All you need to know about "ECU remaps"
ECU remaps Guide
The ECU or Computer is what controls every aspect and function of your car.
Most cars built since 1992 and indeed many before that had a computer to monitor and manage the engine.
Now with the addition of catalysts and fuel economy requirements the computer has evolved into a complex system.
Before the computer arrived in car engines, a system of points and contacts controlled the spark timing and this timing was advanced according to the RPM of the engine.
It was crude but effective. A modern computer contains a complete map which not only set the spark according to engine speed, it takes into account many other factors.
For example the air flow into the engine and air temperature, the amount of unburnt oxygen in the exhaust and the throttle position and engine load.
The ECU controls the amount of fuel that goes into the engine and in modern tubo engines it can also control the turbo flow rate.
A default Original Equipment Manufacturers map has plenty of leeway built into it. A car has to cope with all manner of weather and driving conditions and needs to retain long service intervals and reliability.
If you are willing to reduce the margin of error manufacturers build in, or maintain your car with a shorter service interval there are potentially massive gains from a remap. Most remaps will still leave a wide margin for safety, but you can get custom remaps done that push the envelope as far as you wish.
On turbo cars there are substantial power increases on offer. (NASP cars will not really benefit from a remap unless a large number of other modifications have been done first.)
Off the shelf remaps are general and take the OEM state of tune up a notch or two. Custom remaps are engine specific, and, as no two standard engines are the same is generally much better than the off the shelf remap. If other modifications have been done, such as the fitting of a CAM or uprating the turbo, a custom remap is an essential.
NASP engines will generaly see gains of around 10-20% but turbo engines will usually see gains in the region of 30-50% (especially turbo diesel engines). At the upper end of these gains you should expect to have to uprate the fuel injectors and other major engine components.
New switchable remaps are available which allow the driver to select from an economy or valet mode to a sports/track day mode. These allow the driver to retain daily reliability and economy and effectively completely change the nature of the car at the press of a button.
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