Engine remapping and car chipping: does it work?

If you’ve not previously heard of engine remapping, you’re one of a shrinking number as the practice gets more and more popular. In recent years drivers have become more familiar with the little black boxes that control their cars vital functions, and more aware of the opportunities to ‘tweak’ the settings.

The process used to be called chipping, as it literally meant swapping a microchip in your car’s Electronic Control Unit (ECU) with a modified version. Nowadays the black art has advanced to the point where home-brewed engine remapping software is available to download from various internet groups for brave and/or tech-savvy home-tuners who like to experiment. We’d never recommend that route, as unsurprisingly there’s a significant risk of causing expensive engine damage if a remap is not done properly.

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So for most people an engine remap involves a trip to a local specialist who can overwrite your factory engine settings via a laptop, or ordering a handheld device like the Superchips Bluefin. This is a DIY unit that plugs into your car’s Onboard Diagnostic Port (OBD) and will overwrite the engine map with an upgraded version in around 20 minutes – or revert to the standard factory map just as easily.

Other remapping systems include the one produced by RaceChip which adds a small extra ECU to the wiring loom and provides remote control of a range of engine map settings as you drive, either by a hard-wired rotary controller or wirelessly via a smartphone app. It may sound radical, but in fact it’s little different in concept to the selectable drive mode settings provided as part of the spec by many car makers these days.

Why bother with a remap?

There are two primary reasons for wanting a remap, and they’re called power and torque. When your car left the factory there’s a very good chance its performance was deliberately muted in order to meet product planning objectives or economy and efficiency targets.

These days the power and performance of most cars is limited, not by any particular mechanical factor, but by the software running in the engine control unit (ECU).

Computer algorithms running behind the scenes while you’re driving a modern car affect all sorts of parameters, such as ignition timing, air/fuel ratio and turbocharging boost pressure.

So if you want greater performance and pulling power from your car, or alternatively if you’re seeking mpg improvements, the first place to look is the little black box under the bonnet. Here at Auto Express we receive plenty of emails asking advice about ECU software changes, and we’ve compiled this guide to explore the pros, cons and costs.

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. It’s these turbo diesel engines (often known as TDI, HDi, CDTi depending on the manufacturer) that are cornerstone of the car chipping industry because an engine chip or software upgrade can cheaply add so much to the performance.