In my post on hedging gas prices, reader J.P. introduced a concept that I had never heard of before – hypermiling. Essentially, there are a group of people out there so serious about improving their fuel economy that they are swapping data and tricks in order to wring every last MPG out of their cars. Users proudly post pictures taken of their fuel economy meters. Imagine, treating high fuel economy as a competitive sport!
Although many hypermilers manage to wring out over 100 miles per gallon out of their hybrid cars, many of these concepts can be applied to non-hybrids as well. It is very intriguing to see the many different behaviors that they describe. The following are taken from this thorough article on CleanMPG.com as well as the Wikipedia entry on hypermiling.
First up, here are some of the more conventional tips that you might have read about elsewhere. Most of them follow common sense; if you make your engine work harder, it burns more gas.
- Do not use quick accelerations or brake heavily.
- Do not drive at higher speeds.
- Combine trips to reduce driving with a cold engine and on frequent short trips.
- Remove excess weight and/or cargo racks. Do not tow unless absolutely necessary.
- Minimize running mechanical and electrical accessories (e.g. air conditioning).
- Avoid driving on hilly or mountainous terrain if possible.
- Do not use 4-wheel drive if it is not needed.
In practice, this means driving very differently that you might now. You want to accelerate your emptied car as slowly as possible, and continue to drive as slowly as possible once you go past about 30 mph, especially on freeways. You want to be aware so that the second you may need to stop or can coast, you can take your foot off the gas pedal immediately. Don’t use air conditioning, do use cruise control. Track your mpg with a mileage log to measure any improvements. (Most people do not ever achieve the given EPA fuel economy ratings for their vehicle.)
Here we get into some more extreme behavior. Note that not all hypermilers engage in these activities, these are simply the ones that push the envelope. Some may be considered dangerous, or even illegal in certain areas.
- Use an real-time fuel economy meter. If you don’t have a hybrid with a built-in meter, get yourself something like the ScanGuage II.
- Inflate tires to much higher pressures. Higher tire pressures -> Lower rolling resistance -> better fuel economy. They recommend not just inflating to the psi recommended by your car, but the maximum sidewall rating allowed by your tire manufacturer. Some members even take advantage of the “factor of safety” that engineers use and pump it up to 25% over the max rating. 50+ psi is not unheard of.
- Switch to a special motor oil. Using low kinematic viscosity oil helps improve mpg.
- Forced Autostop: Turn off engine whenever possible. If you’re slowly stopping to a red light or just coasting, turn off your combustion engine completely (“force” it to “stop”). Keep the engine off while idle, and only start it up when you’re ready to go again. This reduces losses due to running the engine at idle.
- Pulse and Glide. This consists of driving using alternating periods of accelerating (“pulse”) and coasting (“glide”), and then repeating the process. It is most efficient if you turn off the engine and coast in neutral while coasting.
- Draft behind big rigs or large vehicles. Take advantage of the turbulent air behind a big rig on the freeway by driving as close as you feel comfortable behind it. The resulting lower air drag means you need less gas.
The Financial Payoff
Although many hypermilers have other motivations like less fuel-dependence, better environment, or simply competitiveness – another obvious benefit is in fuel cost savings. Reports indicate that improving your fuel economy by 30-40% is definitely possible without using all of the advanced tactics. If you went from say a combined city/highway 22 mpg based on your previous habits to 30 mpg (a 36% increase), and you drove 12,000 miles per year with gas at $3.70/gallon, this would save you $538 over a year. Worth it? Your decision.
Personally, I like learning about people who take anything to the extreme, that way I can just pick and choose what I want to implement in my own life. I think I’ll go check my tire pressure tomorrow…