944 Turbo DIY TunerPro Chips

Talk and Tech about turbocharged 924/944/968 cars
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pizatski
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Just dropping in to say a huge thank you for all of the tuning information, guide, chip info, XDFs, and BINs - I was able to decode what this Max DME III chip was actually doing and I was able to successfully program a PicoRom EEPROM emulator with a custom tune to start dialing in my modified 944 Turbo! This is turning into a really fun, and meaningful, project for this web engineer.

Next steps are getting an analog-to-digital DAQ so that I can start gathering data and telemetry from the car and wideband while tuning it.

For background, I got started down this bit of a rabbit hole because I blew the head gasket on track at Road America last year and thought it might have something to do with the combination of unknown chip, aftermarket mods, and lower octane gas the 2nd day causing knock. After looking at the timing advance and fueling maps in this aftermarket chip, I was getting away with it. Now, I'll be able to really dial in the setup for reliability and power.
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- Patrick S.

1986 944 Turbo
2011 VW Touareg TDI
PCA Chicago Region

#71

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Tom
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pizatski wrote: Fri Mar 06, 2026 1:15 pm Just dropping in to say a huge thank you for all of the tuning information, guide, chip info, XDFs, and BINs - I was able to decode what this Max DME III chip was actually doing and I was able to successfully program a PicoRom EEPROM emulator with a custom tune to start dialing in my modified 944 Turbo! This is turning into a really fun, and meaningful, project for this web engineer.

Next steps are getting an analog-to-digital DAQ so that I can start gathering data and telemetry from the car and wideband while tuning it.

For background, I got started down this bit of a rabbit hole because I blew the head gasket on track at Road America last year and thought it might have something to do with the combination of unknown chip, aftermarket mods, and lower octane gas the 2nd day causing knock. After looking at the timing advance and fueling maps in this aftermarket chip, I was getting away with it. Now, I'll be able to really dial in the setup for reliability and power.

PXL_20260303_141629231.jpg

PXL_20260306_205711429 (1).jpg
Awesome -- once you have access to the maps like that, you'll never go back to off-the-shelf chips! Does that emulator work with TunerPro RT to allow for real-time map edits?

#72

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pizatski
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Awesome -- once you have access to the maps like that, you'll never go back to off-the-shelf chips! Does that emulator work with TunerPro RT to allow for real-time map edits?
Thanks, Tom. I agree completely - I won't be going back.

The emulator doesn't work natively with TunerPro RT, but it does have a fairly simple command line interface. The workflow looks something like this:

1) Install pre-requisites (TunerPro or TunerPro RT) and the picorom CLI
2) Open the appropriate BIN in TunerPro with the appropriate XDF (in my case, the 28 pin configuration)
3) Make changes, save them
4) Use the picorom CLI in the command line tool of your choice (Powershell for me) to upload the BIN you just modified to the picorom in 64kbit mode which is what the DME expects
5) Test on road or dyno, continue modifying tune as needed
6) Commit it to the onboard flash if you want it to persist after the picorom is powered off

Steps 2 - 5 can be done with the car running and the laptop connected to the picorom while installed in the DME. When updated, changes take effect immediately in the car so you can tune on the fly. When committing to flash, the chip is power-cycled and the car shuts down so that's more of a last step after tuning session type thing to live with what you just did until you burn an EEPROM.

I haven't dug into it much, but I'd imagine it wouldn't be too difficult to make a plugin or script with TunerPro which would upload to the picorom upon save immediately.
- Patrick S.

1986 944 Turbo
2011 VW Touareg TDI
PCA Chicago Region

#73

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