Driving for Mileage

It seems we’re all obsessed with fuel efficiency and find ourselves confronted with a choice to either purchase (at considerable expense) a go-cart style eco-mobile and risk life and limb in a collision with a squirrel, or learn to drive our present vehicles for the best mileage possible.  If you’ve half a brain – and you likely do because you’re reading this – you’ll choose the latter.

     To begin, we start with absolute basics: tires and wheels.  Insure that your tires are in good shape and that they are properly inflated.  During the 2008 presidential campaign, candidate Obama suggested that by simply inflating our tires we could effectively equal the impact of drilling for our own off-shore oil.  This is absolute nonsense, of course, but as far as it goes, it’s still good advice and may render a small percent increase in your mileage if you’re currently driving on nearly flat tires.

     Most modern vehicles have tire inflation indicators so if your vehicle is so equipped and the warning light isn’t on, you’re good to go.  If not, stop at your local gas station and check your pressure.  While there, check your tires for unusual wear.  Worn outer or inner treads may indicate poor wheel alignment which will cost you more in gas and tires as your vehicle literally drags and grinds your tires from place to place.  Get it checked.

     Engine tuning: Modern vehicles have largely negated the need to “tune” your engine on anything resembling a regular basis.  Old style steel-electrode sparkplugs eroded quickly and had to be reset or changed seasonally lest you be visited by a smoke-belching, sputtering, gas-guzzling – or dead - engine.  However, today’s platinum-electrode sparkplugs wear slowly and modern electronic ignitions compensate for upwards of 100,000 miles wear.  So, if your engine isn’t misfiring you’re probably OK.  Nevertheless, have your sparkplugs checked at around 50,000 miles even if they aren’t causing problems because they could be slowly rusting to your engine block which could cause them to shatter during replacement.  This would require your engine to be literally disassembled to remove the remains and that’s a very expensive proposition!  Have them checked at 50,000 miles!

Oil changes: It’s important that they’re done on time as old oil breaks down, losing its ability to lubricate and causing your engine’s metal parts wear prematurely.  Very bad!  You also need to insist on the manufacturer’s recommended viscosity.  Heavier oil (i.e. 10W-40) sounds like it will protect better than a 5W-20 weight but that’s not necessarily the case.  Thicker oil also makes your engine work harder and less efficiently as it labors to turn its internal parts, burning gas – your gas - to compensate.  Don’t go cheap here.  Get the good stuff at the recommended viscosity and it’ll pay dividends.  And now the hard part – driving.

Driving and Acceleration: Younger drivers generally have a hard time with this but you must practice driving like an old man if you want to save gas:  Accelerate slowly and safely.  Glide – Glide! - to your desired speed (65-70 mph – any faster and all bets are off) and then let the cruise control meter your engine speed.  Caution: Try not to “glide” out in front of an at-speed eighteen-wheeler lest you become bumper-splatter on your way to Duluth.  Use your head and pick your merge points carefully.  Consistency here will put dollars in your pocket. I’m driving a 2005 Saturn Vue with a 3.5 liter, 250hp, front-wheel drive V-6 and get upwards of 28-30 mpg highway and 18-22 mpg city, depending on weather, wind, and geography, and you can do the same.  Four-wheel drive is another matter.  A four-wheel drive transmission’s extended gearing is a constant drag on your engine for which you will pay a percentage reduction in fuel economy.  Don’t buy it if you don’t need it, and don’t expect miracles in a blizzard.

Acceleration: (Pay attention!) Knock off the jack-rabbit starts and stops and the pedal-to-the-metal acceleration from lane to lane just to get ahead of the jerk that just darted ahead of you.  Highway driving is a marathon not a sprint.  Drive accordingly and you and your gas bill will benefit significantly.  Each time you stomp the accelerator and hear that “throaty, European growl,” know that your engine’s eating a hole in your wallet.   So stomp away if you like, it’s your money!

Rationale: The reason moderating your acceleration pays such big dividends relates to the Kinetic energy equation, Ek = ½ MassVelocity2, which basically dictates that moving twice as fast requires four times the energy (22); three times requires nine (32) and so on.  This also applies to stopping which explains why reckless drivers frequently splatter themselves on bridge abutments or into the back of slow moving eighteen-wheelers.  Slow down, save gas, and live to drive tomorrow.

Air conditioning, fast food drive-thrus, and the lunatic fringe: Unless you own a high-end vehicle in which the air conditioner senses cabin temperature and cycles the air conditioner, your air conditioner is a mileage liability when engaged.  Of course, if you own a high-end vehicle, you likely don’t give a damn about driving for mileage and shouldn’t be wasting your time with this.  (Note: I envy you and want to be you someday.)  For the rest of us, you can try this if so inclined:

Cycle the air conditioner: When you become uncomfortable, set the air conditioner to maximum and turn it on long enough to cool the cabin and then cycle it off.  Repeat as necessary and you’ll realize another small savings in fuel efficiency.  Whether it’s worth it or not is up to you.  Then too, if you’re really anal and accustomed to camping out on the lunatic fringe or find yourself on a Quixotic quest to save the planet, you can wait until you’re traveling down hill before turning the air conditioner on, taking full advantage of gravity pulling the vehicle.  The savings in requisite horsepower may now be used to cool the passenger compartment while still maintaining good fuel economy.

Drive-thrus:  Don’t use drive-thrus when stopping for a burger.  Instead, pull in, park, and shut the engine off.  Stretching your legs will help stay you alert and you can more easily confirm your order - always a good thing.  You may also take the opportunity to recycle whatever it was you consumed at the last stop, leaving yourself physically relieved and blissful in the knowledge that you’re saving the planet by not idly wasting fuel in the drive-thru.

So, in ascending order, driving for mileage can be summed up thus: Inflate and align your tires, tune and maintain your engine, use cruise-control driving methods, and, most importantly, moderate your acceleration and idling time.  Follow these suggestions and there will be money in your pocket and gas in your tank at journey’s end.