What is engine remapping and is it worth it?
There are many advantages to remapping your vehicle. We discuss what remapping actually is, how it affects your vehicle and what the potential upsides and downsides may be.
Engine Control Unit
Modern vehicle engines are controlled by a computer known as the Engine Control Unit (ECU). This tiny computer controls aspects of the engine such as ignition timing, air/fuel ratio and boost pressure. By adjusting these settings the vehicle can be altered to increase either performance or economy, or sometimes both.
Remapping, often called Chipping, is when third party software is installed onto the ECU to replace the manufacturer’s default software. This new software can have customised settings to get the most out of the engine and can often be tailored to each specific vehicle.
It is usually installed by connecting a laptop to the vehicle’s OBD serial port, which means it can be done quite quickly and non-invasively. Older vehicles had to have their engine’s computer chip completely removed and replaced with a new chip that has the new software already on it. This is why it used to be called chipping.
What effects can a remap have?
By changing the ECU software, the engine can perform a lot closer to its own maximum capabilities - often by increasing horsepower and torque by 20% or more! By default, most vehicles have their performance intentionally dialled down when they leave the factory for a multitude of reasons. Often this can be to meet emissions regulations, or economy or noise regulations.
Additionally, vehicles always come with a warranty, and the last thing the manufacturer wants is to have to rebuild or replace damaged engines. For that reason the performance is always kept well within the capability of the engine.
Most manufacturers also tend to release facelifted versions of each model of car they produce after a few years before they release completely new versions. By adjusting these ECU settings themselves on the facelifted models they can quickly and easily increase the vehicle’s performance figures, making them more desirable without much or any additional engineering required.
Is a remap just a software change?
Yes. Remapping is often called Stage 1 tuning and comes as part of many stages offered by the tuning company. Stage 1 is nearly always just a simple ECU software change. Stage 2 and beyond will usually comprise of further software changes as well as additional hardware, such as a new exhaust system and high-pressure fuel pump. Stages 3 and 4 will often involve upgrading the vehicle’s turbocharger or supercharger. Later stages tend to require more invasive work and provide fewer gains in performance per pound than the first stage.
Is remapping dangerous or harmful to the engine?
Changing settings that affect the control of an engine can have harmful effects, it all depends on who wrote the software, and how the vehicle tuner configures it to the vehicle. For this reason we would never recommend installing your own software, or software from an unverified company. There are specialist tuning companies that write ECU software and they will usually test and tweak it for a year or more on many vehicles before making it available to the public. Going with one of these companies means the software you have installed is most likely going to be safe to use, but always check reviews first.
Will remapping affect my warranty?
Because the software being installed is rarely written by the vehicle’s manufacturer, it will most likely void any warranty you have on the vehicle. At the end of the day it’s not the manufacturer’s decision to push the engine to its limits (or beyond) and if something were to go wrong you could end up paying for an engine rebuild yourself. The software company that wrote the map will also be unlikely to cover these costs too. That's why it’s so important to go with a trusted company that has a lot of experience.
Is remapping really just for performance cars?
Remapping can increase both performance and economy in most types of vehicles. Even a car with a 1 litre engine can receive good power gains from a remap, especially if it has a turbocharger.
Most modern cars these days have a turbocharger (or supercharger) fitted to the engine. An engine works by mixing compressed fuel with air and then igniting this mix inside its cylinders. Turbochargers and superchargers increase the fuel compression therefore allowing more fuel to fit inside the cylinders before igniting. More fuel equals more power. It is more fuel efficient to increase power this way rather than just having a larger engine to begin with. Emissions tend to be much lower too. This is why we are seeing more 3, 4 and 6 cylinder engines and fewer 8, 10 and 12 cylinder engines.
Remapped vehicles get the most benefit when there is a turbocharher or supercharger installed as the main changes that are made to the software are fuel compression, fuel/air mix and boost pressure. Remapping a naturally aspirated engine (one without a turbocharger or supercharger) means there is little that can be configured. This means you will likely not receive much of a power gain.
Will my economy increase as well as performance?
That all depends on how you drive. In theory, many remapped engines are capable of achieving the same economy as the same engine in pre-remapped form, and sometimes can even be more efficient. The big caveat though is that there is usually the opportunity to extract increased power from the engine. The majority of drivers - especially ones who have gone to the effort of getting their engines remapped - will most likely make use of this extra power, by accelerating more quickly when the opportunity arises. As a result they will likely use more fuel than before. After all, what is the main reason most people look for a remap? For increased performance.
Are there any other benefits besides performance and economy gains?
There can be, yes. Depending on the map you have installed, some vehicles will benefit from a valet mode, and immobiliser mode, which you can activate with a switch device. Immobilser mode means the car will not drive even if a thief manages to steal your keys and start the car. Without the switch, the car will simply not be driveable.
A valet mode can be very useful too. This is designed to be set when you hand your car over to a valeting company, or someone you do not want driving the car long distances but may require access to move the car in some way. The valet mode limits performance and top speed dramatically, for example by having a top speed of 10 or 20mph. This is great for peace of mind.
Similarly, many companies that have a fleet of vehicles for employees often have special maps installed that limit their vehicles to 70mph. This prevents employees from breaking the speed limit on motorways. So a remap is not necessarily just for people who want to drive faster.
Will I need to use a higher grade fuel with my remap?
Potentially, yes. It all depends on the type of map you have installed. Usually, you will safely be able to use the same fuel as before. (For more information on the different types of fuel, see our article Our guide to different types of fuel - Petrol vs Diesel). However, some performance cars may be mapped to a specific fuel grade. (ie 99 RON Octane in petrol cars or 55 CN Cetane in diesel cars), which means the car will perform to its optimum if you stick with that exact fuel grade. Damage will rarely be done to the vehicle if you use a lower grade fuel, but this will often result in a jerky drive and poorer performance, even more so than before the remap was installed. So always discuss the recommended fuel type to use with your tuner when getting your vehicle remapped.
Will my insurance premiums go up?
As with any vehicle modification, you will have to declare the remap with your insurance company. Whether or not they accept the modification will be down to the specific insurer you have, but it’s very common to have an ECU remap. They will usually ask you what the power increase is in percent, and then let you know if they are happy to continue insuring you to drive the vehicle, and what the increased cost will be. There’s often an admin fee to make a policy change too, so bear this in mind.
If the insurance company is unable to continue insuring you, you’ll need to cancel and find another insurer that is. This means paying a cancellation fee and potentially losing any no claims bonus you may have accrued that year.
We would never recommend keeping the remap a secret, firstly because it’s illegal, and secondly because if you need to make a claim and the map is discovered then your insurer may invalidate your policy and refuse to pay out.
Can I remap an electric car?
With electric cars becoming more and more prevalent, the budding question now is whether or not they can be remapped in a similar way to their combustion engine counterparts. The short answer, however, is... no. Well, not yet anyway. Mainly because electric vehicles are so new there aren't enough third-party ECU tuning companies that have come up with reliable solutions yet.
Of course, all the fundamentals behind remapping a petrol or diesel engine are no longer applicable, but that doesn't mean that parameters cannot be changed for an electric motor. Electric vehicles have a very different power delivery to what we're used to. There are no revs or gears, and maximum torque can be achieved instantly. For the purposes of comfort and efficiency, though, this will be dialled down in retail vehicles. After all, very few people want 100% power when pulling away at the lights. (Seriously, they don't. It's not practical, or safe for that matter.)
But in theory, these factory settings could be altered, allowing more available power more quickly. This would result in a performance gain, but naturally have an adverse effect on range, drivability, as well as the overall lifespan of the motor.
It's worth remembering, also, that these companies have had years to test and fine-tune their ECU software on petrol and diesel vehicles. EVs simply haven't been around long enough yet. I would certainly bet that there are a plethora of ECU tuning companies with EVs being tested as we speak though, so if you're a keen vehicle tuner, I'd watch this space, as I'm sure that electric engine remapping will be a viable option in the future. After all, where there's demand, there is bound to be a market for it.
We think remapping a vehicle has many benefits, especially if your vehicle is already out of warranty. Always research the remap company well before letting anyone install third-party code onto your vehicle’s ECU, and always get an insurance quote beforehand as well. I’ve personally had my last two cars remapped and would always look to do it again on future cars.
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