Car Care for Better Mileage

Get the most mileage from a gallon of gas

Leonard Emanuelson / autoMedia.com

Remember when gas was less than $2 a gallon? While it would be nice to see those prices again, there are several easy and inexpensive things you can do to your vehicle to get the maximum miles per gallon, adding up to considerable savings over a full year of driving.

Reduce parasitic losses, maximize engine efficiency and change your driving style. There are three areas to consider when trying to attain or beat the EPA mileage claims for your vehicle—reducing parasitic losses, maximizing engine efficiency and changing your driving style. Don't look to any single item for a massive mileage increase. It's a game that requires discipline to find many small improvements that will add up to possibly a 10-15 percent overall increase in fuel economy.

What are the parasitic losses that affect fuel mileage? Anything that impedes the movement of the vehicle down the road such as (tire) rolling resistance, wind resistance, brake drag, wheel alignment and driveline friction. Some items like wind resistance are difficult to avoid. However, tire rolling resistance, brake drag, wheel alignment and driveline friction can all be optimized for a sizeable gain in mileage.

Tire Pressure

The first place to start any mileage self-help program is to purchase a tire gauge, keep it handy, and use it often. Most vehicle manufacturers recommend tire inflation pressures that are a compromise of comfort and safety. In the vehicles owners manual are listed a range of tire inflation pressures usually to compensate for loaded and unloaded conditions. One of the most important changes you can make is to keep your tires inflated at the highest recommended level. If the manual gives only a single inflation pressure, read the information on the sidewall of your tires concerning maximum safe inflation pressure and add 3-5 pounds of air making certain not to exceed the stated maximum inflation pressure noted on the tire. Keep a close eye on your tires for uneven tire wear. Greater tread wear in the center means too much pressure. If this happens, rotate the tires and slightly reduce air pressure.

Brakes & Alignment

Most brakes drag, but how much is too much? This varies from vehicle to vehicle and it's best left up to an expert at a brake or tire shop to decide, but the good news is that the inspections are usually free. Typical problems are calipers that are not fully retracting because they need to be replaced or rebuilt, or drum brakes that are incorrectly adjusted. While you're there, have the wheel alignment checked and aligned if needed. A modern car typically requires 10-20 road horsepower to maintain a cruise speed on level ground. Improper wheel alignment, a dragging brake or tire pressure that is too low could double the required road horsepower, cutting fuel economy by as much as 20 percent.

Synthetic Lubricants

So far the items we've talked about are free or are service procedures that you would perform to keep your car safe and operating properly. However, reducing driveline friction is going to require an investment above normal maintenance. The best way to reduce mechanical friction in the drivetrain is to replace petroleum-based lubricants with more expensive synthetic lubricants that have been proven to greatly reduce parasitic drag in engines and differentials. Several NASCAR teams have used zero-weight synthetic oils in their qualifying engines for years because of the horsepower it frees up. Expect to pay up to four times as much for synthetic as petroleum lubricants, however, you get some of that back in longer oil change intervals and longer engine life and easier cold weather starting. This is an area where you really have to do the math and decide if synthetics make sense for you.