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Multi-map reflash tuning

Practical Diesel Tuning

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Hello Nick,

Thanks for such an interesting diesel course!

One very interesting feature you add to your tuning jobs is multi-map tuning. It is a very useful in a multi-purpose car/truck. Could you give any insight on how this is achieved? I saw you added this feature to the Bosch EDC17 in the Roxor.

Thanks in advance.


Multi-map power tuning was introduced to the diesel performance world very early on. Adjust-ability has become a key product feature and selling point for many tuners and programmers along the way. Customers love the idea of it. I would say more often than not multi-map tuning is more exciting on paper than it is in practice. Most of my customers report that they regularly use no more than 2 of 5 available power levels. The tune they like for daily driving and the race tune for showing off. For how frequently guys change maps it's probably only marginally more difficult to flash a different file.

The Roxor platform is a little unique because the ECM cannot easily be re-flashed by the end consumer so switching power levels would require mailing the ECM back to the tuner.

The practice of setting these tunes up varies platform to platform. Sometimes (such as in the LB7/LLY/LBZ/LMM Duramax platforms) a company like EFILive will offer a custom operating complete with multiple subsets of maps for timing, boost, etc. per tune. Sometimes you can find a factory sensor that allows for torque reduction by temperature or pressure and design and discrete switch to replace the sensor to allow the customer to limit max torque based on switch position.

Hope this is helpful,


Hello Nick,

Yes, very helpful, thank you. To wrap it up, I conlude that it´s either the stock ECU´s operating system having the function ready to be activated, or the ECU having additional memory to hold modified firmware and additional maps.

Regarding the number of maps, yes, 5 positions seemed a bit excesive to me. Your comments totally confirm my hunches. Maybe 3 would be a simpler solution: 1- Valet or Stock 2-Sport-Economy 3- Race tune.

I use a variety of flashing tools and editing software depending on the aplication. My main equipment is Alientech/Dimsport but I also use others where they offer more capability. Those modified firmwares I suppose would require something like Winols or Swiftec?

I have been thinkering with the manipulation of sensor signals / maps using trimpots. My problem is the variety of cars and software versions I deal with; within the same model, control strategies change and the variable rate controller ceases to work.

Thank you once again, I really apreciate your help.


you're on the right track. For a guy operating in your position working on many different platforms using dimsport you're going to have a hard time justifying the R&D expense per platform. Typically I end up building these files in OLS after I find an .A2L or something close enough to use.

From an R&D perspective it cost me the same money and time to build five 5 tunes or 3 on the switch, hell you could probably use a rheostat and make it infinitely adjustable.


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