There are several different steps that can be taken to with your engine to increase horsepower. Many times manufacturers make compromises that may make the vehicle more roomy or comfortable, but do not provide the best performance. By making some alterations to your vehicle it is possible to add horsepower onto the current output. Some alterations can be inexpensive and easy to make, while others are difficult and will cost more.
The Computer Chip
The ROM chip that controls the engine control unit may affect the performance. This is not necessarily the case for all cars but for some it is possible. The best place to find these chips is from aftermarket performance dealers. Try to read about the chips that are of interest, as some may claim to increase horsepower but actually don't.
Decrease Air Resistance
The easier air can come in, the more horsepower that can be achieved. Air resistance can take up horsepower and a polished intake manifold can be used to decrease the air resistance. Reduced intake piping and larger air filters can improve the flow of air so that there is less resistance.
The back pressure can make it very difficult for the exhaust to leave the cylinder. A muffler that has a lot of air resistance or an exhaust pipe that's too small can increase the back pressure. Most high performance vehicles will use free flowing mufflers, larger tail pipes and system headers to eliminate any possible back pressure.
Head and Cams
A new head that has an increased number of valves on the cylinder can increase horsepower. The cylinders that come with the car normally have an exhaust valve and an intake valve. More valves will help air flow. Performance cams can also help to increase the air flow.
A great way to increase horsepower is to get more air into the cylinder. Ultimately the more air in the cylinder, the more fuel that can be used and converted into energy. Superchargers and turbochargers can cram even more air into the cylinders. Turbochargers are becoming fairly standard on smaller cars. There are many aftermarket superchargers that can be added.
Cold Air Intake
Cold air into the cylinder will compress easier. The warmer the air, the less it will expand when it is ignited. Turbochargers and superchargers will contain an intercooler which will cool off the air before it goes into the cylinder.
Weight does increase performance, which in turn helps increase horsepower. Lightweight parts can make all the difference. Lighter pistons will require less energy to move which in turn allows the engine to rev even faster.
Increased displacement is one of the most difficult ways to increase performance. If you are going to spend the money to do this, then think about getting a high performance engine for your vehicle. Getting a new engine may be cheaper and easier to install.