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Author Topic: Constant/MAP name for VSS conversion to speed?  (Read 5938 times)
julex
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« on: May 04, 2011, 08:11:01 AM »

I have and interesting problem. As some might be aware, I am running S4 M-box file on my allroad and I encountered an interesting issue with the file.

When ECU logging (or accessing VAG-COM blocks), the vehicle speed is off since it is calculated for a different rolling diameter tire than what my car really drives on.

I assume that ECU is calculating current vehicle speed off some signal from ABS module. The signal interval is transformed into actual vehicle speed by using some formula with a constant for tire size.

My question is: Anybody knows what the constant is called and maybe even knows what offset is it at in M-Box file?

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julex
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« Reply #1 on: May 04, 2011, 04:30:53 PM »

EDIT:

Finally found it...

AIMVM
Number of speed pulses per m for signal normalization v
0x12A56
2 bytes

Finally my Allroad with S4 file shows correct speed in Vag-com/EcuX. It was off by 8% as much as Allroad's tires are larger from S4 (my size anyway)
« Last Edit: May 05, 2011, 03:41:27 PM by julex » Logged
nyet
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« Reply #2 on: May 12, 2011, 10:07:25 AM »


AIMVM
Number of speed pulses per m for signal normalization v
0x12A56
2 bytes

thanks! added to new map pack here

http://www.nefariousmotorsports.com/forum/index.php/topic,200.msg4966.html#msg4966
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