Gas Mileage

Gas mileage is always a big one, and all you ever hear is how to alter your driving style to increase your gas mileage and never about modifications to the vehicle. Personally, I tried driving very conservatively, and then stomping on the gas when I felt like it, and my gas mileage never changed. In order to truly increase gas mileage is to do modifications on the engine. The most important thing is using less fuel to create the same amount of power. Let's look at some ways that this is possible.

1. Increase the compression ratio to something over 9.5:1 if the vehicle is not already there (don't touch compression if your vehicle is supercharged or turbocharged). Increasing the compression ratio will create more power with less fuel by compressing the fuel more, making a more complete burn. The increased compression ratio also increases torque and horsepower by a considerable amount. If you need higher octane gas, you can go back to lower octane by retarding the ignition timing, but the gained power will be lost (not the fuel economy though, that stays).

2. Let your engine breathe better. Putting a less restrictive muffler on with no other modification isn't going to do much because there is only a certain amount of air able to go into the engine. Lets say your stock air intake allows 200 CFM of airflow, and the stock exhaust allows 300 CFM. If you add an performance muffler that flows 800 CFM, but your catalytic converter only allows 500 CFM and the stock exhaust manifold allows 400 CFM, you are only going to be flowing 400 CFM out the exhaust. But your air intake is stock, so really your total flow is still only 200 CFM. So in order to allow your vehicle to breathe easier, you need to increase the CFM of every breathing component of the vehicle.

3. Get rid of that belt driven radiator fan. Really, these things are out-dated, I don't know why they keep putting them on cars. Get an electric radiator fan instead. They do not put any load on the engine, and they flow more air at idle, when you need the cooling the most.

If any modification requires bigger fuel injectors or more fuel, then it will not increase fuel economy. DO NOT get this modification if you want good fuel economy.