In this business, one of the most common misconceptions i hear, concerns fuel efficiency. Most people assume that Fuel Efficiency equals better gas mileage, and lets face it, thats an easy assumption to talk yourself into with todays high gas prices. For most people, when they buy a performance part that promises better fuel efficiency, the placebo effect kicks in and they might believe they are getting that extra mpg, but in reality, its just not true.

Let's use a Green Drop-In Air Filter for example. The common sales point is better gas mileage and more power. While you can expect to see a small hp gain, your gas mileage will not increase, but you get your increase in power through fuel efficiency. If you stop to think about this, it makes perfect sense. You are adding more air to your motor, which in return, tells the ECU to supply a little more fuel. Due to the increase in air within the cylinder, more of the fuel going into the motor is burned, thus creating a more complete combustion cycle. It explains the power side of things, but more fuel will never equal better gas mileage.

With that said, Fuel Efficiency is nothing more than the % of combustion that occurs within each cylinder on the firing stroke. As tuners striving to squeeze every bit of power out of our engines that we can, fuel efficiency is something that we need to consider when bolting on parts to our car. We can throw parts at it all day long and we might see some more power. But what if we add those same parts, and then add a few more that promote fuel efficiency. We will see the total hp gain of each part increase, due to the more complete burn of the fuel in the chamber. For instance, we recently added a SUN Auto Hyper Force Voltage System to a customers Mitsubishi Evo 8, and saw gains of almost 17hp. Why, because it burned almost every droplet of fuel sprayed into the engine.

Pretty simple isnt it. Unfortunately, it is one of the most overlooked areas among new tuners and enthusiasts. I hope this helps explain what fuel efficiency really means when a company tells you that a particular product offers that, and just maybe, you can tell them what it really means. You guys are going to mod your cars, you already expect a small decrease in gas mileage, so, you may as well make it count. I could go on forever about this subject, but you all get the idea.