Improving your car’s performance is no longer a question of oily mechanics going under the bonnet to tune the carburettor, distributor and points.
In cars today, the Engine Control Unit (ECU) manages the engine. The ECU is a small computer, which runs the engine and controls ignition timing, air/fuel mixture and imposes limits on speed and revs.
These variables are displayed as ‘maps’ – the VW Golf for example has 20 maps for fuel alone – and can usually be modified via On Board Diagnostics (OBD) programming without needing to remove the ECU from a vehicle. This process is known as remapping.
Remapping can increase power and torque by up to 30% and also improve acceleration as well as bringing savings on fuel consumption. Some remappers claim they can get a further six miles to the gallon on a car’s fuel saving. Unsurprisingly, there was a marked increase in interest in remapping when petrol prices were reaching record highs.
Remapping can mean safer overtaking with power when it is needed, improved torque for towing capability and enhanced throttle response, ironing out torque curve dips and bringing a smoother power curve with less gear changes.
Mapping expert John McGovern of North East Remaps, Cornsay Colliery, County Durham, explains: “There are many benefits to getting an engine remapping done on a car, including higher performance at a more affordable rate than buying a brand new car.
“ECU remapping is an option that is growing in popularity for many car owners. They have a car they love, but they wish that it went faster or was more economical.’’
Why then, you might ask, don’t manufacturers do all this as standard in the original map? Well, some do offer a performance upgrade package.
But generally, when the manufacturers build their cars, they have to set up the ECU to deal with varying fuel qualities and different operating environments across the world. They also have to meet the various requirements on vehicle emissions. However, when you get your car remapped in the UK, the technicians who remap it can optimise the ECU’s programming for the UK environment to give the best power or efficiency or even both.
Remapping can also modify a car’s performance to suit a particular driver’s style and requirements, providing a greater flat out speed or giving more power for initial acceleration.
Remapping can take from 1 ½ hours to a day and it is not always high performance cars that take the longest.
So, what’s the downside?
Some manufacturers say they don’t recommend any power enhancements because the vehicle warranty could be compromised or revoked on any parts failure related to those enhancements.
On the other hand, remapping companies say they work on many vehicles under manufacturers’ warranties with few disputes and they will often offer a back-up warranty to make up for any problems over the manufacturer’s cover.
Furthermore, professional remappers will tell you that remapping is often not detected by service centre technicians, making warranty problems less likely.
Manufacturers also claim remapping will shorten the life of a car by removing performance limitations.
However, remappers argue that when manufacturers develop an engine, they design it with the capacity for more performance and remappers simply access this without threatening the car’s longevity.
“A car is never tuned beyond what an engine can take,’’ says John McGovern.
He does, however, point out one possible disadvantage in remapping. An owner must tell their insurer about any change to a car and premiums will probably rise as a result. However, remapping shops will usually advise customers on which insurance companies will look more favourably on their modifications.