A turbocharger can add up to 70 to 150 horsepower. The power it adds can increase or decrease depending on whether it is a single turbo or a twin-turbo. If it is a single turbo, it can add up to 30 to 45 hp. While a twin-turbo adds somewhere from 100 to 250. However, you must ensure that your car is modified to accommodate the additional power being added to it.