Watchdog: Engine remapping

Watchdog: Engine remapping
29 Aug, 2012 9:30am Jon Morgan

What are the benefits and potential drawback of getting your engine chipped? Auto Express investigates...

If you want more power or economy from your car, it’s worth considering a remap. This alters how the engine works in order to improve performance, and is also known as chipping. We get lots of letters and E-mails inquiring about this, so here we explain what’s involved.

Remaps are made possible by your car’s engine control unit (ECU). This controls the ignition timing, air/fuel mixture and (on turbo cars) boost pressure. It also imposes any speed or rev limits.

A chipping company can reprogramme the car’s ECU to change how it controls the engine and can also remove any limits placed on it. This used to be done by plugging a microchip with new software into your car’s circuit board, but these days, software can be installed using a laptop connected to its diagnostic port.

The gains can be impressive. Remapper Superchips lets you search the make, model and engine of your car online, to see what improvement it can make.

For example, its £455 upgrade for the MkVI VW Golf GTI boosts power from 207bhp to 251bhp, and torque from 280Nm to 324Nm.

Chipping turbodiesel engines can increase economy by seven to 10 per cent, because it adds torque lower down the rev range. This means the engine doesn’t have to work as hard as before.

Many companies offer plug-in kits that are pre-installed with the software upgrade. These allow owners to remap their engines themselves. It means you can restore the car’s factory settings should you wish, plus there’s no need to travel to the company’s premises.

Some people are concerned that remapping could cause problems with their car. But it shouldn’t affect reliability if you use a reputable company such as Superchips.

Its technical director Jamie Turvey told us: “Remapping does put extra strain on an engine, but not a dangerous amount. We check carefully that the temperatures and pressures our remaps put the engine through don’t exceed the acceptable parameters.”

He added that most cars’ engines are built to offer more performance than they actually deliver. “You find manufacturers launch a car with a set power figure, but then over the life of the model they’ll introduce a few facelifts and performance versions,” he explained.

“They don’t develop new engines for each new version: mostly they limit the performance of the earlier models and then offer a little more power with each new edition. We just release the optimum performance.”

Obviously, you need to inform your insurer of a remap. But you may be pleasantly surprised by its reaction, according to Turvey.

“Historically, insurers would run a mile from chipped cars,” he said. “Some still will, but for the most part it’s very different these days. Some will just say ‘thanks for letting us know’; others will have a set fee.”