I get mail. Hundreds of pieces of mail every month, and that includes e-mail, paper mail, the occasional voice mail and even a smattering of faxes. For the last two years, an unhealthy proportion of that correspondence has been about the same thing—making your car run on water instead of gasoline. With fuel escalating to historically high prices, followed by the global collapse of virtually every market, people are inclined to search for a way to reduce their monthly expenditures for gasoline or diesel. Which, of course, is perfectly understandable.
Over the years, I've tested plenty of gadgets that purport to reduce fuel consumption. None of them worked. None. Lately, I've tinkered with a number of them that rely on the same principle: using electricity from the car's battery to electrolyze water in an onboard cell and burning the resultant hydrogen-oxygen mix in the engine. In theory, the burning hydrogen will provide extra energy, reducing the amount of gasoline you need to move on down the road. There are dozens of websites, and dozens of people on Ebay touting these devices, guaranteeing, depending on their level of chutzpah, anywhere from 15 percent to 300 percent improvement in fuel economy by simply bolting on one of their devices.
This doesn't exactly rival string theory in it's complexity. You can build a serviceable hydrogen generator from an old peanut-butter jar and some leftover copper pipe or roof flashing. There are plans to construct this device that you can get online, too. Just use some aquarium tubing to duct the hydrogen-oxygen mix (usually abbreviated as HHO) into the intake manifold, and you'll see the gas gauge stay at "Full" a bit longer—or so they say.
When these devices first hit the Net, I had an immediate opinion: Rubbish. I discussed the theoretical science a while ago. It's bad science. This malarkey boiled down to perpetual motion: something for nothing. Essentially, it takes more energy—in the form of the chemical energy in the gasoline you're burning in the engine, to spin the alternator to make the electricity and generate the HHO—than you get back. In fact, it's not even close: Multiply all the inefficiencies in that system and you only get a few percent back, certainly not in excess of 100 percent.
Two things happened after I said that. One, I got overwhelmed with mail from true believers who volunteered to have me test their car. And a lot more from people who accused me of being in the employ of the auto and petroleum companies, suppressing this breakthrough technology and keeping the American public enslaved. Sigh. Were this true, I'd be living in a much nicer house.
The second thing I noticed in the last 6 months was a change in the claims made by HHO proponents. The extra fuel economy was supposed to come not from the additional energy contained in the hydrogen, but from the hydrogen's ability to facilitate the combustion process, producing more power from the engine with the same amount of gasoline. Which is also malarkey. Before you start e-mailing me copies of those same scientific papers (I've seen them a dozen times) that supposedly prove that this works, let me tell you, these documents don't apply to your car. Without getting very detailed, these papers all deal with ultralean experimental engines with fuel-delivery systems enhanced with a stream of pure hydrogen, achieving a small improvement. They have nothing to do with retrofitting a conventional engine (with computer-controlled engine management that keeps the mixture near a perfect 14.2:1) with a device that adds a hydrogen-oxygen mix.
One point of interest: A conventional car engine ingests on the high side of 500 liters of air per minute at idle, and a great deal more at highway speed. These generators generally produce a liter or less of HHO per minute. Or roughly 50 liters per hour, of which only two-thirds is hydrogen. At atmospheric pressure, hydrogen has a density of 0.0899 g/liter. One NASA study used 640 grams of hydrogen per hour to sweeten the mixture for its conclusions. I'll leave the homework to you, but, basically, the amount of hydrogen added to the combustion process by onboard hydrogen generators is far smaller than one percent of that used by the studies that hydrogen-enrichment proponents are quoting as "proof" that their gadgets work. Could you make a hydrogen generator that made that much HHO? Sure, but it would be huge, use far more electricity than the onboard generator could possibly produce, and consume most of the power the engine put out—and it would still not improve fuel economy
I've been tinkering with a couple of homemade and commercial HHO generators. I have instrumented several cars with HHO generators I can switch on and off, flow meters, scan tools and instantaneous mileage displays. I've tested them on the road and on chassis dynamometers, and have never seen any improvement. None.
Of course, when I finally got tired of answering letters from HHO proponents and stopped posting results on our website, the buzz on the internet took a predictable turn: Commenters and letter-writers claimed that I had discovered that the things actually worked, and had stopped writing because I was embarrassed to admit my error.
More rubbish.
Here's what's really been happening. I've been working with NBC's Dateline to debunk the whole hydrogen-on-demand industry. The show's producer bought a car, an ordinary five-year old Honda Accord, to perform our tests. I checked the car over to make sure it was up to spec. Then we did some over-the-road and steady-state dynamometer testing to establish base-line fuel economy numbers. NBC followed my testing up with additional testing at an EPA-certified emissions lab, which wasn't cheap. The lab used its climate-controlled emissions dyno to establish fuel economy numbers in our Accord with the same protocols the EPA uses to generate the numbers on the window sticker of new cars. They're accurate and reproducible to well under 1 percent.
Then we took the car to a specialist who installed, for nearly $1900(!), a hydrogen generator and a system of other enhancements. There was a fuel heater, fuel-line magnets (which I debunked here), and several inscrutable boxes full of electronics designed to fool the car's computer into using less fuel. There was even a bottle of acetone to add to the fuel. (This is something that I've mentioned doesn't work here and here). The specialist guaranteed major improvements in fuel consumption. One week and nearly two grand later, the producer from NBC (who still hadn't identified himself as anyone except a guy who was tired of spending $50 to fill up his tank) picked up the car. He got a gas receipt proving the installer had seen 96 mpg, nearly triple the original economy.
We took the car straight back to that same EPA lab for another round of testing. It was followed shortly by a week's worth of road testing, dyno testing and general poking about to see what we could discover.
You can guess, right? The total improvement in fuel economy after $1800 plus of expenditure? Bupkis. Too small to measure. Nada. In fact, if you look at the EPA tests with the system switched on and then off, there's a tiny increase in fuel consumption when the system is turned on. I attribute this to the 15 amps or so of current the electrolysis cell consumes to produce hydrogen. That current uses horsepower to spin the generator, and that consumes gasoline. The hydrogen "boost" couldn't even compensate for its own losses.
And that is exactly what I've been saying for years. These systems don't work.
Thursday, July 2, 2009
Why Water Won't Improve Your MPG
How to Monitor Your Fuel Economy in Real Time on the Road
With gas hitting a national average of $4 a gallon, everyone's been talking about how to improve fuel economy—myself included, be it for taking summer road trips or avoiding goofy (and expensive) gas-saving gadgets. But how do we know if the fuel economy we're getting is accurate, whether we're driving an unmodified car—or one equipped with a supposed miracle product?
On the road, most drivers just read the trip odometer and divide by the amount of gas they purchase. Simple enough, eh? Sure is, but that doesn't account for differences in the driving cycle during each individual tankful. And that can vary an enormous amount. Of course, over a few tankfuls, the variances will average out, right? Not exactly. Your vehicle will get poorer fuel economy during the winter. That's because of the increased electrical use for lights, wipers, heat and longer warmups—not to mention the extra drag caused by moving snow and slush out of the way of the tires. Spring and fall are good, but A/C use can certainly cause a mileage hit during the hot summer months.
In the back-and-forth my weekly repair Q&A, one reader described to me his supposedly foolproof method for checking mileage—and subsequently the accuracy of his gas-saver gadget. It goes like this: He drove a delivery van on the exact same route twice a day. So he topped off the tank one morning, and drove the route like he normally does. He then installed a pretty pricey magnet (over $100) on the fuel line during his lunch hour, topped off the tank and drove the route again that afternoon. His mileage increased 12 percent, thereby proving his gadget worked. Right?
Well, even this sharp reader failed to account for the fact that in the cool morning temperatures, his fuel tank was also cooler and denser. It took a certain amount of fuel to fill the tank from the day before. And as he drove his route, the fuel heated up and expanded, largely because fuel pumps work continuously. Even then, only the excess fuel (heated up as it passes through the engine compartment) is returned to the tank. Consequently, it took a smaller amount of fuel to fill his tank. So he made the afternoon run with a warmer tank ... which he didn't refill until the next morning when the tank was cool. That cooler fuel had shrunk, making it appear that he had used less.
At my suggestion, our dear reader repeated the cycle with the magnet installed only during the afternoon runs. His results, it turned out, were very different. I had a feeling they would be.
But there's a whole lot more going on here. I'd argue that the mere expectation of increased mileage will actually make your mileage increase. I've seen it happen a thousand times: If you know the fuel economy and a gas-saving gadget are under scrutiny, you'll accelerate smoother—and probably drive a bit slower, too. I call it “voodoo mileage.” To find accurate results, a driver must remain ignorant not only to how much fuel is being consumed, but also to the entire experiment. It would have to be a true double-blind study.
Here at PM, we report fuel economy numbers on our long-term fleet by averaging the economy over a period of some months, and from a number of our staff's driving experiences. When we do a comparison test, we'll drive all of the vehicles on the same day, at the same time, at the same pace, on a several-hundred-mile loop. We even swap drivers every half-hour to equalize driving styles.
There are some tech tricks you can use to help monitor your fuel economy as you drive. I'm fooling around with a couple of devices right now. I just installed a Scangauge on my motorcycle. This $180 device plugs into the On Board Diagnostic System (OBD II) port under the dash of virtually any post-1996 car or light truck. It operates as a scan tool (much more on that here), so it gives me trouble codes and streaming data, but it also works as an electronic gauge cluster and trip computer. I can track battery voltage, coolant temp and sundry while tooling down the interstate. But one feature is invaluable: the instantaneous fuel economy readout. It gets fuel quantity data from the injection timing—the longer the injectors are open, the more fuel they squirt. It's amazingly accurate, too.
And I've just started tinkering with another gadget with some similar features: the CAMP2 from HKS. It's a scan tool/gauge package/trip computer like the Scangauge, but it uses either the car's internal dashboard display or an aftermarket TV screen of any sort. It's intended to be professionally installed, but I've made a portable enclosure that I can suction-cup to the windscreen with RAM mounts. Unlike the Scangauge, the CAMP 2 has a graphic display that can be configured to reflect a dizzying number of parameters available from the vehicle's OBD II system. Input the car's weight, and you can even get an instantaneous horsepower indication. You can look at raw numbers, or at a simple analog-style gauge with a moving needle. But my favorite is the display that gives you something looking more like an oscilloscope trace, showing you what any given engine parameter is for the last few seconds or minutes—including rewind capability, so you can review after you've pulled over to a safe place.
If you'd like to alter your driving style to achieve high fuel economy, these devices are unparalleled. The slightest upgrade, downgrade or movement of your right foot leaves a dent or a bump in the economy trace. I've only begun to investigate its potential, so stay tuned.
Don't feel like dropping hundreds of dollars for one of these high-tech gadgets? Pick up an old-fashioned vacuum gauge at the local parts store. Monitoring manifold vacuum as you drive around will give you a fairly clear picture of your instantaneous fuel economy. BMW models have had a vacuum gauge integrated into the instrument panel for generations—it's simply labeled in miles per gallon instead of inches of vacuum. Higher manifold vacuum means higher mileage—the needle will sink alarmingly as you open the throttle, which will soon teach you to featherfoot. That's good advice, because altering your driving style is probably the least expensive and most effective gas saver of all.
How to Make 4 Alternative Fuels at Home: Goodbye, Big Oil!
Ethanol
EFuel100 MicroFueler
The EFuel100 MicroFueler home-brews ethanol by fermenting a mix of table sugar and nutrient-treated yeast in the system’s 250-gal. tank. The resulting fuel, which is 99.9 percent ethanol, can either be stored in the unit or pumped into a gas tank through the 50-ft. hose. It takes 10 to 14 pounds of sugar to produce 1 gal. of ethanol, so the cost of fuel is only as cheap as the feedstock. Available in late 2008.
Production: Up to 35 gal. per week
Price: $9995
Compatibility: Flex-fuel vehicles; conventional cars if mixed with 90 percent gasoline
Biodiesel
FuelMeister II
Powered by a 120-volt outlet, the FuelMeister II mixes used vegetable oil with lye and methanol to produce biodiesel. The process takes about 7 hours from start to finish—but only 1 hour involves hands-on work, such as connecting hoses, pumping methanol and testing the final product. The fuel meets ASTM biodiesel standards and, unlike straight vegetable oil, can be burned in regular diesel engines.
Production: 40 gal. in 5 hours
Price: $2995
Compatibility: Any diesel-powered vehicle
Electricity
Envision Solar Lifeport
The modular Envision Solar Lifeport can support up to 32 polycrystalline 200-watt photovoltaic panels, which can produce up to 6.4 kilowatts of electricity. The panels are wired to an inverter, and then through your home’s electric meter. With this configuration the panels will power your home, but DIYers can mod the Lifeport into a solar-powered carport by running electricity back to an outlet in the 23 x 23–ft. structure.
Production: Up to 6.4 kw
Price: $45,199 for a 4.8-kw-rated kit
Compatibility: Plug-in hybrids and pure EVs
Hydrogen
Honda Home Hydrogen Fueling Station
A mix of natural gas, air and water is catalyzed in the Honda Home Hydrogen Fueling Station reformer, creating a gas that is 40 to 50 percent hydrogen. A membrane filters out pure hydrogen gas, which is then compressed for fuel. There’s no storage tank, so your car slow-fills from the pump at night; it takes about 6 hours to reach max capacity—171 liters at 5000 psi. The catch: Hydrogen from gas isn’t emissions-free, and Honda says consumers still have a several-year wait.
Production: 50 standard liters per minute
Price: Not yet available
Compatibility: Hydrogen cars
How to Adjust Your Car's A/C for Max Fuel Economy
Q: Years ago, a mechanical engineer told me the best way to adjust your car’s a/c for maximum fuel economy is to turn the temperature dial up and leave the fan on high. Logic says that the fan takes a lot less energy to run than the compressor, and by turning the temp up, the compressor doesn’t have to work as hard. But I’m now thinking that when you turn the temp up, hot air from the engine gets mixed in with the cold air from the a/c. So, is the compressor either on or off, or is it variable?
A: Actually, your engineer friend may be onto something. Second question first: Some cars simply clutch the compressor on and off constantly to maintain the correct refrigerant pressure and, consequently, the appropriate cooling. Others use variable displacement compressors, and still others use a throttling valve in the refrigerant line. It gets more complicated: Some vehicles, especially ones with automatic temperature controls, use air heated in the heater core to blend with cold air from the evaporator to control the temperature of the outlet air. And if that sounds like it’s inherently inefficient, it is.
Cooling your body with the fan uses a lot less fuel than cooling it with compressor-driven cold air. So, leaving the fan motor as high as possible should use less energy than running the fan slower and relying on colder air to stay comfortable. But in the big picture, I really don’t think it will make a huge difference.
Home Brewed Biodiesel Tips: Preventing Fires
There are a lot of good reasons to run your everyday diesel vehicle on homegrown oils—energy independence and less particulate pollution among them—but like all DIY projects, biodiesel production can have a dark side if it's not undertaken with the proper precautions. I've been making my own biodiesel for eight years now and have never experienced a fire, but as more people try their hands at fuel production, the news has become peppered with cautionary tales.
I am very fortunate that I live on a farm, and so my fuel operation is conducted in a stand-alone steel building, away from houses, with a concrete floor and powered vent hose attached to the mixing chamber. I also store the methanol in steel drums outside the structure, along with the finished biodiesel. Unfortunately, when it comes to making your own fuel, you can't get around working with flammable liquids and a heat source—and for most people this process is going to happen in a garage, which could be attached to a home. And so the ordinary homeowner should be extra careful when it comes to making his or her own biodiesel.
The biodiesel process starts out with some form of grease, such as new or used cooking oil or animal fats. This grease is primarily made up of triglycerides, which are glycerol molecules modified by fatty acids. In order to make biodiesel you have to add an alcohol, such as methanol, and a catalyst, such as sodium hydroxide or potassium hydroxide. The process that results, called transesterification, causes the alcohol to combine with the triglycerides, forming biodiesel and glycerin as a byproduct. Like all chemical processes, this works best when heated.
The potential hazard is introduced when you move a chemical plant into your home environment. The grease is a form of fuel (some people run their vehicles on that alone) and so is biodiesel, the finished product. Both of these fuels need to be stored outside or in fire-resistant containers. The methanol is also flammable. I store mine in the 55-gallon drum it comes in; it's steel and properly marked.
Mixing methanol and sodium hydroxide into hot grease produces combustible fumes, therefore you need to have proper ventilation. All it takes is a spark, which could come from an electrical flash from a switch, a plug pulled out of a socket, electric motor brushes, the pilot light of a water heater or an open flame, if that's what you're using to heat your grease.
Here are some other tips to follow: Before you get started, check to see if you need a permit for the storage of flammable and combustible liquids. Then, if you're hooking up an electric heating element, do not use small extension cords. Heating elements draw high current; you may even have to upgrade your electrical service. The motors used to transfer liquids from one drum or container to another should have totally enclosed housings, so that no liquid gets near them. Keep a spare bag of kitty litter around in case of a spill. And of course, make sure you have the proper types of fire extinguishers near at hand (I have three) and check with local fire, building and electrical inspectors to ensure that your proposal is safe for you, your family and the community.
Why New Diesel Engines Aren't Compatible With B100
I have been experimenting with making biodiesel for a few years now, and I am constantly watching what others in this field do as well. I monitor a forum for biodiesel users such as myself, and it's full of practical advice as well as troubleshooting for the problems that sometimes arise. Biodiesel appeals to us because it can be made from plants grown locally and burns far cleaner then ordinary diesel fuel. It results in 67 percent less unburned hydrocarbons (helping to reduce smog and ozone), 48 percent less carbon monoxide and 47 percent less particulate matter, according to an analysis of heavy-duty engines by the Environmental Protection Agency. Only nitrogen oxides, or NOX, slightly increase. It can also be blended with regular diesel in any percentage from B2 (98 percent diesel, 2 percent biodiesel) to B100, which is pure biodiesel. One of the biggest problems we biodiesel makers have experienced recently has nothing to do with the conversion process—it has to do with diesel engines.
Until two years ago, all diesel engines were B100-compatible (biodiesel cannot run in gasoline engines because it needs an engine that ignites by compression). Then standards set by both the Environment Protection Agency and California Air Resources Board, phased in for 2007, required all passenger vehicles to meet the same, stricter emissions. That meant diesel manufacturers had to reduce emissions of NOX and particulate matter to meet those of gas-powered cars. These standards were created with good intentions—to look out for our health by improving the air that we breath. (After all, particulate matter is a known carcinogen.) But the way most manufacturers did this created a setback for those of us trying to use biofuels.
To get rid of particulate matter, the diesel manufacturers came up with what's called a DPF (diesel particulate filter). But this catalytic filter becomes poisoned if sulfur dioxide is pumped through it. So as of 2007, the standard for diesel fuel was revamped as well, and fuel refineries had to reduce sulfur content to no more than 15 parts per million (now known as ultralow-sulfur diesel). The DPF is placed in the exhaust system in front of the muffler and looks like a catalytic converter used on gasoline engines. It captures particulate matter in its inner core. Periodically, the DPF has to be taken up to high temperatures to burn off the matter it has collected. This is called regeneration or postinjection regeneration. The idea is to inject fuel into the exhaust that has been vaporized, and when the fuel comes into contact with the DPF, an exothermic reaction heats it up and incinerates the plug of soot. (Squirting fuel down the exhaust? Gee, I wonder why the newer models have poorer fuel mileage.)
Biodiesel tanks
And here is where the pitfall lies for biodiesel users like myself. Most of the manufactures decided to inject fuel into the cylinders just after the cylinder fires and the exhaust valve opens. At this point, the fuel vaporizes and the vapors move down the exhaust to the DPF and clean it. Because biodiesel is denser than conventional diesel fuel (it has a longer hydrocarbon chain) and has a higher distillation temperature and boiling point, it does not vaporize as easily. Some of the fuel ends up adhering to the cylinder wall and runs past the rings, diluting engine oil.
There has been quite a bit of debate on biodiesel forums as to why manufacturers chose this method of injection. Most likely, the answer is cost. Manufacturers would rather utilize existing fuel-injection systems rather than tack on the potentially substantial cost of extra equipment. It is far cheaper to change software then it is to change hardware—just tell your electronic control unit (ECU) to apply an extra squirt of fuel. After all, they have invested a lot of money already, setting up high-pressure multiple precise injections for cleaner combustion.
Still, not all manufactures have gone this route. Some Caterpillar and Cummins engines have an injector that is placed in the exhaust pipe, not in the cylinder (in-stream fuel injection), making them biodiesel-compatible. However, these are large trucks that don't need to meet the same emissions standards as cars. Other engines clean exhaust by diesel exhaust fluid (DEF), an aqueous urea catalytic reduction called Blue Tech, otherwise known as Add Blue in Europe. This system is used on some large Dodges and some large Mercedes-Benz models. The problem with this system is you have to maintain a compartment with urea and they are mostly designed for NOX reduction.
What does this all mean for backyard biodiesel makers? Well, we can no longer brag that B100 will run in any diesel engine: VW, Mercedes, Nissan, Renault, Jeep, Ford Power Stroke, Ford E-series vans, Dodge Rams, Cummins 6.7 and Chevy Duramax will only tolerate small amounts. (For an example of what can happen if you push that limit, check out a biodiesel commercial seller who tried to run B100 in his new 2009 VW.) People in my community would like to see engine manufacturers and biodiesel makers work together to solve the B100 problem while still passing emissions standards—and selling affordable cars. In the meantime, we'll have to watch which vehicle we fill with our fuel.
Top Retro Eco-Supercars: Best Fuel Sippers of the Past 34 Years
The All-Time Stingiest: Honda Insight
It seems a bit unfair to put a hybrid in this lineup, but the 2000 Insight was the first gas-electric hybrid on the US market, and its fuel economy is just too monstrous to ignore: 49 city, 61 highway. That's better than any production vehicle before or since, and the two-seater took home the economy title seven years running. It ran on a 1.0-liter, 3-cylinder engine that made 67 horsepower (bumped up to 72 in '05-06), assisted by a 10-kilowatt (13.4 hp) electric motor-generator with a nickel-metal-hydride battery pack. Widespread use of aluminum in the body structure helped keep weight to 1847 pounds, or 40 percent lighter than a steel-bodied vehicle of comparable size. Sure it was funky-looking, but the shape gave it a ridiculously low drag coefficient of .25, also a best for any production car besides the EV-1 or the 1935 Tatra. Alas, with peak sales around 4000 per year, the Insight was retired after 2006, allowing Prius to grab the top spot. Now it's coming back in 2009 as a five seater, with mpg in the vicinity of 40/45.
Best Non-Hybrid: Chevy Sprint
The age of the fuel injector had begun decades ago, but even by the 1980s, the Sprint didn't care. With a computer-controlled carburetor, a 48-hp, three-cylinder engine and a curb weight under 1600 pounds, the Sprint achieved 44 mpg city and 53 mpg highway, and it won the fuel economy title in 1986, '87 and '88. Suzuki engineered the car, basically an American version of 1985's mpg champ, the Suzuki SA310, and many of its basics carried through to the Geo Metro of later years (see Geo Whiz). The Sprint was available as a two-door or four-door with no change in fuel economy. A turbocharged and fuel-injected version made 70 horsepower and would zoom to 60 mph in 9.4 seconds, but mileage dropped to 37/43. The base model, with a sticker price around five grand, came with AM radio; load it up and you got FM too, plus a cassette tape player and a digital clock.
One for the Truck Lovers: VW Rabbit Pickup
The iconic VW Rabbit diesel was the mileage champ for five straight years beginning with 1978, peaking at 34/40 for the 1982 model with a 4-speed manual transmission. Designed and built in the U.S., the Rabbit Pickup was what its name suggested—a Rabbit with the rear seats removed and replaced by a 6-ft. cargo bed. It had unibody construction and front-wheel drive (the only pickup sold then that had either until the Dodge Rampage arrived) and weighed just over a ton. Featuring the same 1.6-liter fuel-injected Rabbit engine making 52 hp and 72 lb.-ft. of torque, it got 32 mpg city and 35 mpg highway—tops for any truck since the EPA started keeping track. It also had an “E light" on the dash, which alerted the driver when to shift gears for optimum economy. The 1980 Izusu diesel pickup got comparable mileage, but the Rabbit gets the nod for its slightly better city numbers. But goodness knows, this was no heavy highway hauler—it certainly wouldn't compete with these 2009 full-sized pickups. Its tow rating is not available; perhaps it was never determined. But with a 1200-lb. payload, a 0-60 time of 17.8 seconds, an 85-mph top speed it wasn't what you'd choose to hook to the jail cell window for an old-fashioned prison break.
Geo Whiz: Geo Metro XFI
A couple of years ago we were calling automotive experts around the country to ask whether you could build a 100-mpg 4-passenger vehicle with today's technology. A great many experts said something like, “Sure. Take a Geo Metro, rip out everything but the seats, cover the wheel well openings and detune the engine for a top speed of 50 and you're there." We never tested that proposition, but there's no doubting the Metro's economy—the model's seven mpg titles are matched only by the Insight. The Metro XFI was especially frugal, winning five straight years beginning with the 1990 model that achieved 43 mpg city and 51 mpg highway with a 5-speed manual. Many owners reported highway economy over 60 mpg, and the 10.6-gallon tank was good for 500 or more miles between fill-ups. Like the Insight and the Sprint, the Metro featured a 1.0-liter, 3-cylinder engine. The Metro's powerplant weighed only 134.5 pounds, thanks to numerous aluminum components, and made 49 hp and 58 lb.-ft. of torque. But since the car weighed just over 1600 pounds, it had descent zip. It was reliable, affordable—base msrp was $5995—and with the rear and with the rear and passenger seats down, you could carry along a 5-ft. foosball table. Game on.
Original Champ, Still Contending: Honda Civic
This is the only vehicle on our list that you can still get with that new-car smell. The Civic has been EPA champ six times, in three different decades, beginning with the Civic CVCC in 1975, the first year the EPA kept track. Perhaps no other model in U.S. history has such a consistent record for fuel-efficiency and reliability in one package. The most economical so far was the 1986-'87 Civic coupe HF, that delivered 42 mpg city and 51 mpg highway but lost the title in those years to the Chevy Sprint. The thriftiest yearly champ was the 1989 Civic CRX HF, a two-seater that got 41 mpg city and 50 mpg highway with a 1.5-liter four-cylinder and 5-speed manual transmission. Perhaps more relevant is the economy of the four-passenger Civic sedan; since 1986 the mid-grade model has never achieved less than 24 mpg city and 29 mpg highway, and in the last decade the figures are 25 mpg city and 33 mpg hwy and better. In the late 1970s, four passengers in a CVCC meant bruised knees for those in the backseat, but highway economy was about 40 mpg. The 2008 Civic has a spacious backseat, the usual expected amenities, and an umpteen-star safety rating. Our mileage on a recent highway trip? About 40 mpg. And that wasn't even the hybrid version.
Must-Know Tricks to Max Out Your Road-Trip MPGs
The snows have melted, the trees are beginning to sprout leaves and the sun is visible in the sky for the first time in months. Yep, it’s finally springtime, and you’re looking forward to a road trip with the whole clan. Time to tune up the old family truckster ... right?
A generation ago, you could drop the car off at the corner gas station and ask for a tuneup. Times have changed. With federal regulations requiring car manufacturers to maintain like-new emissions output for 100,000 miles, a traditional tuneup has become a relic of the past. But that doesn’t mean you can ignore your car’s health. While fuel injection and ignition systems have been rendered nearly maintenance-free, it’s still necessary to change fluids and filters, check belts and hoses and generally poke around with a suspicious eye. There are quite a number of things you can do to improve fuel economy, too. And I don’t mean strapping on useless gas-saver gadgets or adding magic beans to your tank. A few simple calculations can help you optimize the amount of money you spend on fuel. So let’s hit the toolbox before we hit the road.
Check the Hoses
hoses
Radiator and heater hoses eventually fail. They’re made of rubber, and the extreme underhood temperatures combined with corrosive coolant degrade them. Avoid a breakdown on the road by checking them regularly. When the engine is cool, give all the hoses a good squeeze near the ends. A hose that’s failing develops longitudinal cracks inside, where you can’t see them. Roll the hose between your fingers and feel for cracks. Also, a hose nearing failure feels spongy somewhere along its length or shows a bulge. Five years is a good life span for a radiator hose.
Fluids and Brakes
Take 5 minutes and check the levels of all the fluids (oil, transmission, brake)—and don’t forget the battery electrolyte. Checking manual transmissions, rear axles and transfer cases might involve crawling under the car with a wrench and sticking a finger into the fill hole to feel the level of lube. Check the automatic transmission’s dipstick with the vehicle in Neutral and on level ground—after the car is thoroughly warmed up. And while you’re down there, make sure there’s a decent amount of brake lining left on your pads.
Filters
It’s usually pretty easy to check the air filter without any tools. If it is visibly dirty, it’ll need to be replaced, not just blown off with compressed air. Consider a cleanable, reusable K&N filter instead of buying disposable paper filters. Clean out dirt, leaves and dead bugs from the filter housing, too. Replace the fuel and oil filters as recommended in the owner’s manual.
Coolant
coolant
A proper mix, winter or summer, is 50/50 undiluted coolant to water. Increasing the concentration of coolant to water in the system raises the boiling point and lowers the freezing point. But, contrary to popular belief, extra glycol in the coolant won’t provide more protection in the winter, and could actually make your engine run hotter in the summer. Be sure to visually inspect the radiator filler neck and header tank for murky corrosion and contamination. Check the concentration with an inexpensive hydrometer when the engine is cold.
Cleanup in Aisle Three
leaves
Remove leaves, road debris, bugs, roadkill and mud from the cowl intake and the radiator. Disintegrating leaves can work their way into the heater core, causing poor heater or a/c performance, not to mention a musty smell. Dirty or clogged radiators can cause overheating.
Tire Pressures
tire pressures
Low tire pressures waste gas and make your tires wear out prematurely, not to mention making your car hard to control. If the outside air temp has changed with the seasons, your tires might be under- or over-inflated today. Tires can lose 1 to 2 psi for every 10-degree temperature drop. Tire-pressure monitoring systems (TPMS) are standard on all 2008 and newer vehicles. But don’t blindly rely on these devices. And don’t just wait until the light comes on. If your car uses the ABS system to calculate tire pressure by checking how many revolutions your tires make over the road, any single tire could be 20 percent (5 to 7 psi) low before the system trips and turns on the light. That’s dangerously low.
If you have a TPMS with pressure transducers in the wheels that gives you a readout of the individual tire pressures on the instrument panel, you still shouldn’t just wait for the light to tattle. It’s easy to check from the driver’s seat, so why not do it every day?
No TPMS? Tire gauges differ, especially the ones built into the pump at the corner gas station, so use the same gauge consistently. Buy a $10 tire gauge and keep it handy. Don’t forget to check the spare, too. Check pressures when the tires are cold, first thing in the morning. The recommended tire pressures are printed on a sticker somewhere on the driver’s side door, the doorsill or in the glovebox. Staying near the high end of the recommended pressure range improves fuel economy and tire wear and helps compensate for any extra weight you tote around on family road trips.
Gadget-Free Gas Saving
gas gadgets
The summer road trip is still a part of our culture. True, gasoline ain’t getting any cheaper—but neither is air travel. Plus, have you dealt with the TSA lately? A good road trip might be more appealing now than ever before. Here are a few steps you can take to minimize the fuel bill.
> Start by shedding extra weight. Ditch the golf clubs, that bag of rock salt, the old battery you never got around to taking to the recycling center and any other junk in the trunk.
> Likewise, remove the luggage or bicycle rack that lives on the roof even when there’s no luggage or bicycle aboard. That additional aerodynamic drag at freeway speeds can reduce economy substantially.
> Be sure you’re using the correct viscosity and grade of oil. A thinner, lower-viscosity oil requires less power to pump around the engine. Auto manufacturers have re-engineered cars to run on lower-viscosity oil to save fuel.
> Oil that is rated Energy Conserving has been tested to provide a further gain in economy.
> If you’re not seeing the kind of mileage you’d like, it might be time to check the engine’s performance. Buy or borrow a scan tool and learn what all those trouble codes and engine parameters mean. You may be able to eke some ponies out of the old bus, too. A new air filter or other minor tweak might increase mileage and performance measurably.
> Finally, remember that the biggest variable when it comes to consumption is you, and the behavior of your right foot. I know, you’ve heard that mantra a thousand times before. But driving moderately and anticipating traffic (so you can lift off the gas early instead of braking) will make the largest difference in your mileage.
What's the Right Gas for My Car?
Do the math and figure out definitively which pump delivers the most miles per dollar.
It says right on the gas cap of your car: “91 Octane Only.” Some cars specify the lower-grade fuel, but your ride needs premium. Which is, of course, more expensive.
Your car may require a higher octane rating because it has a higher compression ratio, or forced induc-tion from a turbo or supercharger. As the piston travels up in the compression stroke, the space for the air and fuel becomes smaller and temperatures increase in the combustion chamber. This can cause low-octane fuel to ignite spontaneously, before the spark plug fires. The result: very high pressures, called knock or ping. Because the pressure spikes before the piston has reached top dead center, it pushes down too soon, resulting in poor engine efficiency. Prolonged knock can actually damage the pistons. High-octane fuels are more resistant to knock.
Car manufacturers protect modern engines with knock sensors. When knock starts, the engine computer enriches the air/fuel mixture to prevent damage. If you burn a lower grade of fuel than your car requires and the engine has a knock sensor, fuel economy and performance will simply drop off with no harm to your engine. The question is, do the lowered performance and fuel economy balance out the reduced cost? Here’s how to decide. (Remember: This is only appropriate if your car has a knock sensor and won’t be damaged by lower-grade fuel.) Fill up with the fuel that has the recommended octane rating (let’s assume it’s 91) and drive for a few tankfuls. Check your fuel economy by dividing the miles driven by the amount of fuel consumed.
Now try a midgrade fuel and repeat. Make sure the driving route, traffic and weather conditions are similar. If the fuel economy is just about the same, try the next lower grade. Repeat until you see a drop-off in mpg. When you do, go back up one grade (to the one that didn’t lower economy) for the best mileage.
Now, instead of dividing by the gallons consumed, divide by the cost of each tankful. This will give you the miles per dollar. If you are still saving money, reserve that better gas for times when you really need performance—like for towing. On the other hand, you might find that the cheap stuff is actually more expensive per mile of road than something with higher octane.
Quick Fuel Efficiency Tips to Beat the Gas Crunch
Three or four days after buying my first car, I came to a disturbing revelation: Paying for your own gasoline is expensive! You don't realize just how much of a pain in the butt it can be—and how much junk advice is out there on the Web—until the entire financial burden rests solely on your shoulders. So I decided to geek out, learning everything I could about how to squeeze more miles per gallon into every fill-up—and share it with the rest of the pump-fearing masses.
Over the past couple years, I've tried every gimmick—acetone, fuel-line magnets, intake air swirlers, you name it—to top out on gas mileage with my 1991 Honda CRX. Needless to say, these gimmicks didn't get me anywhere—as Popular Mechanics' own Mike Allen has proved so many times, and he's debunking them once again. So I jumped on the fuel-economy bandwagon with the next generation of Mike Allens. Some call us hypermilers, but at my MPG forum and blog, we go by ecomodder—someone who combines car tweaks, behind-the-wheel techniques and some basic skills to cut back on trips to the gas station.
My new lifestyle has taken me from an average (but very unsatisfying) 30 mpg to an efficient 55 mpg in the last year, and the 70 mpg mark is looming on the horizon. With gas prices hovering around $4/gallon and forecasts scouting even worse news, getting even more out of every gallon of go juice has become even more important to me—and you can get in on the action, too.
Being a bit of a tech- and gear-head, some of my mods (such as converting my automatic transmission to manual, with my lean burning Japanese-market Civic VX engine just arriving in the mail for a transplant) might seem a bit extreme. Still, while I've beaten the 27-mpg EPA rating on my CRX by over 30 percent with the best practices below, there's so reason you can't go out and cut at least 10 percent before a summer road-trip weekend. These simple tricks will definitely help you save fuel—without ripping your car apart.
1. Track Your Mileage in Real Time
Knowing what your consumption looks like from tank-to-tank is important, but that's really not enough. Knowing what mileage you're getting in real time—being able to compare it to what you got yesterday or even 10 minutes ago—is the new way to drive these days.
Luckily, ecomodding combines the love of saving money and adding gadgets to my car. People with cars made after 1995 have it relatively easy: All you need to do is throw some money at a fuel-economy computer like the Scangauge, and you're instantly instrumented. For older cars, you may need to get your knuckles dirty by installing a vacuum gauge, which measures how hard the engine is working, or explore the growing world of DIY fuel-economy electronics, like the arduino-based MPGuino. Either way, a conscious mind combined with instant feedback should get you that instant 10 percent.
2. Only Brake When You Have to
I recently found myself fighting against a 20-mile backup passing through Hartford, Conn. The traffic wasn't exactly stop-and-go, but the pack was constantly speeding up and abruptly slowing down. So I did something a little different.
When everyone started taking off, I gave myself a 10- or 15-second buffer before hitting the gas and accelerating. By accelerating slowly and leaving space ahead, I could see the brake lights ahead before I expended a significant amount of gas, coasting right back up to the car in front of me. If I timed it just right, my Honda would meet the car just as it started up again, without using the brakes at all. My gas mileage actually went up to over 70 mpg while sitting in traffic!
3. Always Stay Alert on the Road
To drive without brakes or coast toward stops effectively, you have to know what's going on around you and be able to anticipate how traffic will play out. That means paying attention to the lights on your daily commute—heck, memorizing them—and trying to anticipate whether they will, say, turn green by the time you get there. And, again, always look several cars ahead to see if the brake lights are starting to come on in anticipation of a coast.
4. Drive Like You're on a Bike
OK, don't necessarily go 20 mpg out there, but try to imagine biking over the same route that you're driving on: When you're headed uphill, it takes a lot more effort to maintain speed than it does going down, so give the car a break and let yourself lose a few mph on the way up. Relax, you'll easily get it back on the other side. Your car burns the most gas when it's forced into high-load situations, so try to remember what makes biking difficult (like going really fast, accelerating really hard and speeding up hills), and make those situations as painless as possible by laying off the gas.
5. Make Your Car Your Own
Every mainstream passenger car is a compromise built with many different drivers in mind. Because there are all too few vehicles built specifically with gas mileage as the primary design element, there's a lot of improvement to be had in modifying your existing ride. Some people will do little things to improve aerodynamics, like adding a grill block, smooth wheel covers or rear-wheel skirts. Others will remove alternators, swap engines or convert their car to run all-electric. Either way, optimizing the design of your car is one of the most effective ways to improve fuel economy. After all, it was my automatic-to-manual conversion that really boosted me from the high 30s and low 40s to that 55-mpg territory.
6. Pump Up Your Tires—Really
One of the biggest areas in which manufacturers compromise fuel economy for comfort is in tire pressure. That 32-psi rating is mainly there to make the ride smooth as silk, even as you run over potholes and pedestrians. It can be controversial, but believe it: To get the best mileage out of your car, up the pressure to the maximum listed on the sidewall. The ride will get a bit rougher, but your rolling resistance will be reduced and you'll get better gas mileage. But don't just do it once and forget about it! Make sure to check your tire pressure every other time you fill up, or you could be leaking air and losing MPGs.
7. Use the Right Ride for the Job
It may seem like a no-brainer, but it may be the ultimate fuel-saver: Why take a gas-guzzling SUV to work when a smaller, more efficient fuel-sipper will do? And if public transportation or carpooling is an option, you'll not only save on gas, but also wear-and-tear on your vehicle.
8. Multi-Task With Your Daily Routine
Are you going out to run weekly errands, or are you just dropping one letter off at the post office and coming right home? You will essentially cut distance traveled and fuel usage in half by making all your stops at once, instead of taking lots of short roundtrips.
9. Plan Your Route Ahead of Time
Take the path of least resistance. That's one with fewer stoplights, not as much traffic and, yes, lower speed limits. Even if you save 0.1 gallons of gas each day, you'll save more than $130 per year.
10. Avoid Rush Hour at All Costs
These days, many offices are offering flexible hours, so errands can be run at any time. Try to avoid being stuck in traffic if all you have to do is leave 30 minutes earlier or come in 30 minutes later. And, yeah, set those alarms and take off for the beach early this summer. With those prices at the pump, you deserve it.
