There are several ways to increase horsepower while simultaneously increasing fuel economy. Stock engines are fairly restrictive in terms of their air/fuel delivery, ignition and exhaust systems. Proper maintenance, combined with some relatively simple and inexpensive modifications, substantially improves horsepower and fuel efficiency.
Install new spark plugs, spark plug wires and change the oil. Spark plug tips become corroded over time, reducing the plug's ability to deliver a proper spark. Even if the plugs are in good shape, corroded spark plug wires won't deliver electricity to the plugs. Changing oil also makes the engine operate easier, freeing up horsepower and improving fuel mileage.
Upgrade the stock air filter element with a quality aftermarket filter. Stock air filters are made from material which severely restricts the ability of air to pass through them. That forces the engine to work harder and burn more fuel to draw air through the filter. Aftermarket air filters are as efficient, if not more so, than stock filters. They help air pass more freely through the filter to the engine.
Upgrade to an electronic ignition system. This is especially helpful for older cars with a mechanical points distributor. Simply unbolt the existing distributor, remove it and install an electronic one. Consider upgrading to a more powerful ignition coil. These upgrades will ensure a strong spark reaches the air / fuel mixture.
Upgrade your single exhaust pipe to a dual exhaust system, if applicable. An engine must receive fuel and air and expel exhaust gases. A single exhaust system causes the engine to use power to expel the exhaust gases. Adding a second exhaust pipe will help the engine "breathe" better, increasing horsepower and fuel mileage.
Replace the exhaust manifolds with exhaust headers. An exhaust manifold routes the exhaust gases from each cylinder into a single pipe, where the combination of exhaust gases must travel through a series of twists and turns before finally reaching the exhaust pipe. This requires the engine to push the gases together, robbing the engine of power and using excessive fuel. An exhaust header uses one exhaust pipe for each cylinder, meaning the engine no longer needs to combine the gases from each cylinder.
Replace the mechanical fan with an electric one, if applicable. Mechanical fans bolt directly to the front of the engine and use the engine's power to turn the fan blades. Replacing the mechanical fan with an electric unit eliminates the drag the mechanical fan places on the engine, increasing the engine's output to the drive wheels. Electric fans bolt directly to the radiator and are easy to install.
