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Remapping: what you need to know

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November 1, 2018
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This article explains what happens during a remapping service, the pros and cons of getting it done, and how to know if your car has already had it.

What is remapping?

Remapping is a process of altering your car engine’s computer, which is better known as an engine control unit (ECU). The ECU is programmed to manage functions such as the fuel injection, sensors, air flow, etc. By changing or overwriting this program with new software, the functions can be customised and the performance of your car can be improved.

What are the benefits of remapping?

Car manufacturers are known to program their models’ ECUs so that they are not performing at peak efficiency. This allows them to release a sportier model with a more efficient engine by simply reprogramming the ECU and making small design tweaks. Remapping your car means you can get the most out of your engine – improving performance, fuel efficiency and responsiveness.

Improved engine performance is another way of saying more speed and more power. The increase in horsepower you’ll get from remapping depends on what sort of engine you have. For example, you could get an increase of as much as 40-50bhp (brake horse power) for a turbo engine. It may be lower in other engines. Many remapping services also boast an increase in torque of up to 80nm (Newton metres). In other words, it’ll feel faster!

In regard to improved fuel efficiency, this really depends on how you drive your car. Rushing through gears, sudden and fast acceleration, speeding and sudden braking can have a negative effect on your fuel economy, increasing consumption up to 40%. While this is true whether you remap your engine or not, the combination of remapping and smooth driving will offer better fuel efficiency than good driving on its own.

Are there downsides to remapping?

If you have a fairly new car, one of the biggest downsides is that remapping your engine will most likely invalidate the manufacturer’s warranty. You could remap your car once your warranty expires, or you may be willing to take the risk – it’s up to you.

It is possible for your engine to be damaged by remapping, but the chances of this happening are very slim. However, most reputable remappers will offer a lifetime warranty on the software they install on your ECU anyway.

Remapping may increase your insurance premium, but you can find a good deal by using a specialist insurer like Adrian Flux, who offer insurance tailored for owners of modified cars. You must declare that your car has been remapped regardless of the insurer you choose (or your policy could be invalidated).

Driving your car after its been remapped will feel different. Most drivers will adapt after a few trips in a freshly tuned car, but for some drivers may not enjoy the new driving experience as much as they had hoped. Thankfully, remapping is completely reversible!

How do I know if my car has been remapped?

If you suspect that second-hand car has been remapped, but the previous owner nor paperwork mention it, then it can be hard to tell for sure. Although some remapping services leave a sticker on the ECU, this is the only visual clue that changes have been made.

You could refer to your car’s user manual and compare the acceleration and performance of your car currently with the figures in the booklet. However, if you really feel like the ECU could have been altered, you should take it to a remapping service or manufacturers’ garage where someone can review the software. This will likely cost you money, but if you’re in any doubt, it’s worth doing – if you don’t declare remapping to your insurance provider it could affect any claims you make if it’s later found to have been tuned.

Is remapping the same as ‘chipping’?

‘Chipping’ and remapping are both methods used for improving a car’s performance. Much like the inside of your laptop or mobile phone, an ECU comprises a motherboard and microchips. While remapping changes the software that the unit runs, ‘chipping’ involves physically replacing the main computer chip with a new, pre-programmed one.

Around 2000, cars were becoming more computerised and manufacturers started to include an access point in their ECU designs. The access point, known as an on-board diagnostic (OBD) port, allows mechanics to connect an external computer or device to the ECU and investigate why certain systems aren’t working as they should. The OBD port is also used for remapping engines.

‘Chipping’ is a more risky process than remapping as it requires the mechanic to open the engine control unit, leaving it vulnerable to damage. Since OBD ports became mandatory in Europe for petrol cars in 2001 and diesel cars in 2003, ‘chipping’ is usually saved for models that pre-date this era.

If you enjoyed this article, check out our guide to the nine top car modifications and how they affect your insurance or our top 10 cars to modify.




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