Tuning a turbo

Modern engines are managed by a computer which typically measures the air temperature and flow rate and delivers a matching amount of fuel to prevent the engine from running too rich or too lean.

Modern engines also sense the amount of oxygen left to see how efficient the burn was and adjusts the fuelling and ignition to match.

In a turbo engine you will find that the computer controls more aspects of the engine including the wastegate control and allows the turbo to produce differing amounts of boost pressure under different load conditions.

Changing the settings in the computer ie: Remapping it will change the characteristics of the engine. Most turbo engines are stronger than they need to be for reliability which gives a very nice margin of possibility to the tuner.

The two main remaps are off the shelf, where a company develop a range of settings that work on wide range of standard engines and the custom remap where the car is put on a rolling road and the engine is tuned on an individual basis.

There is a wide cost variation between these 2 options and for most users who want a modest 40-60bhp power boost and need to retain reliabilty the off the shelf option works the best. If you modify other parts of the car then a custom remap is the only way you can really maximise the benefit of these modifications.

To get the most power from a turbo a remap is essential. When looking to increase your turbos capacity go with a ball bearing turbo as these have less internal friction and as a result spool up a lot more quickly, spin at a faster rate and last a lot longer than thrust washer types.

The characteristics of a ball bearing turbo include less lag, more power at top speeds, quicker pickup across the rev range and greater reliability. If you are looking at replacing a turbo on your engine make sure you upgrade the internals.