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Tuning Box

Tuning box functionality

Tuning Box, Power Box or Dieselbox

there are many names on this solution. What these have in common is that the principal function involves distorting the signal from a small number of sensors in order to increase power output.

In a Common-rail engine (today's diesel technology) it's the fuel pressure sensor exposed, resulting in a high fuel pressure and thus a slightly increased fuel flow. Older engines with electronically controlled distributor pump, the signal from the pump feedback sensor is modified to increases flow.

We have tested some different solutions for the Mitsubishi L200 (136hp common rail engine) engine in our laboratory. Some of the results are presented below.
System 1

The system comes with an installation manual describing the physical installation and the option to alternate between ten different "modes" (0-9) by turning a knob. "0" according to the manual is the same as standard mode, "7" or "8" is default and should only be changed if the engine is goes into limp mode at the trial run. According to the manual, the change in signal from the rail pressure sensor provides longer injector duration as a result. This is not true; it only gives a pressure increase.

Electrical characteristics

The system's output voltage as a function of input voltage was measured. It turns out that the "0" to "5" is the same and the "0" is not at all standard, as the manual says.

Rail pressure - fuel pressure

The modified signal results in an increase of the maximum fuel pressure from 1730 Bar to 1900 Bar. It should be noted that the manufacturer of the fuel pump has set an upper limit of 1800 Bar.



This system promises a power increase of 18%. The real increase is 6% in position "8" as it is delivered. In  position "9" (which in certain driving conditions provides reduced output and error codes) the power increase is only 10%.


When testing position "8" and "9" the design limit of the turbo charger in terms of maximum temperature was exceeded. Exhaust temperature close to 900 ° C was measured.


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Visiting address: Njurundavägen 16, 862 40 Njurunda, Sweden. STT Emtec, engine and emission technology.