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Author Topic: KFZW/2 16 bit axis patch  (Read 5041 times)
fragolas
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« on: May 23, 2023, 11:30:17 AM »

As you may know, the me7.1 and me7.3 uses rl and nmot ( 8 bit) instead of rl_w and nmot_w(16 bit) for KFZW/2 axis, this in turn caps the max load at 191.25, the me7.5 solves this problem.

To solve this, a patch needs to be aplied in the ecu code, keep in mind i dont have this issue, my max load is below this limit, so i havent tested this.

First, you need to find ZWGRU function in your ecu using IDA and see wich axis it uses, 8 bit (snm16zuub and srl12zuub) or 16 bit(snm16zuuw and srl12zuuw).

My ecu uses 8 bit, as seen in the screenshot.



me7.5 uses 16bit, as seen in the screenshot.



The function call, as the rest of the code is the same  so no need to modify that, just patch the code so that it uses the 16 bit axis.

It should look something like this



my axis in ram are like this



After that is done, you need to modify your map pack(or whatever you wanna call it).

For 8 bit axis , KFZW looks something like this.



For 16 bit axis, it should look like this.



Again, keep in mind this is just theory, i havent tested this, nor do i need this, its just for educational purposes.

Happy tunning.

EDIT: if someone know how to make the screenshots appear in the text, let me know
« Last Edit: May 23, 2023, 11:32:03 AM by fragolas » Logged
nyet
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WWW
« Reply #1 on: May 23, 2023, 02:16:11 PM »

Binary for b5s4 551M for reference
https://files.s4wiki.com/patched/8D0907551M-0002%20(16Bit%20KFZW)-2019-06-23.zip
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fragolas
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« Reply #2 on: May 23, 2023, 04:11:47 PM »

I forgot to add, you must also change "r13", as srl12zuub or srl12zuuw is loaded into r13. to do that, check wich adress srl12zuuw is loaded from, and patch the r13 instruction. Screenshots for reference.
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R32Dude
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« Reply #3 on: May 23, 2023, 04:22:06 PM »

Nice!
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pOwy
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« Reply #4 on: July 28, 2023, 12:57:39 PM »

Hi!

Some of the Fiat Me7.9.10 is also limited to this, i will look into this, but anyway thanks for the info.
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le mans
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« Reply #5 on: December 15, 2023, 11:49:41 AM »

The B5 RS4 with ME7.1 uses a 16bit axis for load. There is an xdf and bin for the 551F ECU (ASJ engine code) on the S4wiki site if you want to go take a look.
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