Sometimes when driving a diesel powered RV, motorhome or tow-car we feel the need for something a little more powerful under our right foot.  Changing down too soon or having to drop too many cogs on the grades gets us thinking that it might be time to have a look at fitting a diesel tuning system.

These are widely known and every caravan and RV magazine I read has an advertisement for one or more systems.   The idea it that by logging onto the the engine electrical control unit  (ECU) and making some changes via a computer terminal you can make it work harder and go further on less fuel.  This can be done very easily and relatively cheaply with most vehicles.  It is an exercise that can lead to greater fuel economy, provided of course that you use the power for hauling your motorhome or caravan rather than reducing your 0 to 60mph record or going faster on the straight.  These of course are things that caravanners would never do, when somebody is watching at at any rate.

This photograph shows a quarter view of a diesel engine with the hood upThis exercise if often called chipping, a term more accurately applied to an older, obsolete, method of adding a circuit board or even replacing the engine control unit with another one .

With the advent of computers and their applications in the motor industry, specifically in relation to their use in engine control systems, it has been possible to standardise the performance of car types across many jurisdictions.  By producing cars that have as few variations as possible they can set up production lines that produce vehicles which will satisfy the regulations in as many countries as possible, without having to spend time making many different versions.    By connecting to the cars system in your own country it is often possible to remap it in order to tailor the performance for your area without infringing your local laws and regulations.  Do seek out a reputable firm to carry out this work as you will want to have adjustments carried out in a way which will improve the performance of your vehicle without causing damage to it or having an adverse effect on the environment.

There are other systems available also and some of these involve fitting a little electronic control unit in parallel with  your existing management system.  These are each designed and built in boxes for specific models and they are easily fitted as a DIY project.  These diesel tuning systems should come with full and comprehensive instructions so do ensure that your choice of unit includes these instructions before you buy it.  They generally plug into something that already exists rather than requiring deeper knowledge of mechanics or electronics.  Look for a unit which will allow you a reasonable time to fit it and try it out in case it doesn’t suit your vehicle.  In other words look for a full no-quibble money back offer which you can avail of within a length of time that will allow you to try using it.

Car manufacturers generally allow a measure of tolerance between what the engine actually can do and what they allow them to do when they leave the factory. This is the

A fuel tank open with a pump nozzle in place filling it with diesel

area that is exploited by fitting one of these boxes which will recognise the upper limit to which your car can perform and adjust the system accordingly.  You can therefore begin to appreciate that you really do need to be satisfied that you are buying a tried and trusted product from a reputable dealer and that you actually have the correct model for your vehicle before fitting it.

These can be cheaper than remapping, and the fact that you can easily remove the unit means that your engine will return to its earlier setting immediately.  With  a remap it may be possible to get a finer tune but it can be more difficult, and expensive to undo it, if for any reason you decide to revert to your original settings.

There has been talk of control units being sold which are less than efficient at what they do.  You need to keep in mind therefore that practically everything your car does these days is electronically controlled.  If you fit a less than perfect tuning box it can have adverse effects on other parts of the system like lighting control and fuel injection.

Usually a modest increase in power will offer you a a noticeable difference in driving conditions.  You are after all looking for the power to pull that extra little bit of load, whether it is the RV unit itself or a trailer.  You may find that an increase of even 20 or 30% in power will make life much easier.  If you use you unit a lot,  a little increase in its capacity to save on fuel will add up to good economy over the period spent driving it.  If you take you rig out for only a few hundred miles each year perhaps you might be better spending you hard earned cash on something else.

Filling with diesel by: Ines Hegedus-Garcia