Changes Under the Hood and Fenders That Increase Horsepower

In any engine increasing horsepower means increasing combustion. However, not every change to increase horsepower occurs under the hood.


Replacing drum brakes with discs will cut weight. Replace stock wheels with “rims” that are lighter. Before buying aftermarket wheels, know the weight of your stock wheels. Some custom wheels are heavier than factory wheels. There are tires that can improve aerodynamics.

Depending on how committed you are to reduce your car’s weight you can replace the stock auto glass with acrylic or plastic. If you’re willing to sacrifice passengers for performance, you can eliminate some seating.


To increase horsepower by 50%, install a supercharger (blower). Driven off the crankshaft a supercharger forces more air into the combustion chamber increasing the flow of fuel. A supercharger mounts to the engine and must be installed properly for maximum performance. Supercharger kits cost between $1,500 and $8,500.

Before shopping for a blower, you need to know your engine displacement and type. Whether you are installing the blower for the strip or street will determine the best type of supercharger for your purposes.

Root superchargers are commonly used for racing and tend to be cheaper than other supercharger types, but they are large and may require modifying your hood. Twin screw superchargers tend to be pricey, may not be street legal in your state, and generate both extra ponies and extra noise. As compared to Root and twin screw blowers, centrifugal superchargers offer greater efficiency and are the best choice if your car is a daily driver. Each type of blower comes in different sizes.

Air filters

Installing an aftermarket air filter is an easy modification. Secondary air filters allow more air into the engine than the air filters auto manufacturers install. Using TDot Performance as a point of reference secondary air filters prices start at $30.00 and go as high as $1,200. Being made of washable materials aftermarket air filters are reusable.

Cold Air Intakes

On the low-end, CAIs cost $129.00. On the high-end, they cost around $445.00. As with all the parts listed the make and model of your car will influence the price. As the name suggests Cold Air Intakes send only cold air into the engine. Cold air contains more molecules of oxygen thus increasing the rate of combustion and engine efficiency.

Performance Chips

In modern cars, the air-to-fuel mixture is regulated by a computer. Performance aka super chips enables the driver to circumvent factory settings. Installation involves plugging the chip into the onboard computer.

Installing a Super chip has some risks. Super chips can boost horsepower at the expense of overall performance and gas mileage. Emissions settings may be shut-off making your car illegal under emissions regulations and if your state checks emissions as part of a vehicle inspection your car could fail. Opening the ECU box to install a performance chip voids the warranty on a new car.