Car remapping explained

Car remapping is when you improve your car’s performance by modifying its engine control unit (ECU). But how does it affect your car insurance? Here’s everything you need to know. 

What is car remapping?

Car remapping, or ECU remapping, changes the performance of your car's engine.

But what is an ECU? Basically, it's your car's onboard computer and it's there to control things like:

• Fuel injection
• Air intake
• Ignition timing

So, by modifying or remapping your car's onboard computer you’re able to increase or decrease all these things. 

Do it right, and an ECU remap can boost your car's power and torque. But souping up your car isn't the only benefit. You can remap your car to improve its fuel efficiency and responsiveness, too.

Why should I remap my car?

That's up to you. If you notice your car's power isn't up to scratch, it could be worth looking at remapping your car.

You might want to remap your car if you're using it for high performance driving like rally driving or off roading.

Is car remapping legal?

Yes, remapping your car is legal. You just have to make sure your modified car still meets UK emission standards. Otherwise, you risk failing your MOT.

If you go to a certified professional, they’ll be able to ensure your vehicle is suited to remapping and that it stays roadworthy. 

Once your car’s been remapped, it’s a good idea to get it regularly serviced, too. This is because parts like your brakes and suspension are under more strain. By getting an experienced eye to take a look, you’ll have peace of mind that your car’s in tip-top condition. 

What are the stages of remapping?

There’s no official rule book when it comes to car remapping, but most people break it down into 3 stages. 

They’re probably best understood like levels. The first stage involves a light modification to your car’s ECU, the second is more moderate, and the third is the most severe change.

Let’s dive a bit deeper.  

• Stage 1: This is when changes are made to the ECU, but the hardware is left as is. While it might be a lower level of modification, it can up your engine’s horsepower by 15 to 30%.
• Stage 2: Alongside making software upgrades, stage 2 involves physical changes, too. It usually entails moderate changes to hardware, like installing a new intercooler or exhaust system.
• Stage 3: The most hardcore level of car remapping that calls for intricate mechanical work to modify both the software and hardware. It can make a big difference to your vehicle’s performance. But, you might need a professional assessment to check whether your car’s good to go on the road.

Remember: These stages are just guidelines - they haven’t been put in place by a governing body. So, it’s always worth checking with your mechanic or tuner to see whether they’re singing from the same hymn sheet.  

What are the benefits of car remapping?

If a specialist does your remapping, it can have a few benefits including:

• Improving your car's performance: Your car could have more speed, power and torque after remapping. So it might be more responsive when driving up hills or overtaking for example.
• Improving your car's fuel efficiency: 'Eco-tuning' is a type of remapping. This is when your car is remapped to improve its miles per gallon (mpg).
• Improved towing: Because you can improve your car's power, towing becomes a lot easier.
• Better driving experience: remapping your engine means you could have a smoother and quicker response from your car.

What are the disadvantages of remapping a car

There are some disadvantages of car remapping:

• It can affect your engine: If you're remapping your car to increase its performance, it can affect the engine. You might find that parts of your car wear out more quickly and need to be replaced.
• It could void your car's warranty: If something goes wrong with your car after you've remapped your engine, your car's warranty probably won't cover it. We'll talk about this in more detail later.
• The car might not meet emission standards: Some remapping can mean your car doesn't meet emissions standards, so you could fail your MOT.
• Could decrease your car's resale value: Car remapping for performance purposes could indicate engine wear and aggressive driving. Both of these affect the car's mechanics so potential buyers might be put off.
• It might cause software issues: If your remapping isn't done by a professional, you might find that your ECU is glitchy. Your engine's performance could be erratic or fail completely and your dashboard warning lights could come on randomly too.
• You might need to switch fuels: Because your car will have a higher performance, you might need to switch to a high-octane (or high-efficiency) fuel.
• You'll have to reset your custom settings every time you have a service: Car software is updated fairly frequently, so every time your ECU gets a maintenance service you might have to redo your custom settings.
• It could affect your car insurance: Remapping is essentially modifying your car, so you might need modified car insurance. This means your car insurance could be more expensive. We'll look at this in more detail shortly.

How much does it cost to remap a car?

Remapping costs vary depending on the car and its make and model. If you're interested in getting your car remapped, you can compare garages with us and get a quote.

At a glance, you can expect to pay:

• £200-£400 for most vehicles.
• £500+ for high-performance or luxury cars.

According to FixMyCar, these are the average remapping costs for popular makes and models of car:

*Figures taken from FixMyCar

How do I find a reputable remapping specialist?

You can get your car remapped by a professional tuning service or a garage that specialises in remapping. Here are a few options:

• Specialist tuning companies. There are some national remapping chains as well as performance specialists.
• Independent garages or car dealers.
• Mobile remapping services. These companies come to your home or work and remap your car.

Search for your nearest service online and be sure to check their reviews. Use sites like Trustpilot or scour their Google reviews. Word of mouth recommendations are good too.

It’s also important to check their credentials. They should stick to regulations, for example, emission standards for MOTs. And, any good remapping service should be certified by the Institute of the Motor Industry (IMI).

Finally, you’ll want to ask questions and make sure the work they're offering is customised to your car, rather than a generic upgrade.

Car insurance for remapped cars

It's pretty straightforward to get a car insurance quote with us for a remapped car. Here's how you do it:

• Enter your car's make and model
• Under 'further details' select 'yes' when you're asked 'does the car have any modifications?'
• We'll then ask you 'what modifications have been made to the car?', scroll to 'engine and transmission'
• Select the type of remapping that your car's had.

Does remapping affect my car’s warranty?

Yes, remapping can affect your car warranty. But, it depends on the vehicle’s manufacturer and the specific terms of your cover. 

It’s not uncommon for a car’s warranty to be voided altogether if a remap is detected. And while you might think a quick fix is to reverse any changes you’ve made, that might not be enough. 

Manufacturers can usually tell when the ECU has been tampered with - even if it’s been changed back to factory settings.

So, if your car is fresh out of the garage, or you have an extended warranty, it’s worth checking your documents before getting to work on a remap.

Do I need to tell my insurer if I remap my car?

If you take the leap and decide to remap your car, it’s crucial you tell your insurer. Whether you’ve opted for a light, stage 1 remap or you’ve gone all the way to stage 3, the same rule applies. 

In the eyes of car insurance providers, remapping your ECU is a type of car modification. By keeping quiet and not declaring a modification, you risk invalidating your cover. 

But, if you’re upfront, you’ll know where you stand and can get back behind the wheel knowing your policy is watertight. 

Expert quote:

“Declaring modifications is crucial when it comes to car insurance - and remaps are no exception. While you might not want your premium to go up, the alternative is having your cover invalidated entirely. And if you need to make a claim later down the line, you could find yourself in hot water.” MCR

Does remapping make car insurance more expensive?

Yes, remapping can make your car insurance policy more expensive. And, in some cases, your insurer could refuse to cover you altogether. 

Insurance is all about evaluating risk. And changing your car's original engine settings is quite risky. For example, upping your engine's power means you can accelerate more quickly.

So, in an insurer's eyes, you're more likely to get into an accident.

Car remapping could also cause your car more damage if it's not done correctly. All this could mean car insurance for a remapped car is more expensive - or a little trickier to get. 

Frequently asked questions