 How to increase the horsepower of your four-cylinder car. Four-cylinder engines are among the most versatile in modern vehicles, but you may be disappointed with the power they produce. Fortunately, there are a number of ways to pull more power out of the four-cylinder motor in your car or truck. Depending on your budget and skill set, you may choose to pursue a number of options, but be aware that many of these modifications may void your warranty. Maximizing your car's performance Properly maintain your vehicle. Although it's often overlooked as a way to pull additional horsepower from your car, properly maintaining your vehicle is essential to producing as much power as possible. Refer to your vehicle's owner's manual for recommended service intervals and ensure you're adhered to them. Make sure to change your oil every 3,000 miles or at your vehicle's recommend intervals. Replace your air and fuel filters periodically to ensure the unimpeded flow of air and fuel into the engine. Install a cold air intake. The four-cylinder engine in your vehicle is powered by compressing a mixture of air and fuel and igniting it. Because the level of compression your engine will produce is a constant' determined by the piston throw' you can produce more power by allowing for the flow of more air and fuel into the engine itself. To install a new intake, remove the stock intake tube and air box surrounding the air filter and replace it with an aftermarket one designed to increase the amount of air that passes into the engine. 2. Most aftermarket cold air intakes come with a cone-shaped filter that more efficiently pulls air from the atmosphere. Increasing the amount of air flow into your engine can also improve gas mileage. Many aftermarket intakes produce more noise than their stock counterparts. Most aftermarket cold air intakes come with a cone-shaped filter that more efficiently pulls air from the atmosphere. Increasing the amount of air flow into your engine can also improve gas mileage. Many aftermarket intakes produce more noise than their stock counterparts. Improve your vehicle's exhaust flow. As your engine ignites the mixture of air and fuel, it pushes the piston downward. The exhaust produced from this explosion must be evacuated from the cylinder chamber before more air and fuel can be injected. Replacing portions of your exhaust with larger diameter pipes will reduce the back pressure limiting the speed the exhaust may exit the engine. You may choose to replace the piping from the catalytic converter back referred to as a «cat-back» exhaust or all of the piping leading to the exhaust manifold. Kits can be purchased to replace however much of your vehicle's exhaust system you may choose. Forced induction applications like turbocharged vehicles will gain even more power from installing a higher flowing exhaust than a normally aspirated engine will. Have your vehicle's computer reprogrammed. In most modern vehicles, a computer controls a number of variables that affect how the engine runs. These computers are programmed from the factory to balance efficiency, emissions, reliability, power output and gas mileage. Reprogramming the computer to prioritize power can often free up horsepower without installing any new components. Search for companies that offer replacement computers for your specific vehicle online. You can either purchase a replacement or send yours out to be reprogrammed. Many companies sell programmers you can plug into the OBDII port of your vehicle to change the code in the computer you have. Swap out ignition components. For an engine to function properly, it needs air, fuel and a spark to ignite the mix. Old spark plugs and worn-out spark plug wires can prevent your ignition system from adequately detonating the air-fuel mixture. Your ignition components are often rated to be good for up to 100,000 miles, but replacing them with specialized aftermarket components can result in a more complete burn of air and fuel. 5. The more air and fuel your engine burns, the more power it produces. Worn-out spark plugs can even fail to ignite at all, resulting in a misfire. Larger diameter or more conductive ignition wires can reduce the time it takes for the spark to reach the mixture. The more air and fuel your engine burns, the more power it produces. Worn-out spark plugs can even fail to ignite at all, resulting in a misfire. Larger diameter or more conductive ignition wires can reduce the time it takes for the spark to reach the mixture