What Can I do to My Engine to Improve Gas Mileage?

As the price of gas spiraled out of control in late 2008, the main question on the minds of many motorists was "What can I do to my engine to improve gas mileage?" There are some very effective modifications you can make to most diesel and gasoline engines that will offer a significant increase in gas mileage. One of the easiest and most efficacious modifications you can make however, are not to your engine, but to your driving style.

Keeping the pressure light with your right foot will offer dramatic increases in fuel economy. For example, keeping your freeway speed under 65mph vs. traveling at 75mph can be worth about a 15% improvement in mileage, depending on your vehicle and the road.

Looking ahead to anticipate stops will allow you to get off the accelerator pedal early, and delay applying your brakes until it is necessary. Braking too early merely takes stored energy and converts it to heat. You have to burn precious fuel to add that speed back. It's better to keep from wasting it in the first place.

What if you're aware of what you can do behind the wheel to save fuel, and are doing all you can? What modifications can you make to your engine that will help you to save fuel? Are there any, and are they cost prohibitive? After all, you wouldn't want to spend a fortune doing things to your engine, only to save a few dollars in fuel cost. Determining the break-even point, or calculating the return on your investment will be predicated on the price of fuel. Obviously, the more expensive a gallon of gas, the faster your engine modifications will pay off.

Thankfully, many of the most effective things you can do to improve gas mileage are also the easiest and least expensive. One of the most popular and easy engine modifications is the addition of a cold air intake. This simply replaces the factory air box, air cleaner assembly , and plenum tube with a whole new system. The new system will be less restrictive so the engine can breather easier. In addition, it let's the engine breathe cooler air from outside the hot engine compartment. All else being equal, cooler air is denser, meaning the engine gets more air with every breath.

Why don't the factories just install this type of air intake in the first place? In one word, noise. Typically, the less restrictive intakes do away with resonators and baffles designed to muffle intake tract noise. This lessens resistance and increases flow, at the cost of additional sound emanating from the engine compartment. The good news is that not only will such intakes give improved mileage, they'll usually get you better throttle response and more power too. So, not only will your vehicle get better gas mileage, it will drive better as well.

Another very common modification for both gasoline and diesel vehicles is the performance exhaust system. Such an exhaust system normally replaces the exhaust from the catalytic converter or DPF (on diesel engines) rearward, hence the name "cat back exhaust" that they are known by. They get improved performance and mileage by removing restrictive kinks and bends in the factory exhaust and using larger diameter tubing and less restrictive mufflers.

All this adds up to more flow out through the exhaust. Since engines are basically air pumps, anything you can do to make it easier to get air into, and then out, of the engine results in better performance and mileage. The factories have too many regulations and cost restrictions to fit these exhaust systems as your vehicle left the factory. Most of them are stainless steel, which is many times more expensive than the aluminized tubing used in your vehicle's factory exhaust.

Performance exhaust systems are relatively easy to install and easy on your budget. Those tow characteristics, coupled with the nice exhaust tone they generate accounts for their tremendous popularity.

One last thing you can do to your engine to improve mileage is to change the factory power train control computer programming. The factory computer, also known as the ECU or ECM has it's hands in all manner of your vehicle's operation from the fuel mixture and turbo boost, to transmission shift points and torque converter lockup.

Depending on what you drive, there is a huge potential here for positive change. Drivers of diesel pickups can see 20% mileage improvements with the simple addition of a performance ECM programmer. With most diesel engines there is also the potential for tremendous power and torque increases; on the order of 100 – 200lb-ft of additional torque, actually!

Most such devices offer the ability to change the engines programming to one of several presets, each optimized for a different function. For example, you may want to have one for towing, one for general driving, a setting to improve your mileage, and one for performance driving. These programmers work well on both gas and diesel engines, however it's the diesels where such modifications really excel. The extent of any improvement you'll see really depends on the factory ECM program and your driving style. Some engine and computer combinations simply offer more room for improvement than others.

Those are three relatively quick and easy things you can do to your engine that can make significant improvements to not only your mileage, but your vehicle's driveability too. Their effectiveness, affordability, and easy installation account for their tremendous popularity.

Discover more quick and easy ways you can improve your vehicle's gas mileage, power and general driveability. They are revealed at the insider's guide to Increasing Diesel Mileage. Don't worry, there is plenty there for gasoline fueled vehicles too.