Improving Gas Mileage

In my last blog, I discussed getting your vehicle ready for a road trip. Today I would like to pass on to you some tips on improving gas mileage. You will find as you read this installment that there are similar and overlapping recommendations between vehicle maintenance and getting your best gas mileage. If you’ve been watching the trend at the gas pumps, the prices are on the way up once again.

Let’s face it, some people just don’t care about gas mileage and some just can’t be bothered with it. Hey, in New Jersey, a very popular vehicle is the Chevy Suburban. These are among the largest SUV (Sport Utility Vehicles) available usually outfitted with large displacement V-8 motors. Those that “swear we need this huge truck” often have large families. If you wish to get your 4 children and 2 dogs around, you need this vehicle. Thinking about having the gang all together takes precedence over whether the vehicle gets good gas mileage or not.

It seems good gas mileage is a “state of mind” type of deal. My Jeep SRT-8 gets about 12 mpg around town. If I get on occasion say 12.5 mpg, then I am all proud of myself! Some folks use 15 mpg as their acceptable level yet others expect nearly 25 mpg and higher. Just a a little side story first…it has relevance, trust me! Not long ago, I was able to get 31 mpg out of my 2006 Corvette Z06. “But Uncle Vinny, that’s a beast of a V-8 motor and an absolute rocket, what gives?” This  feat was accomplished on the highway, windows closed, A/C off, alone in the car, traveling at a cruise control set 55 mph and transmission in 6th gear(top gear). This sentence contains almost all of the secrets to getting the best gas mileage out of your vehicle. So let’s really get started!

Remember when I said that a well maintained vehicle is a safe one? Well it turns out it’s also a gas efficient one, too. A properly kept vehicle is usually operating at its peak performance levels. Fresh motor oil has the best friction reduction properties. Make sure that you are using the proper grade of oil called for by your vehicle’s manufacturer. Using a thicker grade of 10W40 over a recommended 5W30 will cost you mpg. There is less internal stresses, less power loss in an engine circulating a lower viscosity oil. Even though some may argue that a 10W40 may provide better protection, it will cost fuel savings and after all that is our discussion. Some have suggested a waste of 1-2% fuel efficiency when using a 40 weight oil instead of a 30 weight oil. Also keep in mind that if your car is under warranty, and you decide to use a non recommended viscosity, the manufacturer can void the warranty. If the vehicle is not running a synthetic oil, a switch to one may prove worthy in a 2%  improvement in fuel mileage. Oils touted as being most fuel efficient are often 0W30 and 0W20 oils. By the way, you will not get a great improvement in mpg by making any one change, it’s an additive effect. Each modification to the vehicle or driving habit adds a little toward maxing out each gallon of fuel.

A clean air filter is another good maintenance item. An air filter’s job is to trap dirt and debris and prevents them from being ingested by the vehicle’s motor. Most modern cars are equipped with computers that adjust air/fuel mixtures in response to dirty, more restrictive air filters. Trapped dirt leads to more restriction and less air entering the intake and motor. More restriction and less air means less power. A clean filter may improve acceleration by as much as 5 to 10 percent. On older carburated vehicles, a clogged filter will definitely affect gas mileage. This is a set up found usually on pre-1980 vehicles. So for most of you, think of this as a good maintenance item that provides more power and more power is ALWAYS better! If you take the filter out and cannot see diffuse light through it, then replace it. While you are there, tap the filter to free dust/dirt and leaves off. Reach into the airbox and make sure it too is free of dirt and debris. Please remember, an Uncle Vinny personal safety note, always wear protective glasses/goggles when ever you work on a vehicle.

When was the last time you fed your vehicle a good quality fuel system cleaner?  These cleaners added to the fuel tank will often treat 15 to 20 gallons of fuel.  Dirty intake valves and the number of miles poorly spraying fuel injectors waste fuel.  The best time to add these is just before filling the tank with fuel.  Do it right at the station.  Usually a helpful attendant will gladly add it prior to filling up the tank.  Most experts agree that the fuel cleaner is best added just BEFORE your planned oil change.  Loosened debris and some of the residual chemicals from the cleaner do enter the oil and “dilute” it.  Another quick tip,  run the treated take to 1/4 full before refilling.  This will maximize the time treating the engine.  Follow the label directions on the bottle especially in regards to repeat use( some say okay for each fill up, others every 3 to 6000 miles!!!!).  We’ll have a future blog on fuel system maintenance.  In the mean time a few good brands, and ones that I have personally used, are RedLine SI-1, GumOut Regane,  Amsoil P.I. and Chevron Techron.

Another item recently discussed was tire pressure. Under inflated tires waste gas, are unsafe and hurts performance. Usually a 3 psi ( pound per square inch) of under inflation for a vehicle’s tires costs 1% loss in mpg. I recently checked a friend’s tire pressures and the tires were down nearly 9 psi. That’s a 3% loss in fuel economy. If you are in the market for new tires, and gas mileage is important to you, then look for some of the newly touted higher fuel mileage tire designs. These tires have tread patterns conducive to decreasing rolling resistance and tire compounds that help to roll better as well. Wide, chunky tread tires with sticky tire compounds are not the best for gas mileage. They may be good for other things, which we will likely talk about in a future blog.

Remember my rant from a previous blog about folks just driving way too fast. Well slow down and save gas. The “double nickel” or 55 mph speed limit implemented in 1974 was designed primarily for fuel mileage (secondarily we saw a 15.3%  decrease highway deaths!). Gas mileage on some vehicles can be improved by 25% if you travel 55 mph verses 75 mph. Another way to see this difference is a fuel rating of 20 mpg at 55 mph compared to a fuel mileage of 15 mpg at 75 mph. Comparing the two in dollars and cents, you will have 50 extra miles to drive before using 10 gallons of gas at 55 mph. That’s a savings of 3.3 gallons (15 mpg) or about $9.50( $2.85  gallon of premium gas).   But wait there’s more!  I have seen my share of aggressive drivers who gun the car off the line, slam on the brakes and punch the” go pedal” to the floor once again. They make a gazillion lane changes while performing their best NASCAR moves and all for what? To get a few cars ahead of you? This is not only a safety issue but also wastes fuel. This behavior puts a lot of extra wear and tear on all the involved vehicle systems. Extra throttle, extra brake use, extra strain on the suspension components and additional tire wear all occur during this event…let alone increasing the chances for driver error.

Jack rabbit starts, heavy unnecessary accelerator use wastes gas (yes I know it’s fun getting pushed back into the seat, the rush of power). A nice steady increase up to cruising speed is best for gas mileage. Most automatic transmissions will go into overdrive mode and this higher gear often allows for lower rpms and for higher gas mileage. If you have a manual transmission, you can select the highest gear as soon as you are at cruising speed. If the vehicle is equipped with a cruise control type device use it on the highway. This device will help with gas mileage as it will attempt to keep the vehicle at a constant speed.

When traveling at highway speeds, it’s best to do so with the windows up and the A/C ( air conditioner)off.  Now don’t do this on a hot day folks. If you need the A/C, set it at its lowest setting that is comfortable for you. With a lower setting (72 degrees) the compressor will run at a minimum. The compressor is a belt driven item and sucks power from the engine. When more power is needed, the engine works harder and hence uses more fuel. At around town speeds, use the windows. Keeping the windows up at higher speeds increases fuel efficiency by decreasing the car’s wind resistance. The more aerodynamic a vehicle is, the less power it needs to push itself through the air. A vehicle needs less power to drive the A/C at higher speeds than the power needed to overcome the drag of open windows (think of the air trapped in the car traveling at a higher speed, to the way a parachute slows a person falling to Earth).  Speaking of aerodynamic drag,  if you are not using that roof top carrier, take it off.  It has been shown that the “hamburger box” style can ruin your gas mileage by as much as 5%.

When traveling, attempt to make as few stops as possible and combine trip destinations. Visit a shopping center and park in a location that will allow you to walk (yes that’s something we can all do for better gas mileage and health) to the cleaners to drop off laundry, then to the next door bank and finally to the supermarket before returning to the car. Fill up on gas before you go home so that a special trip to refuel isn’t necessary. If you are waiting in line or just waiting for someone to come out and meet you, shut off the car.  Idling wastes gas!  Remember you are not traveling any where, an idling vehicle gets ZERO miles per gallon.  I use the 5 minute rule.  If you are going to be sitting and idling for 5 or more minutes, shut ‘er down!

And speaking of extra cargo, clean out your trunk of extra junk…uh, that’s the car’s trunk! I have been shocked by what family members tend to keep in their hatch and trunk areas. Are they awaiting a surprise visit from Monty Hall and hoping to win a prize if they have a (fill in the blank)? I recently found in my sister’s hatch area a snowbrush (uh, it’s July), a heavy drill, books, gloves, empty boxes, etc., etc. all adding to the weight of the vehicle. In fact, she made me laugh when she asked me onetime if I “did anything to the car because it seemed to be quicker off the line”. No, I just took out about 50 pounds of stuff. For each 100 pounds of excess weight, it can cost you 2% in fuel economy.  Remember, every little effort to save fuel adds up, a little here and a little there.  Think of it the same way that loose pocket change adds up in that piggy bank.

So do you remember when I said in the beginning of this blog that the short story about my Corvette Z06 had almost all the answers to getting good gas mileage? No, it isn’t about the fire-breathing 427 under the hood. It’s about a light weight, aero-dynamically shaped, well maintained vehicle using synthetic 5w30 motor oil with an engine churning in 6th gear at a cruise control set to 55 mph, windows closed and the A/C off!  Hey my buddy’s Honda sedan can’t get 31 mpg numbers on the highway. He also can’t get the dash computer to read single digit mpg readings when he mashes his right foot into the accelerator pedal…snicker, snicker.

I will begin a series of blogs on exterior car maintenance beginning with car washing techniques and eventually moving into other car detailing areas.  I appreciate all of your comments and compliments!  Hey, tell a friend about this blog!

Thanks for stoppin by!

Stay safe out there!

Uncle Vinny