Diesel Tuning – Remap vs Tuning Box, Which is Best?

Remap vs tuning box – How they work

Generally speaking a remap and a tuning box will do the same thing, they will both inject more fuel into the engine to make more power, where they differ is in the method.

A remap involves rewriting some of the software in the engine’s ECU. A basic remap will increase the fuel pressure at certain points to make more power.

A diesel tuning box will also increase the fuel pressure and certain points but instead of rewriting the software in the engine’s ECU, it will under-report the signal coming from the fuel pressure sensor which will cause the engine ECU to increase fuel pressure until it gets the signal it expects/wants.

Different types of tuning boxes

There are two types of diesel tuning box

The vast majority deal with changing the fuel pressure but there are a minority which will alter the injector duration.

Which is best?

In my opinion, fuel pressure tuning is the way to go. Yes you will be running the fuel system at higher pressures than normal for some of the time but at no point will the fuel pressure be too high as to be unsafe.

Injection timing on modern diesel engines is extremely precise both with regards to the amount of fuel being injected and also with regards to when the fuel is injected. If the duration of fuel injection is changed, then things are potentially not working at their optimum.

There is also the argument to say if you are injecting more fuel with the same duration things will also not be optimum but in my opinion, injection times and timing are more critical than the amount of fuel being injected.

Remap vs tuning box – Which lies?

Fundamentally a basic remap and a tuning box both lie to the ECU.

The remap lies by saying X fuel pressure = Y amount of fuel when the amount of fuel actually equals Z

The tuning box lies by saying the fuel pressure is X, when it is actually Y

Is there a difference? Not really