High Gas Mileage Driving - Hypermiling

Hypermiling

With the recent sudden increase in fuel prices, there has been an increased interest in getting better gas mileage. Several news reports have shown the value of checking tire pressures, maintaining your vehicle, and a few other items which will help to improve gas mileage somewhat.

There is a new group of people that have taken getting better gas mileage to an art form. They are called Hypermilers. Hypermiling is defined as operating your vehicle to get better than EPA rated gas mileage. The basics of hypermiling is to accelerate more slowly than usual, coast when possible, and drive at less than the posted speed limit. There are many other methods which we can discuss over the next few postings.

Go gently: The biggest load on your engine is bringing your vehicle up to speed. The weight of the vehicle will be a factor in fuel required during acceleration. Once it is at your desired speed, it actually only takes 20 to 40 horse power to maintain that speed, on level ground. The engine is overcoming internal friction, rolling resistance and air resistance. There are ways of reducing these loads, each with a small effect.

Weight: You can’t do much about the general weight of your vehicle, but checking the items you do not need to carry could. Some people even remove their spare tire, but that will depend on your situation. When I drove in the bush, I used to carry an emergency kit in my truck. Now that I have moved to a city, the likely hood of some of those items being needed is low, so they are gone. I have noticed a slight increase in gas mileage

Internal Resistance: Using the thinnest oil that will still give good engine protection is one method. Instead of 10W-30 oil, you may want to try a 5W-30. The lower viscosity will reduce the internal resistance of the engine. Be careful with this idea. You may want to check with a good mechanic on it.

Rolling Resistance: Your tires have the most effect here. Generally, the harder (higher pressure), the less the resistance. There are some trade off’s here however, and some safety concerns. A harder tire does not have the handling capabilities of a lower pressure tire. Stopping distance may be increased. Losing grip in a hard turn may happen at a lower speed. The vehicle’s ride may be rougher and noisier.
One suggestion I’ve had was that the drive tires should be inflated to a point that the side walls have lost their bulge. The thinking was that a tire performs best when the sidewalls are rigid, and the tire shape does not change when rolling. I have yet to try this.

Air Resistance: Roof racks are the biggest things here. Some vehicles have them built in, particularly mini vans and SUV’s. Some of these are actually removable, and would help to be removed. The after market racks can really destroy a vehicles air resistance. Ski racks and similar racks create turbulence, and more when being used. The trick is when you need them, use them. But realize you will pay a penalty in gas mileage. When you don’t need them, remove them, and increase your gas mileage.

These are just some general thoughts and suggestions to help improve your gas mileage. In coming posts, I will be sharing my adventures in learning about hypermiling. My vehicle? I have a 96 Chevy Lumina (please hold the snikers!). This is a heavy car by today’s standards, with a fairly big engine (3.1 liter V-6). I think it should just make it a little more challenging to test all the techniques and theories.

More importantly, I would like to hear from others who have found ways to improve gas mileage. Please send me your comments. Here are a few websites you may like to check out:

http://gasprices.mapquest.com/

http://www.gaspricewatch.com/new/default_V3.asp

http://www.hypermiling.com/