Your Introduction to Remapping A Car

Considering remapping a car? In this article, we’ll explain exactly how it all works, so you can decide whether it’s the best option for your vehicle.

Engine remapping is one of the most popular methods of car modification. And that’s no wonder. Remapping a vehicle is relatively easy to do, and, compared to other vehicle modifications out there, it’s often fairly affordable, too. 

But there are some serious implications to having your car remapped, so you want to make sure you’ve done your research (reading this article is a good start!) before taking the plunge.

Let’s begin with the basics.

What happens when you remap a car?

So, what does remapping a car mean? 

When you remap a car, you alter the piece of software that controls how the electronic control unit (ECU) performs. The ECU, which is also called the engine control unit or engine management system, is responsible for the vehicle’s electronic fuel injection system.

Remapping (or “chipping” as it’s sometimes known) overrides a vehicle’s factory settings with the aim of “tuning” the ECU, and improving its power output. 

These factory settings, found on so-called stock vehicles that come from the manufacturer, aren’t just randomly chosen — they’re there for good reason. Although the chosen factory settings for the ECU can limit a vehicle’s performance, their benefits include improved reliability and fuel efficiency, and compliance with important regulations on safety and emissions. 

Certain models, including those designed for specific terrains, may have ECU settings that have been intentionally chosen to optimise the overall life of the vehicle — but compromise on vehicle power.

How is car remapping done?

Despite its importance for the running of a vehicle, the ECU is actually just a set of small computer chips that (these days) are fairly straightforward to reprogramme. 

Rather than having to replace the ECU entirely (as used to be the case pre-2000), today, a trained mechanic or technician can physically connect a laptop to the ECU through the onboard diagnostic (ODB) port and change its performance settings in a matter of minutes.

As well as serving as an access point for remapping, the ODB port provides mechanics with a universal connector that they can use to troubleshoot and diagnose more general issues with a car’s engine. 

However, since the remapping process substantially alters the way a vehicle’s engine performs, it should always be carried out by a trained professional. It’s important the car still performs as it should from a reliability and safety perspective. 

Which cars can be remapped?

Not all car makes and models benefit equally from engine remapping. And for older cars, (made before the millennium), remapping is a much more involved process. Some cars are just too old, and can’t be remapped at all. 

Your vehicle’s fuel type and whether your engine is turbocharged are crucial factors, too. For example, the performance of turbo diesel engines tends to benefit the most from remapping, whereas the benefits of remapping a non-turbo, petrol-fueled vehicle tend to be much less substantial. 

Is remapping illegal in the UK?

No, remapping a car is usually legal in the UK — as long as the changes that are made stay within legal limits in terms of certain criteria, like emissions.

To stay on the right side of the law, it’s also crucial that you tell your insurance company about the changes to the vehicle to maintain the validity of your policy. A remapped car is considered a “specialist car”, and therefore needs an insurance policy specifically designed for specialist motors. 

What are the advantages of remapping a car?

Increased power (and the associated gain in speed) tends to be the main reason an owner chooses to remap their car. 

But there are other potential benefits, including: 

Improved fuel economy. As long as you’re not always revving the accelerator, you can improve a vehicle’s fuel economy by engine remapping because it has the potential to increase the vehicle’s mileage per gallon. 

Better drivability. Increased power and engine response can improve overall driveability, with the potential for ignition timing and control. 

Engine remapping has other practical upsides, too. The process can be reversed for most modern cars, simply by reinstalling the factory settings onto the microchip. 

And, because there are no physical upgrades in engine remapping (like new tyres or a new engine) it’s a relatively cheap way to improve your car’s performance. 

What are the disadvantages of remapping a car?

But, as with many things in life, the potential benefits gained by remapping can come with some downsides. These include: 

Increased insurance premiums. Once your car has been remapped, it’s counted as a specialist vehicle and this requires specialist motor insurance, which can have higher premiums than standard car insurance policies. And since you’ll need to inform your insurer as soon as your car’s been remapped, you may have policy change fees to cover as well. 

Voided warranty. If you decide to remap your engine, make sure you understand where (and even if) you can have it done without invalidating the warranty. If remapping is possible according to the terms of your warranty, ensure that it’s done by the manufacturer or an approved dealership as specified in your car’s paperwork.

A less reliable vehicle. The increased power that engine remapping brings can put extra stress on your engine, brakes, clutch, suspension, and tyres. As well as meaning more money on repairs in the long run, you might find that your car is less reliable after remapping. 

Decreased fuel economy. We mentioned earlier that engine remapping can actually lead to better fuel economy — and that’s true if you can increase mileage per gallon. But, it all depends on your driving habits. If you keep slamming on the accelerator to make the most of your car’s increased power, you might actually find that your car becomes less fuel efficient, not more. 

More expensive fuel. Engine remaps can increase the octane rating of the fuel needed for your car, and that often comes at an increased cost.

Safety considerations. The factory settings of your car’s engine have been specifically chosen and tested in a range of conditions. When you remap your car’s engine, the safety of the car under these different conditions, for example in extreme conditions, can’t be guaranteed. 

How much is a remap in the UK?

Car remapping tends to come in three stages, each associated with a different price tag and performance improvement potential. 

Stage 1 remap

This level of car engine ramp tends to cost in the region of a few hundred pounds and involves slightly tweaking the settings of the ECU to deliver a small performance boost. 

Stage 2 remap

For this stage, the exhaust and/or the inlet are modified alongside the ECU changes made for stage 1. The exact changes tend to depend on your car’s fuel type and typically come in between £500 and £1,000. 

Stage 3 remap

The most dramatic changes happen during a stage 3 remap. These can include the addition of things like rods, pistons, fuel pumps, and turbochargers to the engine. Such significant changes can seriously increase your car’s power, throttle response, and torque but this level of remap tends to be quite pricey — you can expect to pay over £1,000.

In summary: remapping your car

Remapping your vehicle can lead to notable increases in performance. But it’s not a decision to take lightly. 

Remapping your car can fundamentally change how your car functions, with potential consequences for the fuel efficiency and safety of your vehicle. It may also invalidate your car’s warranty, meaning you’ll need to take out specialist motor insurance that can be pricier than a more standard car insurance policy. 

So before you go ahead and remap your car, we recommend you do your research. Chat to your manufacturer or a qualified mechanic, and always tell your insurer about any modifications you decide to make. This will make sure you and your vehicle stay safe on the road and on the right side of the law. 

Speak to us about our specialist motor insurance and our modified and custom vehicle insurance for more information.

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