What is car engine remapping?
Remapping a car – also known as ‘car chipping’ – is a way of improving the vehicle’s power, performance or fuel efficiency.
It’s done by adjusting the programming on your car’s computer to overwrite its factory settings. This allows your car to function at its full potential.
Is remapping a car legal in the UK?
Yes. There’s no law to stop you remapping your car. However, it should be done by a professional with experience in remapping, otherwise you risk damaging the engine.
How does remapping a car work?
Modern cars have an Engine Control Unit (ECU) microchip. This is essentially a mini computer that controls a car’s engine function. Remapping reprograms this computer.
When a car is manufactured, the ECU software settings are typically programmed to be suitable for the wide range of driving conditions and regions where the car is sold.
Effectively, the same settings are used everywhere, but aren’t optimised for particular driving conditions. Remapping will change these settings to make them more bespoke.
There are three stages of car remapping:
Stage 1: the software on the ECU is updated. This alone can boost the car’s power and torque.
Stage 2: parts of the engine will be modified to work with the ECU update. This may include upgrading the intercooler, exhaust or air intake.
Stage 3: hardware upgrades are carried out. The vehicle will typically get a custom remap and be tested on a rolling road. It’s the most expensive of the options.
What does remapping a car do?
Remapping will affect how the car’s engine works by optimising:
Fuel injection
Ignition timing
Turbocharger boost
The fuel/air ratio
Accelerator response.
Remapping the software and fine-tuning the engine can increase a car’s power and torque output, maximising its overall performance by 20-50bhp or as much as 35 per cent. But this will vary between makes and models, and the type and quality of remapping done.
You should notice an improvement in handling and performance almost immediately after remapping.
What are the benefits of car engine remapping?
The benefits of car engine remapping include:
Better performance and power
Your car’s speed and power can be enhanced. With an enhanced throttle and faster engine response as you press the accelerator (high torque), your car may feel easier to drive. You’ll have greater confidence when overtaking too.
Improved fuel economy
If you go easy on the accelerator, remapping could help to increase your car’s miles per gallon (mpg) and overall fuel economy by optimising how much fuel is burned. You could save money and reduce your carbon footprint.
Easier towing
If you use your vehicle to tow a heavy trailer or caravan, remapping will mean it won’t have to work so hard when climbing or accelerating.
Changes aren’t permanent
If you’re unhappy with your car’s remapping, you can revert to the manufacturer’s specs.
What are the disadvantages of remapping a car?
There are potential downsides to remapping a car. These include:
Could invalidate the car’s warranty
If you get a remap that isn’t approved by the manufacturer or dealership, it’s likely to invalidate your car warranty.
Turbo engines benefit the most
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.
Increased running costs
Greater power can also mean more strain on the engine. Be prepared to have your car serviced more frequently. After remapping, your car’s major components, such as the clutch, may suffer greater wear and tear.
And you may need to buy higher octane fuel, which is usually more expensive. Fuel economy could also be reduced if your remapping focuses on greater power.
Changes aren’t permanent
Changes could get overwritten if your car software is further updated by the manufacturer, so you may have to pay for the remapping to be done again.
How much does remapping cost?
The cost of remapping your car will depend on the make and model, and the level of remapping you want done. A stage 1 remap could cost between £200 and £400.
A stage 2 remap could cost upwards of £550, while the higher stages of remapping and reconfiguring your engine could cost closer to £1,000.
Having your car tested on a rolling road to check the results of remapping will typically cost extra too. Make sure to compare quotes before you go ahead.
Does remapping affect insurance?
It may do. In car insurance terms, remapping is considered a car modification, even if it’s one you can’t actually see.
You need to tell your insurance provider if your car engine has been remapped. If you don’t inform them, it could invalidate your insurance 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 remapped.
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.
To see a list of possible providers, select ‘Yes’ when asked if your car is modified. Then, in the menu of options:
Select ‘Engine/Transmission’
Select ‘Chipped/Engine Management System.
FAQs
Where can I get my car engine remapped?
It’s likely that local garages to you offer remapping as a service – some will even come to your home. But it’s important to choose an authorised, reputable company. If work is carried out poorly, your engine could be damaged.
Will my car fail its MOT if it’s been remapped?
Provided it’s carried out by a reputable firm, a remap shouldn’t stop your car passing its MOT.
Is remapping bad for your engine?
As long as you use a reputable company to remap your car, your engine shouldn’t experience any damage.
A professional remapper shouldn’t allow changes that affect your car’s reliability. 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. So you might need to replace some vehicle parts 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.
Will my car be less fuel efficient if I get it remapped?
Not necessarily. In fact, 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’s 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.
Can remapping be reversed?
In most cases, yes. You can revert to the manufacturer’s standard settings, but you’ll have to pay a tuning company to do this for you.
If I sell my car do I have to tell the buyer it’s remapped?
Remapping is 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 remapping paperwork to show what’s been done.
Rory Reid is a car and technology expert. He serves as the main presenter on Auto Trader’s YouTube channel and was previously a host on the BBC’s Top Gear and its sister show Extra Gear. He was also a presenter on Fifth Gear.
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