The amount of horsepower that is gained with a turbo is mostly measured in percentages. The percentages manufacturers quote on their products run between 35 and 60 percent. Some manufacturers do quote actual horsepower increases, and it is usually between 100 and 125 horsepower.
The amount of horsepower gained by installing a turbocharger or turbo kit widely varies and is dependent on the make/model of the car and engine, the equipment being installed, and the software being used on the computer. To gain optimum horsepower, assess the overall performance goal, read product descriptions and reviews to compare products before purchasing, and install the turbo kit according to manufacturer instructions.