Testing PiggyBack Tunes on a 2015 Fiat 500 Abarth

I have finished editing a quick video that I made when I saw an opportunity to run an HPSI Unichip Stage 2 on my car (once again!). I am currently using a Seletron ChipBox and definitely enjoy it’s additional boost, however, that HPSI tune literally wants to tear your face off any chance it gets.

The thing that I take away from the ChipBox is that it is very smooth power that is smoother than most other piggyback tunes that I’ve used (TMC, RRM). The Unichip, however, is a different breed from other piggybacks and can intercept and manipulate signal voltages more than a simple +/- so you can develop your own boost maps, AFR maps and further refine your tune. Of course, the Unichip is still ultimately limited to what the ECU will allow since the Unichip is not the top authority when it comes to operating the engine, that’s the ECU’s job. The TMC and RRM piggyback boxes connect to the Boost and MAP sensors (and a cam sensor for an undisclosed reason). Though, the ChipBox unit plugs into Boost and MAP sensors it also connects to the boost solenoid and I suspect that it is to assist in reaching its target boost levels. Thus, it removes one other trick that the ECU has up its sleeve when it wants to limit boost pressure.

Here is the video: YouTube Video


    1. I installed the piggyback modules myself. Pretty much, everything on this car is: “remove battery, then everything is accessible.”

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