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Limitations of Aftermarket Diesel Tuners

The sentiment of a famous country song says it all: There can’t be a girl too pretty or a car too fast or – in this case – a diesel engine too powerful! The promise of added performance with a diesel tuner is a siren song that’s easy to fall prey to. Before you invest in one, you need to understand how a tuner works and its possible ramifications. 

Electronic diesel
The modern diesel replaced the pump-line nozzle system with common-rail electronic injectors. Also integrated is usually turbocharger boost control. Thus, the amount of fuel, the timing of the injection pulse, and the boost pressure can all be manipulated electronically. In the parlance of engineering, the software in the electronic control unit (ECU) is known as the calibration.

The ECU is able to be recalibrated (reflashed) to alter the timing and length of the injection pulse along with the boost pressure. This is the source of the power gain. The calibration a diesel tuner employs is more aggressive than that fitted by the engine manufacturer.

So why can’t the factory do it? It chooses not to – not because it wants to short you on power. Its concern is reliability of the engine and drivetrain along with emissions output.

Power is produced by cylinder pressure from the expansion of the ignited fuel burning across the bore. The higher the power, the more heat generated and the greater the cylinder pressure. Heat and pressure – when excessive – will end up hurting the engine. The logic of all engine manufacturers is to build a power train that can take more power than the calibration produces. It is like building a truck that can carry more weight than it is rated for. This is the buffer for when the truck is overloaded.

An aggressive calibration either diminishes or removes the safety buffer. Manufacturers usually can tell if an aftermarket tuner is installed. Some tuners leave a fingerprint in the ECU and, in most cases, will void the warranty on the power train. The Diablo Sport InTune says it does not. The InTune is easy to use, is well supported, and is made in the U.S.

Choose wisely
A calibration that is identified for towing offers the best of both worlds in a truck that is not continually taxed.

A towing calibration will provide better throttle response, increased power, and higher fuel economy. It shrinks the safety zone, but it does not eliminate it. If the engine is really worked hard, then keep the stock calibration and go a little slower up the hills.

Why risk an expensive repair?

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