NefMoto

Hey,
I've seen a lot of tuners say its possible on similar car like mine.

Audi S6 C5 4B 2004 4.2 ANK
Serial Numbers:
0261207632 BOSCH
4D0907559AB AUDI
Me 7.1.1

But I don't understand how it should work to switch pops bangs through A/C. I got pops and bangs through altering some tables: KFNWEGM, KFZWMN and KFZWOP. But I need to flash the ECU everytime to disable/enable it.

I've found DNWEK map which only contains the RPM value 1x1 and tried setting it to 8000 but it didnt work. I'm also searching the maps myself in my Dump maybe I didn't find the right one because its only one value and so its very hard to find for me as a beginner.

Maybe someone can explain it to me or show some other way? Thanks a lot!

What is the a/c? Air condition?

DNWEK normally adds 160 RPM to the overrun fuel-cut threshold whenever the AC compressor is active. By setting it so that the total fuel-cut threshold is above your rev-limiter you are basically disabling overrun fuel-cut for the whole RPM range as long as the AC compressor is running. You still need to retard the timing in the areas required, otherwise you will still burn all the fuel in the cylinder.

Interesting, i'm willing to try this little "hack" out, though i don't quite understand the logic behind this. What is the connection between AC and overrun? Sorry if i misunderstood.

It's all in the Funktionsrahmen, read it. ;) E.g. when you completely let off the throttle in 3rd gear at 3000 RPM the ECU cuts fuel until the RPMs dip below the cut-off threshold in KFNWEGM, 1120 RPM for a fully warmed up engine in 3rd gear. It then starts injecting fuel again, otherwise you would just continue engine braking until you come to a complete stop. DNWEK just adds 160 to 1120 RPM, making the threshold 1280 RPM when the AC compressor is running. The compressor robs the engine of some torque, I guess that's why they increase the threshold slightly when it's running.

Thanks for the clarification, i understand now. I looked at the "Funktionrahmen" but didn't quite understand yet. So i could set DNWEK to something like 6000 (max RPM= 6800), overrun will always be disabled when AC is running.

Thanks again! As i could not find much regarding DNWEK online. If i can find the value tonight in my BIN i'll give it a go!

Just don't destroy your exhaust/cat  ;D

Just hook it off Cruise Switch. Its way easier...

Thanks for the heads up haha, running catless downpipe and a milltek exhaust so should be good!

Is it really though, you are referring to map switching i suppose?

Yes it really is. You just set a JNB for the Cruise control Main switch on your ASM code and off you go.

If your just using the rev limiter for cut then this will not work. But my code runs stationary Limiter at 5400 (soft limit). and Hard cut (pops and bangs) at 4800. one line of code. Jump out of logic if Cruise is set. Done.

Perhaps i've still misunderstood; i went ahead and found DNWEK in my bin, I changed from 160RPM to 6000RPM. But instead of AC switch disabling overrun it instead  disables fuel cut entirely thus popping/banging untill timing is back to standard.

Do you mean the AC switch has no effect on the outcome? That's strange. DNWEK is conditional, it depends on the B_koe (compressor on) flag being set, else it won't be considered.

Or, do you mean it crackles all the time when letting off? This approach does just that, basically crackles and bangs all the time while coasting in gear. I've looked at the schematics on how to put a time limit on it, I'll check in again tomorrow.

It crackles all the time when letting off, thus disregarding KFTVSA value of 2.5 sec. What i'd like is that AC-on disables overrun and thus also pops&bangs.

Thanks for helping out. May i ask where do you find these schematics? I'd be very interested to have a look myself too!

Overrun & fuel-cut is on page 710 in Funktionsrahmen (Betriebsbereich Schubabschalten/Wiedereinsetzen).

Cool, thanks. I'll have look tomorrow, would be really nice if i could get the AC-on state to disable overrun.

Ok thanks guys, now i kinda got it. Of course setting it for the cruise control would be the better way and I've hacked programs (actually games) with ASM on my computer some time ago already (beginner steps tho).

But I dont understand exactly in which code you have to make these changes for the cruise control? in the ECU .bin dump!? That doesn't really make sense bc it only contains maps or not?

And where do you jump to after? To own code in code cave which u have to program?
And how can you test your code without killing the ECU by flashing maybe bad code?^^ because I'm noob and only understand it kinda theoretically.

I'd like to look on the code of cruise control myself in ASM but I dont really know where to search lol.
My second problem is for my car there's no DAMOS on the web so I have to search everything myself!

Thanks a lot tho will try to figure it out with A/C first! But yea I'll need the other map changes too so the only real way would be cruise control I guess for it to pop.

some example to look at (in a youtube video or something) would make it a LOT easier if there's something out in the internet.

I'm ofc not a chip tuner and just want to get it done on my car also I'd like to fit in a WOT BOX in combination so it would be nice if I can simulate clutch presses while shifting (automatic) that's why I'm trying to play a bit with the code :D Maybe it's not too hard to get it done!

Edit: Another thing not quite clear to me: if I make changes to KFZWMN and KFZWOP, do they affect normal driving also and could cause possible damage in long term or are there maps that are ONLY active for overrun? Because in KFZWMN the min limits for iginiting are set, so could anything go wrong possibly if i modify it while driving "normal"? I guess best for the engine would be to only use modified maps when cruise control is pressed so i guess I'll have to mess with it till i get that done guess that would be best for long term !?

this is all answered here but you seem pretty earnest, so I will reply a little beyond just "use search." andy whittaker's videos give you a good idea of how to take apart the bin file into disassembly so you can figure out how things work https://www.youtube.com/watch?v=UJAVIOrD8fw . if you search here prj has a lot of good scripts for labeling ram and rom (calibration) variables from damos/a2l. also if you use me7info you can find ram locations, which you can then label in the disassembly. it takes a long time to learn this stuff. yes, the basics of making a patch are to branch from a routine you know about into an unused area with your own code and then jump back at the end. finding unused flash is easy (empty parts of the bin), making sure that any temp variables you use in RAM are not over-writing something else is a little harder. the ECU runs a real time OS where different tasks run on different periods (i.e. some tasks run every ms, some every 100ms, some every crank revolution, etc.), eventually you learn good places to inject your code. http://nefariousmotorsports.com/forum/index.php?topic=641.0 should help you too. good luck!


no, the .bin is the full operating software for the ECU.


bootmode keeps you from bricking your ecu even if you completely mess up the application software.

Do you think there is an option to make this work sort of in reverse? All i could come up with is putting a negative value, but i don't think that can fit in 1 byte.