How to Maximize Your Prius Fuel Economy - By Rick Kearney

If you own a Toyota Prius, one of the most important issues on your mind is most likely, “Why am I getting less miles per gallon than the car is rated for?”

The answer is actually quite complex. The solution is not.

The first point to remember is that the EPA mileage estimates are derived using pure gasoline. Consumer gasoline (that which is available on the open market for general use) contains up to 10% Ethanol. You can do nothing about this. EPA estimates are also done on a test track, not in “real world” driving situations. They do not take into account traffic, trains, weather, other drivers or the countless other factors we encounter in daily life.

Here are some tips to help maximize fuel economy. They are geared primarily for the Prius, but most work just as well on other cars.

Tip #1. Inflate your tires. Low tire pressure causes increased resistance and wastes fuel. Low tire pressure also causes excessive edge wear on your tires, shortening their life.

This sticker is located on the driver’s door opening. Note the recommended pressure is 35 front and 33 rear. This is the MINIMUM pressure that should be in your tires. On the sidewall of the tire is another number, 44 psi. This is the MAXIMUM pressure that should be in your tire. A tire with less pressure rides softer and uses more fuel. A tire with more pressure rides slightly harder and uses less fuel. Set your tires at 40 psi and watch your mileage increase!

Tip #2 Air Conditioning. Prius air conditioning uses electricity to turn the compressor, while conventional cars use a belt on the engine. When the compressor is running, it uses power. Power that comes from gasoline. Automatic air conditioning means the ECU (the computer) can turn the compressor off when less cooling is needed. Set your A/C to a level you find comfortable. 76 degrees is comfortable for most people. “Lo” temp setting runs the compressor much more and uses more power. Remember, everything that uses electricity uses more gasoline. The power has to come from somewhere! The gasoline engine supplies the electricity for everything on both Hybrids and Conventional cars. Headlights, radios, blower fans, all want their share of power.

Tip #3 Slow Down and Smell the Roses. Excessive speed uses more gasoline than anything else. “Jackrabbit” starts and hard acceleration combined with hard braking wastes fuel. Prius is designed to get the best economy in the city. Slow, easy acceleration means the car needs less electricity to get up to speed and therefore less gasoline. Coasting allows the gasoline engine to turn off and not use any fuel at all! Sitting at traffic lights, the gasoline engine will also shut off and save fuel. Driving at steady speeds between 30 and 40 mph allow Prius to opportunity to make use of the electric motors and not use the gasoline engine for additional power.

Tip #4 Avoid little trips. Some people tend to drive only 1-2 miles to the store then the car sits for an hour or more. Then they drive 1-2 miles home again and again the car sits. These trips do not allow the gasoline engine to be run to operating temperature. Therefore, the engine is never shut off during the travel times! Plan your trips to make them in one big circle. Make the best use of Prius’ capabilities.

Tip #5 Lighten the Load. The more weight you carry in the car, the more gasoline needed to move it down the road. Do you really need those golf clubs every day? What about that bag of clothes you will take to the Goodwill someday soon? Every little bit helps.

Tip #6 Oil Changes. Dirt doesn’t weigh very much. Dirty oil, however, weighs more than you think. Old oil has collected dirt from your engine and holds most of the small particles in suspension. Changing your oil can improve your fuel economy. Regular maintenance is important.

Try these tips and track your fuel mileage the proper way. Fill your tank and record the mileage on the odometer. Drive until empty then refill and record the mileage again. Calculate how many miles driven divided by the number of gallons of gasoline pumped. That is your proper mileage. Get 6-8 readings and find the average. Remember to always stop pumping fuel when the pump clicks off. Do not top it up. Be consistent.
And always remember to drive safely!

-Rick Kearney is one of three Toyota Certified Master Diagnostic Technicians at Earl Stewart Toyota and the dealerships Resident Hybrid Genius. Rick travels with Earl regularly on the Lecture Circuit dispensing advice and answering questions for Florida consumers about their vehicles. Rick is now in the process of training Palm Becah County first responders about hybrid vehicles so they may safely conduct their rescue operations.