View Full Version : Getting better gas mileage out of your existing vehicle

05-08-2008, 03:09 PM
Found this online and thought I'd share. The weight-saving tip is one that I can't do much about in my armored, winch-equipped, lifted 80. But the rest might be worth a try.

You can achieve similar results by following these nine commandments of hypermiling. "It's not brain science," Gerdes says.
Brake sparingly. Coast up to red lights instead of braking (though you might want to watch your rearview mirror). Timed correctly, you'll hit the green while still moving forward and expend less fuel accelerating again. A commuter should be able to pick up the timing sequence of lights along a route in three to four days, Gerdes asserts.
To idle is to sin. Cars of recent vintage have fuel-injection systems that make starting an engine more efficient than idling. So if you're going to be at a standstill for 10 seconds or more, cut off the engine. And if the drive-through line at McDonald's is a long one, park and buy your food inside.
Speed kills. "My Honda Accord, with good tire pressure and synthetic oil (see below), driven at 50 to 55 miles per hour, will get an average of 50 miles per gallon. It's EPA rated at 24/34." So just follow the speed limit, or go at a slightly slower speed. To make himself and his slower speed conspicuous to faster drivers behind, Gerdes "ridge rides," meaning he keeps his right tires on the white line that defines the far right side of the slow lane.
Avoid the big chill. Today's cars can't kick into their most efficient mode -- called "closed-loop operation" -- until the engine is sufficiently warm. There are ways to speed the process even if you don't want to invest in an engine-block heater. If you're on a round of errands, for example, always go the farthest destination first to bring up the engine temperature. If you make a series of short trips, the engine stays cold and never achieves maximum efficiency.
Beware of drag. Car racks and other automotive appendages -- even those flags honoring favorite sports teams -- reduce mpg by creating drag. The problem gets worse with speed. "Think of trying to stand up in a 75 mph hurricane," Gerdes says. So if there's something that can be taken off the car without compromising its operation or aesthetics, get rid of it. Driving with open windows is generally held to be better than using the air conditioning, but closed windows and no A/C are best.
Lose the weight. For every 30 pounds of extra weight your vehicle carries, mpg decreases by anywhere from one-tenth to one-hundredth of a percent. That may not seem like much, but mile and mile it adds up. Jettison what's not essential. If it's summer and your trunk still contains a bag of sand to help you negotiate icy, winter roads, get rid of it.
Pay attention to load. When you're driving up a hill, keep a steady load on the engine. Gerdes recommends accelerating to a target speed and then locking your foot in position so the gas pedal is held steady. That will keep gas consumption at a constant level. Maintaining a constant speed, on the other hand, requires increasing the fuel burn rate as the hill is climbed. Do that and a vehicle that registers 40 mpg on a level road can see fuel efficiency decline to as low as 15 mpg, Gerdes says.
Be not a hare. Jackrabbit starts might enable you to win the race to the next traffic light, but they're murder on fuel economy. Gerdes explains that the best mpg is had at relatively low rpm levels. It may seem like you're crawling if you try to accelerate at 1,900 rpm, he says, "but if there's nobody behind you, what's the point of going faster? You're just throwing fuel away." And if you let the other guy beat you to the next light, his presence might just cause it to change to green, enabling you to keep going without braking.
Set up for success. How a car is set up, particularly in the areas of tire pressure and engine lubrication, is critical. Gerdes recommends inflating tires to their maximum allowable pressure, a specification you'll find printed on the outside of the tire. Higher pressure means less rolling resistance, allowing you to coast a greater distance. As for synthetic oil, it breaks down more slowly than regular oil and thus promotes efficient operation of the engine for a longer period. Follow these basics and you'll get your 25% increase in mpg. You can boost it even further if you're willing to try a couple of more-involved tactics, such as avoiding left turns (and the braking that goes with them). Also, if you select parking spaces that allow you to leave by moving forward, you don't waste fuel and motion backing up.

The whole article is here (http://articles.moneycentral.msn.com/SavingandDebt/SaveonaCar/Get50MpgInYourOwnCar.aspx?page=2).

More links:

05-09-2008, 09:46 AM
I've always been told that starting your vehicle sucks up quite a bit of gas and that it's better to leave it running in between stops, is this not the case?

I need to lose the bike rack and the factory roof rack which is worthless anyway. Good read, thanks for sharing.

05-09-2008, 10:43 AM
Yeah, I always thought that there was a 2-minute rule to determine whether you should shut off your car or leave it running.

05-09-2008, 11:24 AM
Couple of supporting points and qualifiers:
I demonstrated coming back from CM07 and going out to Moab after that, that losing my roof rack moved my mileage from 15mpg or so, to 17mpg. The roof rack now adorns my garage attic.

Coming back from CM08, towing a camper, I got noticeably better mileage following the 'set a speed and hold it' approach to uphill climbs. I held 55mph going up to the tunnel, around 4300 rpm, third gear, rather than flooring it, rowing the gearbox, trying to stay at 60-65mph. Easier on the motor too.

I have in the past tried the 'lower RPM = better MPG' approach. What I found was, my mileage went DOWN. It really depends on the motor. Some motors (domestics) run great cruising around at 1900 RPM, Toy minitruck motors will too, but not as efficiently. I got noticeably better mileage hanging aroud 2500-3500 RPM. That is where the motor is made to make the best efficiency (HP/torque curves), and it works. You can use less throttle too.

Driving to CM in 'Moab Mode' (trying to imitate a bat out of h311, 80mph or so) my mileage towing the camper dropped to 11mpg. Driving in 'going back to work mode' (65mph), my mileage improved to ~13mpg. The camper had less tendency to weave too, it likes 70mph and hates 75. :eek:

05-09-2008, 11:45 AM
I kept my trip to Moab at 70MPH or less there and back. Got 17+ MPG despite the wind and passes.

Speed kills the MPG the most. OK maybe camper trailers do.

05-09-2008, 12:02 PM
I have in the past tried the 'lower RPM = better MPG' approach. What I found was, my mileage went DOWN. It really depends on the motor. Some motors (domestics) run great cruising around at 1900 RPM, Toy minitruck motors will too, but not as efficiently. I got noticeably better mileage hanging aroud 2500-3500 RPM. That is where the motor is made to make the best efficiency (HP/torque curves), and it works. You can use less throttle too.
This point is huge. People assume lower RPMs means max MPG. It is true that an engine probably uses less gas at lower RPMs, but that does not mean you are at the most efficient point (the engineering dorks measure it in lbs of fuel per HP-hour or grams per kW-hour). In general the most efficient operating speed happens around the torque peak of the engine, which is where the engine is breathing the best usually. If the engine is making enough power to move the truck at lower than torque peak RPM, then you might use less gas potentially (but not necessarily, particularly with an automatic). But if your engine is a 22R-E, then you need every single gerbil to pull their weight. It seems counterintuitive, but my mileage on 33" tires and 5.29 gears is just as good as it ever was with 4.10 gears and 28" and 30" tires. I operate my engine at around 2700 to 2900 RPM in 5th at 65~70 and get right at 20~22MPG using about 50% throttle. Like Corbet say, drop your speed and mileage goes up. In 4th gear, I'm doing about 50 MPH at 2800 RPM and I'll easily get 25 MPG tooling along at that Happy Hilux Speed.

05-09-2008, 01:06 PM
Interesting information

05-09-2008, 01:37 PM
I'll second (or 3rd or 4th) the notion that speed kills gas mileage. As part of my job I occasionally drive heavy diesel powered bricks across the country.

In my personal, non scientific but documented experience, I can move 16,000 pounds across I-80 at 85mph and 7.5mpg, or I can move the same load across the same road at 65mph and average 10.5mpg. Neither number is earthshattering, but you math majors will be quick to point out that I see a 40% increase in fuel mileage by slowing down (or, conversely, a 35% decrease by speeding up).

20mph over a 10 hour driving day equal 200 miles. A 2,000 mile drive can take 33.3 hours of driving, and cost $762 (@ $4/gallon) or it can take 23.5 hours and cost $1,066. You can save $304 by slowing down.

In all honesty, when its my 10 hours and the corporate fuel card, $300 is a small price for somebody else to pay to be home a day earlier, but when its my money, I've found myself slowing down a lot lately.

Other anecdotal evidence: Driving the Outback to Telluride with a box on the roof and the interior stuffed to the ceiling with people and stuff, going by way of GJ at 75+mph we averaged 24.5mpg.

Driving home, same load of stuff but going through Gunnison, average speed down to 55-60 we got 27.5. Telluride to Louisville on one tank, with a1/4 tank still there when we pulled into the driveway. Although the drive through Gunnison is considerably shorter it takes longer due to trucks on HWY 50 etc, but the fuel savings were undeniable.

Thats my 2 cents.

05-09-2008, 02:19 PM
I've noticed that too....with the 22RE it's sometimes better to spin it up a little bit. I love to lug it around and pretend it's a Peterbilt ;) but I think winding it up a little more in each gear is easier on the fuel.\

I'm going to get started (and maybe finish) building a Smack booster this weekend. It's an electrolysis generator that creates hydrogen and oxygen and adds it to the engine intake. I'm mainly doing it to clean the emissions. It makes ya nausious if the back window isn't rolled up all the way. The hydroxy gas mixture is supposed to make the gasoline burn much more completely and efficiently and cut way down on the HC and other compounds in the exhaust. It also usually improves fuel economy by %20 (even after the current draw of the electrolysis), makes the engine run quieter (less detonation), add a little power and reduce the soot and buildup in the engine. It's very similar to a propane injection system on a diesel rig.


I'll keep y'all posted!


05-09-2008, 02:33 PM
i'd be interested to see if that works...

we got 15.5 mpg going 80 the whole way back home from CM08, with big downshifts to make the hills, and some stints going faster. I still haven't brought myself to drive it slowly everywhere to see what it gets.. maybe the next tank....

I have found that in the mountians the big downhills offset teh fuel usage on teh ups... at least for me. which is kinda neat.

i am going to make a concerted effort to slow down though...

05-09-2008, 03:07 PM
I don't know how you can draw 20A from your charging system, generate hydrogen and oxygen, which when burned turns back into water (steam cleaning your combustion chamber?) and end up with a net gain of energy.
At the very least it is counterintuitive. I suspect you *are* starting with salt water, and recombining to distilled water, so perhaps that is the difference.
Let us know how it goes.

06-04-2008, 01:35 AM
More about hypermilers.

WAUKEGAN, Illinois (CNN) -- Wayne Gerdes is a man on a mission. He wants to end our wasteful ways, and that became plain as day to me from the moment I met him.

He is the king of "hypermilers," drivers who push cars to their miles per gallon limits and beyond. Wayne gets about 50 mpg from his Honda Accord using hypermiling techniques.

We met him at the Waukegan Regional Airport not far from his home. CNN producer Dana Garrett and I had flown there in my small, single-engine airplane, a Cirrus SR22. Within moments, Wayne and I were talking about the kind of mileage it gets.

Fortunately, as air travel goes, it is a pretty efficient mode of conveyance. Once I have leveled off at say 8,000 feet and after, I have "leaned" the fuel/air mixture to the most efficient setting. I usually get about 13 miles per gallon.

Wayne seemed to approve of this and was glad I did not arrive alone. He reminded me miles per gallon per person, or MPGPP, is really the crucial number. That led us to a conversation about the relative benefits of driving versus flying commercially.

Wayne is a nuclear engineer and the kind of guy who runs the numbers. He says for longer trips -- flying on a full airliner is more efficient than driving. Matter of fact, it is not even close.

Let's run the numbers on the latest model of the Boeing 737-900. The plane burns about 2.4 gallons per nautical mile, and a trip from New York to Los Angeles, California, is about 2,100 nautical miles. So that means it would take about 5,000 gallons of Jet-A fuel to fly coast to coast.

Now let's assume it is configured to hold about 175 people -- and the plane is full -- aren't they all these days? That comes out to 28.5 gallons per passenger. Even if the passengers were all Toyota Prius owners (which get 50 mpg), 28.5 gallons would only get them 1,400 miles down the road. So if the choice is flying -- or driving solo, the airliner wins by a huge margin.
But if you fill the Prius with people -- it becomes competitive with flying. The driving distance between New York and Los Angeles is 2,700 statute miles. That amounts to 54 gallons of gas in the fuel-sipping hybrid. With four people in the car, the Prius wins -- with an MPGPP of 13.5.

As you can plainly see, if you drive a plain old gas-engine car the airliner is more likely to be a more efficient way to travel. If your car gets, say 25 mpg, it will burn 108 gallons to get you to the "Left Coast." With four people inside, your MPGPP is 27 -- or virtually tied with thefull 737.

So if you have to be somewhere, and you don't want to waste a lot of gas and make a big carbon footprint, the airlines are probably the way to go.
Now speaking of big footprints, when I finally mustered up the courage, I confessed to Wayne that my main mode of ground transport is what he derisively calls an FSP, or "fuel-sucking pig." It's a 2000 GMC Yukon XL. (I call it the "rolling ZIP code.")

Wayne gave me some lessons in squeezing out better mileage in my FSP. Using his techniques, I was able instantly to increase my mileage by about 30 percent. But even before gas got to be $4 per gallon, I knew the Yukon was an anachronism -- and borderline immoral.

But the FSP is paid off and runs well, so until recently, economics made it smart to keep it. (We don't drive very much in Manhattan.) No question it is now time to move on to something less excessive.

In the meantime, my tires will be pumped to the max, the filters clean, the oil viscosity low and the engine will be off at stoplights.

Wayne has made me a believer.
You can find out a lot more about his techniques at www.cleanmpg.com (http://www.cleanmpg.com/).

Link to story on CNN (http://www.cnn.com/2008/TECH/06/03/btsc.hypermiling/index.html?iref=mpstoryview)

Watch a demonstration of the hypermiling techniques (http://www.cnn.com/2008/TECH/06/03/btsc.hypermiling/index.html?iref=mpstoryview#cnnSTCVideo)

06-04-2008, 07:38 AM
Some of this guys techniques are not that safe, he coasts with the engine off at times. If you have a braking system that requires electricity to run, this may be dangerous, power steering requires that the engine be running. How much more wear are you doing to the starter? how much wear are you doing to the engine by starting and stopping. Some engine require oil pressure to work on timing chains to keep adjusted. While some of these techniques are worth while, some may not be as your vehicle may require your engine running to operate vital components. I saw him on TV the other night and I was blown away with the unsafe techniques he was talking about. And the TV just let him talk about them. Just imagine a bunch of Hyper guys out there drafting behind a diesel with the engines off, and some thing happen and no power to do anything but ????? Anyhow stressful times brings out the nuts.
I do think if you are mostly in the flats, a small trailer behind the truck is going to get better Fuel ecomany than having a bunch of stuff on top.

06-04-2008, 09:07 AM
I'm scared to death of the steering wheel locking up, if I were to shut the car down while moving. I have been using "6th gear" a lot in the Subaru going down hills.. on the way to work most of the way down 285 and then most of the way between I-70 and 6th and I-70 & Ward Road. On the way home I try to coast down 470, pretty much from I-70 to Morrison road. Last tank I got 28.5, which is up about 1.5 from my last few tanks. This week's tank appears to be off to a good start as well.

Now the 80 otoh, well I drove it today and had to get gas and couldn't even fill it up, got cut off at $75.. :rant:

06-04-2008, 10:28 AM
That's how I got 19 out of the Chili.

06-04-2008, 11:14 AM
<snip> .

Now the 80 otoh, well I drove it today and had to get gas and couldn't even fill it up, got cut off at $75.. :rant:

Seems strange doesn't it Tim that they cut you off at $75? Just swipe the card a second time after returning the hose to the pump and fill 'er up the rest of the way. Stupid to have to do it this way but if you need to fill up, it can be done.