating to 250kmh or ~155mph.

For RPM... from 60D4 to 6140 you have the following (ZHP and then 330i)

ZHP
Code:
1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 
1A F4 1A F4 1A F4 1A F4 1A F4 15 04 15 04 15 04 15 04 
1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 
1A F4 1A F4 1A F4 1A F4 1A F4 1A F4 1A F4 1A F4 1A F4 
1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 
1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90 1A 90
330i
Code:
19 78 19 78 19 78 19 78 19 78 19 78 19 78 19 78 19 78 
19 78 19 DC 19 DC 19 DC 19 DC 19 DC 19 DC 19 DC 19 DC 
19 78 19 78 19 78 19 78 19 78 19 78 19 78 19 78 19 78 
19 78 19 DC 19 DC 19 DC 19 DC 19 DC 19 DC 19 DC 19 DC 
19 78 19 78 19 78 19 78 19 78 19 78 19 78 19 78 19 78 
19 78 19 78 19 78 19 78 19 78 19 78 19 78 19 78 19 78
1A90 = 6800
1978 = 6520

Seems to correspond to the RPMs. What I don't quite get are the values in the middle that don't quite match (bolded). 1AF4 and 19DC both correspond to the rev limits + 0x64. And then the ZHP has a couple values in the middle that are way low (1504 = 5380). Not really sure what to make of that. But I do believe that block of numbers has to do something with the rev limiter - the rest of the differences in the tune seem to be either checksums or maps. By and large the tunes are very similar. That block of RPMs is the largest block of differences.
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Last edited by TerraPhantm; 09-26-2013 at 09:17 PM.
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