Driving with fuel economy in mind can help you conserve fuel and save money. Here are some steps you can take to ease up on your fuel consumption.
Ease Up on the Accelerator
Accelerate no more forcefully than needed to mesh smoothly into traffic. Racing up to cruising speed may make you feel like Jeff Gordon, but it'll quickly drain your wallet.
Fuel consumption is directly related to how hard the engine is working. Ask it to race away from a stop rather than accelerate sensibly, and you'll be visiting the gas station all too frequently. Guaranteed. Ask it to barge up a steep grade rather than feathering the throttle just enough to sustain momentum, and you'll watch the needle on your gas gauge move too quickly toward "E."
Even jabbing the accelerator during passing maneuvers or lane changes eats away at fuel economy. On the highway, zooming up to the traffic ahead, then having to hit your brakes, is a fuel-wasting exercise and a sure sign of an impatient driver. The best drivers are smooth and efficient in every move they make.
Lose Traction, Lose Fuel
Even if you're not trying to race away from a stop, you may find your tires slipping, especially on wet or gravel surfaces. Each time a tire slips, whatever the cause, you're losing gas mileage as well as endangering yourself. Take care when starting off on slippery or unpaved roads. Slow down on rough pavement.
Consider RPM and MPG
An engine's workload is determined by how fast the crankshaft is turning. The crankshaft transmits engine power to the transmission and then to the wheels, and crankshaft speed is measured in revolutions per minute, as indicated on a tachometer.
A manual transmission gives the driver full control over rpm because the driver can make the engine speed up or slow down via gear selection. The lower the gear, the higher the rpm. The higher the rpm, the more torque the engine is producing, and the more fuel it is using. Automatic transmissions take some of this control out of the driver's hands, but they, too, can be manipulated to maximize fuel efficiency.
With a manual gearbox, shift into the upper gears quickly. Optimal shift points vary, depending on the engine/gearing combination, but for best economy you might need to shift to second by about 15 mph, and reach top gear by the time you're traveling 30 to 35 mph.
Rule of thumb: If the engine is revving faster than necessary to sustain an even road speed, move to the next higher gear. Downshifting follows a similar standard. If the gas pedal has to stay close to the floor to maintain speed, you probably belong in the next lower gear. "Lugging" in too high a gear isn't good for the engine or your finances.
Take Advantage of the Upshift Light
If your manual-transmission car has an upshift indicator, use it as a guide. Using signals from the engine, transmission, and accelerator pedal, the indicator tells you exactly when to upshift to maintain greatest efficiency, and thus top economy.
When the engine speed is high compared to the position of the accelerator pedal, the shift indicator lamp signals that you can get the same performance with less fuel by shifting up without losing power.
Tests conducted by Saab and the EPA compared operation of cars that had an upshift indicator to those that did not. In the EPA city-driving test, use of the indicator yielded an average gas mileage improvement of more than 9 percent. Even without such an indicator, you should shift into a higher gear sooner than you normally would and use fifth gear as much as possible to stretch your fuel.
Watch the Tachometer
Because tachometers are no longer limited to performance models, more drivers than ever have a chance to pay attention to engine speed as well as road speed. This allows you to find the engine's most efficient rpm and stay close to that point whenever feasible. What speed is that?
The exact figure depends on the engine but is typically the speed at which it produces the greatest torque output. For economy's sake, it's generally wise to remain below 3,000 rpm most of the time and to shift into the next gear before the engine gets much beyond its optimum rpm level. Too low an engine speed does nothing for your finances, so running below 1,500 isn't ordinarily a good idea.
Skip an Occasional Gear
No rule says you have to use each gear of your manual transmission every time, going through a never-changing 1-2-3-4-5 sequence. Try going directly from first to third (skipping second); or go from second to fourth without using third. This technique is especially useful if heavy traffic has caused you to rev too high in the lower gear already, as when merging onto an expressway from the entry lane.
Get the Most from Your Automatic Transmission
An automatic transmission liberates you from shifting gears yourself, but nothing is free, and an engine must work a little harder and use a bit more gas to transmit power through an automatic transmission than a manual. For proof, look no further than EPA fuel economy estimates, which are invariably lower for an automatic transmission than for that same vehicle equipped with a manual transmission. Still, there are some things you can do to maximize fuel efficiency in an automatic-transmission vehicle.
During acceleration, listen as the engine note rises and then falls to get a sense of when the transmission is reaching the "top" of one gear ratio and changing down to the next lower ratio. Also, watch the needle on the tachometer climb up the rpm range and descend correspondingly. Remember, the higher the rpm, the more fuel you're burning.
Some automatic transmissions tend to stay in lower gears a little too long for peak economy. You can sometimes coax the transmission into shifting to high gear earlier than usual by letting up on the gas as you pass 30 mph or so. Then, once it's in top gear, continue to accelerate very gradually.
Watch That Little OD Light
Virtually all manual and automatic transmissions have an overdrive gear that can be employed to save fuel. It's usually the highest-numbered gear (or gears), and it lets the engine run at a slower speed (or lower rpm) while the car maintains the same road speed.
If you're looking to save gas, get into an overdrive gear as soon as possible and stay there until you need the extra power afforded by a lower gear.
With an automatic transmission, a lot of that decision making is out of your hands. Automatics tend to move to the highest gear on their own, precisely to save fuel; at cruising speeds, overdrive (OD) kicks in. But you can shift into and out of OD. On newer cars, it's usually done via a button on the shift lever. Typically, an "OD" light illuminates in the instrument panel when an automatic is shifted out of OD. If you have inadvertently shifted out of OD, press the button to get back in for optimal fuel economy.
Many modern automatic transmissions allow drivers to change gears manually by moving the shift lever through a separate gate. This doesn't duplicate the degree of gear control afforded by a manual transmission, but it will allow you to select a lower gear for more throttle response. Doing so increases engine rpm and burns more gas. For best fuel efficiency, shift into the highest gear whenever possible or simply shift into Drive and let the automatic do what it's designed to: Select the most economical gear at each step of the way.
Make Sure Nothing's Afoot
Don't drive with a foot resting on the brake pedal, however lightly. Even the slightest application of the brakes while moving will drag down fuel economy. It'll place an unnecessary burden on the engine and transmission. You'll wear out your brakes rapidly, as well.
Even when your car isn't moving, you should be thinking about ways to save gas. In our final section, we'll take a look at some ways to conserve fuel while your car is standing still.