Virtually all modern cars use an engine management system, which includes stock data. The chip within the ECU contains data that the car uses when determining fuel mix, power delivery, and turbo usage, but the majority of car models use a standard set of data that is used in all models of the same type. They must make allowances for all possible driving styles and even for those that use inappropriate petrol and oil. Car chipping replaces the stock chip with one that is tailored to your driving style and the conditions in which you drive most frequently.
Car chipping offers a number of benefits to the driver with the main benefit being that of additional power. Turbo diesels tend to be the type of vehicle that enjoys the greatest gains and car chipping a turbo diesel can provide as much as a 30% increase in BHP and torque.
The increased power means that you can enjoy quicker acceleration throughout the gears. You will experience fewer flat spots when a car tends to labour under acceleration. You will also enjoy improved fuel economy. By continuing to drive in the same way as you do already you could experience as much as a 25% increase in your mpg figures.