There comes a time with many vehicles that you feel the need to improve the performance of the engine. This may be a requirement for further performance, or just a wish to achieve better fuel economy and mileage from your car or van.
The art of diesel performance tuning is quite different from tuning a petrol car, mainly because of the requirement of the diesel fuel injection system, and the lack of an ignition system.
One of the easiest and most effective tricks is simply to change the program which determines how much fuel to inject, and when. By injecting exactly the right amount of fuel into the combustion chamber at the right time in the cycle, the engine can produce a cleaner and more efficient burn, and end up running smoother, faster, and with better economy. That assumes of course that the manufacturer did not optimise the engine as well as they may have done when the car came off the original production line.
It seems that few engines are that perfectly optimised in original form, so the owner is left with a choice of which system to use to achieve the desired result. There are two options here – either to get the original “chip” in the car (the one that contains the “map”, or the programme which works out how much fuel to inject and when). This process is known as re-chipping or sometimes re-flashing.
The other option is to buy an extra box, sometimes known as a “piggy back box”, that effects the way the main chip controls the engine, without having to actually alter the fuel map in the original chip.
Of course opinions are divided as to which is the best type of system.
Re-flashing the original chip means you do not have to add in any additional parts, or make any additional wiring connections to the engine. The prospect of re-soldering the wiring loom of a car for example would be enough to put off all but the most dedicated enthusiast. Professional race teams usually have a variety of chips or programmes available for their engines, or out of car systems which can easily re-programme or optimise the fuel map between practice sessions. However for most of us that kind of equipment is completely out of reach, and of course once an engine chip has been remapped, you cannot easily go back to the original system if you don’t like it!
A “Piggy back box” or “diesel tuning box” (widely available for most popular CDTi or TDi diesel models) provides a similar answer in a different way. The better ones are very easy to fit, and require no reprogramming or fancy electronics from the user. With proper connections they can be clipped into the loom in a few minutes, providing simple basic instructions have been provided. The smarter systems also “learn” over time, so not only do they apply a better optimised map to the car’s performance when first fitted, but they also improve that map to accommodate the idiosyncrasies of the individual engine. And of course being a plug in unit it’s also very easy to take the thing out again, if you sell the car, want to try something else, or just think it doesn’t work.
Traditionally either type of tuning system has been accompanied by concerns as to the reliability of the engine. After all, if an engine was designed to produce 100 Ps power, how would it respond to putting out 30% more power? It must be said that most production engines are highly under-tuned, making them good for significant increases without damage. However the answer seems to rest on the system you choose. It is a well designed system that gives the engine just the right amount of fuel at all times, you should experience better performance and economy with no loss in reliability. If the tuning system were to deliver the wrong amount at the wrong time, then it is possible that engine damage could occur. The better systems including the German DTE Systems brand offer engine warranties as well, allowing these kinds of concerns to be overcome.
So as with most things it comes down to quality, but with the correct selection there are significant improvements to be made, and for very little real effort or cost. A final word is that you should check your insurance policy too, as some are not in favour of after-market parts being added, so make sure first before you make an irreversible change and increase the performance of your diesel engine.
