There are two major categories in fuel savings:
- driving habits
- vehicle maintenance/upgrades
First, DRIVING HABITS:
Anticipate, use your brakes less, and don’t accelerate quickly. Look far down the road ahead, even if “far” is a city block. Get into turn-lanes smoothly and early: avoid accelerating to get in front of traffic. Anticipate stops or slow-downs ahead and take your foot off the gas : try to coast much more than you brake. Additional coasting distance saves fuel and extends brake-pad life.
Remember: he who leaves stoplight quickest pays more at pump.
Use Cruise Control. It saves fuel and speeding tickets. But it’s not just for cruising. The “Resume” button can give you decent acceleration without wasting fuel.
Overdrive and gear selection. If your automatic has Overdrive, use it. If you have a manual transmission, shift early to keep engine rpm’s lower and always use the highest gear for highway cruising.
Slow down. As you increase speed above 60 mph, wind resistance increases rapidly as a percentage of total fuel consumption. Typically, every mile over 60 mph costs you ~1% in fuel economy.
Carefully consider your route and the time of day: traffic flow is a huge factor.
For example, say that along your interstate travel route, the space between vehicles averages 3 to 4 car lengths… typical of traffic in many large cities. If it’s stop-and-go, fuel economy will be bad. But if traffic is moving smoothly and fast (at 60 – 80 mph), then fuel economy can be superb: those rushing vehicles create a jet-stream of air that dramatically reduces wind-drag losses. Up to 30% gains are possible. For maximum fuel economy, follow a larger vehicle and use cruise control. Also keep in mind wind direction: if the wind blows strongly from the right and you’re in the right lane, you’ll get NO break in wind resistance from vehicles ahead.
Plan and Combine errands to make fewer trips. Think like your great-grandparents did. Plan meals and grocery shop once a week to once a month: just make a list of other errands during the week, plan your route, and do it all in the same trip. Arrange with other parents to carpool or pick up the kids for you.
Such planning may seem like work at first, but it frees up time, helps you relax, and can improve your average fuel economy by 5 to 15%. It can also cut your average weekly miles by 20% or more. Total dollar potential: save 10-35% of monthly fuel costs.
How does this help fuel economy? During the first several miles while warming up, the engine and transmission are not operating efficiently. This is why city fuel economy can drop dramatically in cold weather, when it can take 10 miles for the engine and transmission to warm up. Automatic transmissions in particular can be power hogs when fluid is cold, and manual transmissions can feel like you’re shifting in molasses. (Hot/cold temperatures are one of many reasons to use a full-synthetic 100,000-mile transmission fluid).
So, combining two or three trips into one reduces the miles you drive, and also gets you better fuel economy.
Use air conditioning wisely:
– Keep your windows rolled up at speeds over 40 mph: the air turbulence around the window makes the air-conditioning cheaper than the fuel-economy penalty from additional wind-drag.
– Turn off the air and roll down windows at speeds under 40 mph in the summer heat: the additional wind-drag is cheaper than the air-conditioning.
Fuel economy impact? ~ 1-5%.
Buy fuel wisely. Ok, this isn’t actually improving your fuel economy, but here are some tips to save fuel money. Tuesday afternoon or Wednesday morning fill-ups will normally save you money: those are typically the lowest prices of the week. Also, filling up in the morning when the fuel is cooler will get you a few extra cents of fuel. So your best time to fill up is — on average — Wednesday morning. Don’t “top off” your tank: you risk losing fuel to the station’s vapor-recovery system, giving them back some fuel you’re buying.
Use a good fuel additive at fillup. Injectors with excessive deposits have poor spray patterns that can cost you 2 to 15% in fuel economy. Those deposits are caused by poor quality fuel. Since ’95 the EPA has required all gasoline to have deposit-control additives. But about half of all gasoline on the market is lowest additive concentration (LAC) gasoline, which barely meets the regulation and contributes to excessive deposits.
What can you do? First, if your vehicle is designed for premium gas , and you’re using it, your injectors may be fine: most premium fuels include higher additive levels that are effective at keeping injectors clean. However, what if you don’t use premium? Use “Top Tier” detergent gas — if you can find it — because this new fuel classification meets the 2004 GM/Honda/Toyota/BMW deposit control standard.
If you don’t need premium and Top Tier isn’t available, you probably need an additive. BEWARE: there are many mousey fuel additive products that generate nice sales profits but do little for your vehicle. Find a good one that will actually clean your injectors, keep them clean, and (for diesels) lubricate your fuel pump. Our website suggests fuel additives that we know do the job with quality, for a fair price.
Lose some weight! Clean out your vehicle’s trunk (and maybe the back seat). Tools from that weekend project two months ago is costing you fuel! Every 200 pounds in your trunk costs you roughly 1 mpg.
Don’t drive! Carpool, occasionally ride a bicycle or walk, telecommute for part of your work-week, or take public transportation.
Shift your work-hours to avoid gridlock. Stop-and-go traffic is hard on fuel economy. Arrange traveling to/from work when traffic flow is running smoothly at the speed limit.
Minimize idling — idle smart: Engines only need 10 seconds for warm-up before driving (30 seconds if below zero). Idling your engine more than a minute typically costs more fuel than re-starting it. So avoid drive-through lines at banks and fast-food shops: instead of sitting in line, park and go inside. BUT, when you must idle with an automatic transmission, put the transmission in Neutral or Park while you’re waiting: this will cut fuel usage at idle by 10-40% depending on the vehicle and the transmission temperature. (With manual transmissions, use the brake to keep from rolling back – not the clutch. That saves fuel and extends clutch life.)
Park in the Shade: The hotter the fuel tank gets, the more gas you lose to evaporation.
Smart vacation thinking: If your vehicle is a gas guzzler, consider renting an economical vehicle to drive on vacation. With a discounted week-long rate at better fuel economy, the rental might pay for itself. If you lease your vehicle, using a rental vehicle will also lower your total lease miles.
Keep a log of your mileage and fuel. By monitoring your fuel economy and driving habits, you can see the cost impact of changing your driving style, and you can spot the poor fuel economy that is often a first-alert to maintenance issues. In addition, as you make changes to improve fuel economy, you can measure the exact results (averaged over five or more fill-ups for best accuracy).
Second: vehicle MAINTENANCE & UPGRADES.
These areas often get skipped in recommendations on getting better fuel economy. That’s unfortunate because they can have huge impacts.
Most fuel economy improvements fall into two general categories:
- decrease friction in the vehicle’s drivetrain (engine, transmission, differential, wheel bearings, tires);
- make it easier for air to flow through the engine, anywhere from the air intake to the exhaust tailpipe.
These are the same areas that performance-enthusiasts change to get more horsepower. I spoke with a Lexus mechanic who has won awards for his modified 2003 Dodge 2500 pickup with the Cummins turbo-diesel engine. He was surprised that with his many thousands of dollars in horsepower upgrades, he was getting about 23 mpg even with large tires and higher ground-clearance. “Every time I increased the power, the fuel economy improved.” No surprise to me: except for tires and suspension, he increased his truck’s efficiency with every power upgrade.
Keep your engine tuned up. If you have a dashboard service-engine light on, you’re likely wasting fuel. Example: bad Oxygen Sensors are a classic problem that can cost you 5-15% in fuel economy. Overall, poor engine tuning and lack of maintenance can decrease fuel economy by 10-20%, or more.
Inflate your tires to their optimum: HIGHER pressures than “normal”. Read carefully. You need EVEN road-contact pressure (equal across the tread) to maximize everything: tire life, fuel economy, bad weather traction, and best overall handling and cornering characteristics with increased road safety. Probably over 85% of car tires on the road are under-inflated, and this costs money in fuel and shorter tire life. Under-inflated tires can lower gas mileage by 0.4 percent for every 1 psi drop in pressure of all four tires.
“Experts” generally (wrongly) define the “proper” pressure as the vehicle manufacturer’s recommendation. That’s what the government says. That’s what most service shops follow. Unfortunately, that’s seldom correct in your and my vehicle tires.
Fact is that OEM wheel/tire combinations for most passenger cars and light trucks are designed by the TIRE manufacturer for even tread pressure on the ground when inflated to between 35 and 42 psi [pounds per square inch]: that optimum inflation range is much higher than the recommended 28 to 33 psi that are in many owner’s manuals or on door-jamb labels.
If your tires normally wear the tread off the shoulder before the center of the tread, then your tires ARE under-inflated.
So how much air pressure should you use? Visit our full online Ultimate Fuel Economy Guide for important details.
Impact? By our conservative estimates, most vehicles are riding on tires that are 8 psi low, costing about 3% in fuel economy.
Watch your tire choice. Replacing your tires/wheels with wider and/or taller ones may look awesome, but keep in mind that your choice could have a 1 to 3% penalty in fuel economy… or even more in extreme cases like “monster truck” tires/wheels.
Switch to best-quality synthetic oils and filters throughout your drivetrain: engine oil, transmission fluid, differential gear oil and wheel bearing grease. This advice — to use the best synthetic lubricants — is rarely heard, yet it’s an easy area to save money. You save in routine maintenance costs, long-term maintenance costs, time-in-the-shop, and of course in fuel economy. But unfortunately it’s not a simple area to understand. So here’s a brief primer on synthetic lubricants:
The number of vehicle owners turning to synthetic engine oil has increased dramatically, because consumers are learning that synthetics are better than petroleum products in every way, BY DESIGN. More vehicle owners are beginning to realize what the OEM’s and quick-lubes don’t want them to know: that full synthetics can cut wear rates in half and outperform traditional oil for up to 35,000 miles between oil changes.
But consumers don’t realize THREE KEY THINGS:
First, that the benefits of synthetics extend to every lubrication area in the vehicle. For example, most transmissions fail because their transmission fluid has failed, either because the fluid hasn’t been changed frequently enough, or because the fluid overheated. Synthetic fluid helps hugely to prevent transmission problems, and naturally saves fuel at the same time.
Real life: My ’94 Taurus SHO got 10% better fuel economy with engine oil and transmission fluid change, my ’02 Sierra 2500HD Duramax truck got 8% better fuel economy with just synthetic engine and differential fluids, an acquaintance picked up over 20% on a 37 foot gas-engine motor-home, and my friend Phillip’s 1999 Olds Silhouette van picked up 20% just by changing to synthetic engine oil — saving him over $600/yr in fuel.
In other words, for most vehicles, high-performance synthetic lubricants are one of the simplest and best changes that you can make to improve fuel economy — yet it’s rarely mentioned! One reason is because it’s brand dependent. Most people will get 2 to 12% improvements in fuel economy, IF they use one particular brand of lubricants, but less or no improvement with other “synthetics”.
Second, not all “synthetics” are real PAO synthetics. Today, in fact, most are fakes because the lubrication industry has agreed that it’s OK to deceive you. (Our site explains how to tell a true synthetic from a petroleum “synthetic”.)
Why do you need real PAO synthetics, anyway? Because in every way they perform better than petroleum products — by design — and because they are uniquely able to save you the maximum amount of money with 25,000 and even 35,000 mile drain intervals, while other “synthetics” are designed for 7,000 to 10,000 mile use, to maximize petroleum-oil-company profits out of YOUR pocket.
Third, not all real synthetics are the same. As a Mechanical Engineer who has worked for years in automotive, and done extensive research (see About Us on my site), I live in the everyday world of real results and have developed some strong recommendations based on data and verification with personal testing. In fuel economy, for example, ASTM standardized fleet testing results with one company’s synthetic lubes in commercial vehicles shows an average 8.2% improvement in fuel economy vs the common big-name commercial lubricants. (See this data on our site.)
Few companies will show legally-binding data based on standardized (tightly defined) test parameters like this, because independent testing on their products will not produce favorable data to support their product claims. In comparison, hundreds of ASTM 4-ball Wear Test results in independent laboratories over years have shown that one company’s lubricants are consistently designed to reduce frictional wear and internal fluid-friction losses to a greater extent than even most synthetic lubricants. Friction reduction translates directly to better fuel economy and much longer-lasting vehicles.
You want data from respected independent testing laboratories? Ahh — so you know marketing claims are worthless! We have overall comparative testing data for many specific oil blends, including Mobil 1: ASTM testing by independent laboratories. While all the oil companies run these tests, generally only one company publishes significant data, while the others rely on vague performance claims and clever marketing slogans. Beware: test results against generic “competitor A, B, C” are legally meaningless. But published/advertised test data against named products is legally binding, with huge lawsuit potential from competitors.
Improve airflow AROUND your vehicle:
– Loaded roof racks or cargo pods can cut 5% or more off your fuel economy. A cargo rack that slides into a trailer hitch allows you to carry extra stuff, still get into your trunk, and use less fuel.
– Sunroof air-deflectors can be handy, but do cost you a bit of fuel. Removing the air deflector might save 1/4 to 3/4% in fuel economy.
– Consider adding a truck bed cover, either soft-type or hard-shell, to get a 1 to 2 mpg boost. What about dropping your tailgate to travel, or replacing the stock tailgate with an “air gate” net or louvered tailgate? They’re not as reliable: results depend on vehicle aerodynamics, bed length, and what you do (or don’t) have in the truck bed.
– Reduce air turbulence under your vehicle: “Off-road” packages with protective underbody “skid plates”, or “ground effects” styling packages can add 1-4% in fuel economy. The downside? The vehicle may be more difficult to service.
– Adding an air deflector to the roof of your truck/SUV when towing will also add 1 to 3 mpg by reducing trailer wind-drag. But it can also reduce your non-towing fuel economy by about the same amount if it’s still in position on the vehicle when you’re NOT towing.
Improve airflow into the engine. This can happen in several stages of increasing complexity, but the first place is the air filter, where air enters your engine. If your filter is dirty, that reduces fuel economy — up to 10% in the worst cases. However, there’s a conflicting problem. Conventional filters should NOT be replaced before the OEM’s recommended interval or they will increase your engine wear rate: they rely on the “dust cake” buildup to achieve effective filtration, which unfortunately causes a pressure drop that reduces fuel economy.
Easy Improvement: Replace your air filter with nanofiber filters born from military/aerospace technology. (Just released in 2005 with worldwide patents, and reasonably priced.) You get pressure drop nearly as low as an oiled gauze filter while filtering out 100% of wear particles down to 3 microns (for real). Clean with an annual tap/shake/vacuum. No warranty problems.
Intermediate: The next thing to look at is the air-filter box design. Many OEM’s have a restrictive flow-path going into the air-box (to reduce engine air-intake noise, or to reduce water intake if you drive through a foot or two of water), including lots of internal stiffener ribs. Sure, the improved strength from ribs may enable you to stand or kneel on the air-box, but they often cause pressure-drop and turbulence.
There are two improvement routes: an aftermarket air-induction system, or DIY modifications.
The best route is to look at replacing the entire air-intake box and filter with an aftermarket “air induction” or “air intake” kit.
Caution: oiled gauze filters won’t keep out many wear particles, so they produce high engine wear-rates. Plus, excess “tack oil” can cause reduced fuel economy and trouble with warranty coverage at many dealers. Choose wisely — go for the OEM certified nanofiber solution if one is available for your vehicle, because nanofiber air filters are the best technical and economical compromise between no filter at all and a restrictive stock filter. The minimum intake choice should include a two-stage dual-density oiled-foam filter: far better than oiled-gauze. If you can’t get at least that in an aftermarket air induction system, then we recommend skipping it: upgrade to a nanofiber air filter, and consider modifying the stock air-box as we outline on our website.
Advanced: see our site for these details.
Our easy, intermediate-level and advanced airflow improvement suggestions can realistically net you from 2% up to a maximum 8% improvement in fuel economy.
Improve airflow out of the engine: Install an aftermarket exhaust system. These have larger diameter pipes and larger, less restrictive mufflers. My point isn’t to get louder, but to reduce “backpressure” losses which cut down on horsepower, torque and fuel-economy. Since increased noise is typical, and some systems are intentionally designed to be loud, you may want to shop for the exhaust sounds you do or don’t want.
Upgrade to a more fuel-efficient vehicle. Careful. Companies and sales people want to make money on your vehicle switch, so watch out for your best interests. First, price matters. You have to save a lot of fuel to pay for a big difference in vehicle price. Paying hybrid premiums to get more fuel economy probably won’t begin to pay you back before you sell the vehicle. Second, real-world driving shows many hybrids don’t live up to their mpg hype. (See our surprising comparison in the online detailed version of this, between hybrids and turbo-diesel vehicles.)
Finally, be cautious in your search for improved fuel economy: don’t waste money on fake fuel-economy improvements. Many products are total fakes or hugely exaggerated. Most companies tiptoe around those realities, but I don’t. So here’s the truth:
– Most “oil additive” or engine “metal treatment” products are or will be embroiled in lawsuits in a number of states. If an oil additive claims a fuel economy improvement over 1%, forget it. Lubrication Engineers explain that oil is a highly engineered chemical package, and that if you want better performance you must buy better oil. Base your choice on published, standardized ASTM test results. That’s the best and cheapest way to get better lubrication performance.
– Fuel treatments/additives and catalysts? 2-15% gains are available, with the biggest improvements for vehicles with a long diet of cheap LAC (Lowest Additive Concentration) fuel. Question the cost vs value. The answer is Yes to some good ones, No to some poor ones, and “why bother” to a lot of them. Question who to trust, and research what you buy.
– A mechanical or electronic aftermarket product? Fundamentally, if it isn’t actually improving airflow through the engine/exhaust, it’s probably NOT going to boost fuel economy. Our site has specific “improvement” examples that WON’T save fuel.