A guide to car engine remapping

Remapping a car is an increasingly popular way to boost your car engine’s power and performance. But what is it, how much does it cost and will it affect your car insurance?

Read our guide to car engine remapping and decide whether or not it’s worth it.

Remapping a car is an increasingly popular way to boost your car engine’s power and performance. But what is it, how much does it cost and will it affect your car insurance?

Read our guide to car engine remapping and decide whether or not it’s worth it.

Written by

Rory Reid

Car and technology expert

Last Updated

9 FEBRUARY 2023

4 min read

What is car engine remapping?

Remapping a car – also known as ‘chipping’ – means adjusting the programming on a car’s Engine Control Unit (ECU) microchip to overwrite its factory settings. This allows your car to function at its full potential.

How does remapping a car work?

The ECU is a mini computer that controls a car’s engine function. On cars made before 2000, the ECU chip could be manually removed, retuned, soldered and replaced. In more modern cars, the new tune can be done by connecting a laptop to the car’s onboard diagnostics port via a cable.

When a car is manufactured, the ECU software settings are typically programmed to limit its performance capabilities in all kinds of driving conditions and regions. This means the car is programmed to comply with regulations, including noise and emissions, and to have a longer life (as it will be adapted to particular climates, terrain and fuel standards). Limiting the ECU capabilities also means the manufacturer can release a faster, more powerful model at a later date without having to redesign the engine.

Remapping the software and fine-tuning the engine can increase a car’s power and torque output, maximising its overall performance by as much as 35 per cent. All kinds of parameters, such as ignition timing, air/fuel ratio and turbocharging boost pressure, can be tweaked to change performance.

We strongly recommend that you only let a qualified specialist remap your car, otherwise you risk damaging the engine. The procedure only takes about half an hour and, if done properly, you should notice an improvement in performance almost immediately.

What are the benefits of car engine remapping?

The main reason drivers get their engine remapped is to boost a car’s speed and power. But car engine remapping can bring other benefits:

Better fuel economy. If you go easy on the accelerator, remapping could help to increase your car’s mile per gallon (mpg) and overall fuel economy by optimising how much fuel is burned. You could save money and reduce your carbon footprint.
Better control and driveability. With an enhanced throttle and faster engine response as you press the accelerator (high torque), your car may feel smoother and easier to drive. You’ll have greater confidence when overtaking too.
Easier towing. If you use your vehicle to tow a heavy trailer or caravan, remapping will give it extra power, so it won’t have to work so hard when climbing or accelerating.

What are the disadvantages of remapping a car?

If remapping is done incorrectly or on particular types of vehicles, drivers may experience some disadvantages:

Only turbo-powered engines will fully benefit from a simple engine remapping. If your car is a non-turbo petrol model, it’s unlikely you’ll notice much difference in brake horsepower (bhp) from a remap alone.
Greater power can also mean more strain on the engine. Be prepared to have your car serviced more frequently as major components, such as the clutch, may suffer greater wear and tear.
Once your car’s been remapped you may need to buy higher octane fuel, which is usually more expensive
If you get a remap that isn’t approved by the manufacturer or approved dealership, it may invalidate your car warranty.
Remapping your vehicle could have an impact on your car insurance. In fact, some insurance providers won’t cover remapped vehicles at all.

How much does a remap cost?

The cost of remapping your car will likely depend on the make and model, and the level of remapping you want done. But you can expect to pay £200 to £400, most of which will be labour costs. If you want your car tested on a rolling road to check the results of any remapping, you’ll typically need to pay extra.

If you opt for higher stages of remapping and reconfiguring your engine, such as new air filters or a new exhaust, it could cost closer to £1,000. And the most comprehensive type of remapping, including a new turbo system or extensive engine works, could mean shelling out thousands.

Do I need to tell my insurance provider if my car engine is remapped?

Yes, you need to tell your insurance provider if your car engine has been remapped. In car insurance terms, remapping or chipping is considered a car modification, even if it’s one you can’t actually see. If you don’t inform your insurance provider, it could invalidate your policy.

Car engine remapping could mean an increase in the cost of your car insurance premium. And even though remapping is increasingly common, there are some insurance providers who won’t cover your car if it’s been chipped.

Where can I compare car insurance for remapped cars?

Start a quote with us and we’ll provide you with a list of insurance providers that may offer insurance for a remapped car.

If your car has been remapped, remember to notify the insurance provider before you buy a policy as it’s possible you’ll need specialist modified vehicle insurance.

Frequently asked questions

Where can I get my car engine remapped?

Plenty of local garages offer remapping as a service – some will even come to your home. But it’s important to do your research and go with an authorised company. Some less-reputable companies may get rid of your car’s emission-limiting software altogether, which is illegal and means your car will fail its MOT.

Will my car fail its MOT if it’s been remapped?

There are stories of remapped cars flunking their MOT because they failed the emissions test. But as long as your remap is carried out by a reputable firm, this shouldn’t be an issue.

Is remapping bad for your engine?

As long as you use a reputable company, your engine shouldn’t experience any damage. But if your engine is tuned for more power, this will put more strain on other components –including the brakes – if you drive faster as a result. You might need to get your brakes replaced more often.

Can you get any car remapped?

No, not all cars can be remapped. Older models – typically those manufactured before 2000 – may need their chips physically modified (which involves removal and soldering or replacing), rather than a simple software update or remap. Some manufacturers also locked chips to prevent remapping, but many tuning companies have found ways around this.

The cars most commonly remapped tend to be those with turbo diesel engines – they might have TDi, HDi or CDTi in the model name. These are the models that will see the biggest improvement for relatively little cost. You can call a specialist and ask what the benefits are for your particular make and model of car. Some specialist remappers will give you a quote online, based on the make and model of your vehicle.

Will my car be less fuel efficient if I get it remapped?

If you use it properly, your car may end up being more fuel efficient. But it also depends on your driving style. If you make the most of that new-found power and push your foot on the accelerator, you might find yourself making extra trips to the petrol station.

But the good news is that if you’re the owner of a turbo diesel car, then you’re likely to make fuel economy gains with remapping. This is because it adds torque at lower rev ranges, meaning the engine doesn’t have to work as hard.

What is the difference between engine remapping and chipping?

They’re the same thing; both refer to the process of modifying the car’s onboard computer. But, typically, remapping is done via the car’s onboard diagnostic port. With chipping, the chip may need to physically removed and updated or replaced.

If I sell my remapped car do I have to tell the buyer?

If your vehicle has been remapped, then it’s a modification so you should tell the buyer or any dealer that you’re trading your car in with. It’s a good idea to keep the paperwork to show what’s been done.