ECU Remapping

Remapping – What is it? A simple guide

Getting the most from your car in terms of performance and economy is a great way to improve your overall driving experience and save money on your fuel costs over the months and years. While tuning a car for optimal performance may sound daunting and complicated to many casual motorists, you may be interested to hear that it can be done in as little as 30 minutes, by ‘remapping’. In this guide, we’ll explain what the term ‘remapping’ means, and what happens when you remap a car.

Remapping, sometimes called ECU tuning or chip tuning, is when the settings of a car’s ‘engine control unit’ (ECU) is altered to improve several areas of the vehicle’s performance. By overwriting the existing settings with new software, the owner can reprogram the car to manage the fuel injection, airflow, sensors and more (within legal limitations) It’s the same principle as your home computer.

How does remapping work?

Remapping a car changes the manufacturer’s default settings within the ECU, replacing ‘values’ with the new settings which can be tweaked and customised to the owner’s specifications (within legal limitations).

When a vehicle is remapped, the old ECU settings are overwritten when the customised settings are written, the remap ‘agent’ will now have a ‘saved’ copy of the original ECU settings, which can be restored at any time and thus bring the vehicle back to how it was originally! This is done while (usually) plugged in to the vehicles serial port (sometimes referred to as an OBD port). This simple functionality has made the process of tuning a vehicle considerably easier, and has created many jobs for tuning engineers and specialist ECU software developers.


What does ECU remapping do?

As mentioned above, remapping allows you to alter the performance of your vehicle by altering how the engine drives the car, however, it’s how the driver chooses to use the tuned car that ultimately decides what effects the ECU tuning will have.
For example, it’s a common belief that remapping a vehicle has no effect on fuel economy, however, this technically isn’t true. As the result of ECU remapping, a car usually sees an increase in power and torque, which can come at the expense of higher fuel consumption but often doesn’t. Owners will often drive their cars more ‘enthusiastically’ after remapping, accelerating quicker when possible to enjoy the noticeable difference in output their car has, and therefore, further increasing fuel usage.
On the other hand, if the driver chooses to change their driving habits to make the most of the increased power and torque throughout the ‘rev range’ and gear changes, then fuel economy can be improved. It really comes down to how the driver chooses to use the tuned car which decides how economical it becomes.

Remapping a vehicle can also have an immediate effect on speed and power; in some cases, remap agents claim to have increased horsepower by 30-40bhp, and torque up to 80nm! These figures are usually set by manufacturers and your remap agent will be able to advise how ‘much’ of a difference you should see.
A car’s engine can also become more responsive, allowing the driver to overtake more easily. This can also cut down on the number of gear changes the driver has to make, allowing them to handle situations that require more torque without dropping down to lower gears. Again, this can help boost fuel economy if used strategically.

Should I remap my car?

Many people might wonder ‘Is remapping a car good or bad?” As with all car modifications and maintenance, remapping a vehicle does come with risks and downsides, so it’s worth bearing these in mind before you decide to go ahead with the process.
Firstly, it’s important to remember that not all cars can be remapped, usually due to their age. Typically, cars produced before 2000 are too old and don’t feature the car remapping settings needed to optimise the vehicle’s performance.
If you aren’t an expert in the industry it is not advisable to remap your own car. Choosing a reputable company to carry out the remapping is a good way to reduce the risk of anything going wrong. More established businesses that provide a remapping service will offer a lifetime warranty on the replacement software, giving you a safety net should you notice any issues in the future. Generally though, once a vehicle is remapped and tested on the day then nothing will alter that.
Remapping can also affect your insurance premiums. It’s very important that you inform your insurance company of this (or any other) modification, so you do not risk leaving your policy invalid should you need to make a claim. Some insurers refuse to insure a vehicle that has been remapped, so it may well be worth checking with them beforehand to see how the process would affect your premiums, and if the increased prices are worth the increased performance! However, the legal argument here is that your newly purchased vehicle could already have been remapped without your knowledge! There is no real way an insurance company can prove this either way! However, dealers can! So taking your car back to the dealers (should it still be in warranty) will make this void!
If you are looking for a way to get the most from your current vehicle, a performance remap may well be the answer. The process has many benefits as well as downsides, and a reputable remapping company will be more than happy to explain those to you before you decide to go ahead.


As an example : VW produce a 2.0tdi engine which is basically fitted to most of there range of car’s and van’s, these engines can range from 80hp to 170hp, generally when reading information from the ECU the remap agent will be able to see how the manufacturer has ‘capped’ this hidden power from the same power plant and thus be able to turn your 80hp into more than double without loss of reliability or fuel economy!