What remapping is, in plain words

If you are not into cars, words like "remapping", "chiptuning" or "Stage 1" can sound confusing. You do not need to be a mechanic to understand what happens. Let's start from the beginning.

The car's "brain"

Every modern car has a small computer that controls the engine. It is called the ECU (engine control unit). Thousands of times a second it decides how much fuel to inject, how much air to let in and, on turbocharged engines, how hard the turbo should "blow".

To do that it follows instructions: tables of numbers written by the manufacturer. These tables are called maps.

What remapping is

Remapping means changing those maps. No part is added and the engine is not opened. We connect to the ECU, usually through the same socket a garage uses for diagnostics, read its software, adjust it and write it back.

The word "chiptuning" is left over from the days when the software sat on a chip that was swapped by hand. Today it is all done electronically.

Why the engine has headroom

A manufacturer sells the same car all over the world: in countries with poor fuel, extreme cold or heat, to drivers who skip servicing. So the engine is set up with a generous safety margin. Often the same engine is sold in two or three versions with different power, and the only difference is the software.

A good remap uses part of that margin — not all of it.

What you gain

Easier overtaking and hills. The engine pulls harder at the revs you use every day.
More power and torque. On turbocharged engines the difference is large, on some up to about 50%. On engines without a turbo it is small, around 8–10%.
On some diesels, lower consumption, up to about 10%, if you drive as before. That is the Eco remap.

How much your own car gains shows on the dyno, measured before and after.

What the "Stages" mean

Eco: a remap aimed at economy and smooth driving.
Stage 1: software only, on a car as it left the factory. The most common choice.
Stage 2 and up: the software is written for a car that already has upgraded parts, such as the exhaust or the intercooler.

What a dyno is

A dyno (dynamometer) is a machine with rollers in the floor. The car drives onto it, is strapped down and "runs" on the spot while the machine measures how much force reaches the wheels. We measure before, to check the engine is healthy, and after, so you see the difference on a graph. Our dyno is four-wheel drive, so it measures 4x4 cars correctly too.

To see how it works, read A day on the dyno.

What to watch out for

The engine must be healthy. A remap does not repair faults, it shows them up. That is why we check first.
More power means a little more wear, mainly on the clutch and the tyres. A conservative remap keeps it small.
Warranty and insurance. If the car is still under the dealer's warranty, talk to us before deciding. Tell your insurer where required.
It can be undone. We keep a copy of the original software so it can be restored.

If something specific worries you, Is remapping safe? answers in detail.

A short glossary

ECU: the computer that controls the engine.
Map: a table of values inside the ECU, e.g. how much fuel for each throttle position.
Power (PS / hp): how fast the engine can do work. It mostly shows at high revs and top speed.
Torque (Nm): the "shove" you feel when you press the accelerator, e.g. on a hill. For everyday driving it matters more than horsepower.
Revs (rpm): how fast the engine turns. You see them on the rev counter.
Turbo: a "fan" driven by the exhaust that pushes more air into the engine. More air means more fuel can be burned, so more power.
Boost: how hard the turbo pushes air in.
Intercooler: cools the air coming from the turbo, because cool air holds more oxygen.
Naturally aspirated engine: an engine without a turbo.
Knock: uncontrolled ignition of the mixture inside the engine, which strains it. The ECU detects it and cuts power to protect itself.
Octane: how well petrol resists knock. 98 and 100 resist it better than 95.
DPF (diesel particulate filter): a filter in a diesel's exhaust that traps soot.
EGR: a valve that sends a little exhaust gas back into the engine to lower emissions.
AdBlue: a fluid sprayed into the exhaust of some diesels to lower emissions. On DPF, EGR and AdBlue see what is allowed and what is not.
DSG / automatic gearbox: a gearbox that changes gear by itself. It has its own computer (TCU), which can be remapped too.
Clutch: the part that connects the engine to the gearbox. If it "slips", the revs rise but the speed does not.
Limp mode: when the ECU sees something wrong, it cuts power to protect the engine.

Next step

See what is available for your own car in the car finder or request a quote. If you have questions, just ask — no question is a silly one.