EPA Fuel Economy Myth: Too High, Too Low?

ThosLives asks: "I have seen here on Slashdot , and just about every other publication, numerous articles about fuel cells, hybrid vehicles, and the inaccuracies of EPA fuel economy stickers. For instance, today there is a review of the Toyota Prius that had the famous line 'Since no car really achieves the EPA estimated mileage...' I happen to drive a car with an EPA sticker of 21 city 25 highway (all figures in miles per gallon). I've driven the car for 47000 miles and the lowest I've ever seen is 23 and some change; the highest, 36.3 (I'm probably about 60% highway 40% stop-and-go and yes, the high was on a long highway trip). My all-time average is about 28.5. As most people get less than the EPA mileage, how does the Slashdot readership fare when it comes to EPA sticker vs actual experience, and on what type of vehicle?"

"Am I a rare breed that can drive my car (2.0L I4, 170 HP, 6-speed manual) aggressively (I've had coworkers and friends say 'woah!' more than I'd like to admit *grin*) and still stomp the EPA sticker? Did I get lucky with a phenomenal car? Am I enough of a counter-example to thwart the belief that the EPA figures are 'too liberal'? Are fuel economy issues just FUD from [insert lobby group of choice]? Or is the answer simply 'it depends on how you drive, what you had for breakfast, and the color of your neighbors' cat?'"

Thus the phrase...

Your mileage may vary.

Re:Thus the phrase...

and everyone's mileage DOES vary.

I own a 2004 Prius, and I must say that I DON'T get the mileage advertised, although I have seen per-trip variations outside what I so-far consider my normal range. My own figures are closer to 47MPG (combined) for the life of the car, now at 4000 miles. However, my style of driving tends to be shorter trips taken in a hilly locale--both of which negatively influence mileage. Slightly longer trips (a daily commute of 60+ miles) and flatter terrain (coming north to town on the coastal plain) allows a friend here (also with an '04 Prius) to average 53 or so. All other factors seem similar--we have similar driving styles, same tires at same pressure, etc.--but there's a big difference in the mileage figures for the same car. I don't think the EPA takes this into account; they're looking at a bad extrapolation of data based on emissions and a short test--almost a perfect, no-wind, flat-land drive.

I believe the Prius is a good, capable machine. I can see how, in the right circumstances, the car would do as well as, or better than, the EPA figures. Lots of folks do it.

Check out Greenhybrid.com [greenhybrid.com] and Prius Chat [priuschat.com] and see what others have to say.

Re:Thus the phrase...

Yes, this is obvious since it's the whole point of a hybrid like the prius. It takes less energy to drive slow (like in city driving). And you loose your energy in city driving from all the stop and go and idling at stops. A prius doesn't waste power idling, and gains the power back when braking. So it will get better mileage city, thats the whole idea. Hybrids don't do well on highway driving do to energy losses. For driving down the highway a conventional drivetrain is best. When it comes to high mileage on mildhybrids like the insight it's because it's light and areodynamic, not because it's a hybrid.

Re:Thus the phrase...

There's an interesting statistic on hybridcars.com about how making minimal improvements on gas milage can vastly affect our foreign oil dependency. The jist of it is that if we could improve the average gas milage of the US by one mile per gallon, we wouldn't have to drill in the arctic reserve. If we improced average gas milage by 8 miles per gallon, we wouldn't need to import oil from the middle east at all. So even though we may not be getting sticker values for milage on hybrids, they still kick ass compared to most sedans and such, and espically SUV's and the Hummer with its 8 miles per gallon. Bottom line, even though you aren't getting super phenomenal milage, you're still getting awesome milage, which is good in a variety of ways.

http://www.hybridcars.com/oil.html [hybridcars.com]

Re:Thus the phrase...

I will tell you like I tell everyone else:

I wish gas prices were lower, but if prices were $5 a gallon, it would not affect my driving habits. I know lots of people who complain about gas prices, gas mileage, etc. but the majority of the complainers I know make more than $100k a year and still drive cars that get less than 20mpg. I finally showed the boss the math, and he quit bitching about it.

A vivid example: 50 miles per day at 20mpg = 2.5 gallons per day x 20 days a month (1000 miles typical) = 50 gallons per month. The price difference of $1.50 and $2.00 comes to $25 per month. For someone making $100k a year, this difference represents a grand total of .00406 of their BRING HOME income. (less than 1/2 of 1%). This is trivial. * Even someone making 1/3 of that amount, $33,000 would see a 1% increase (lower taxes), which is almost trivial. And its still cheaper than buying a new car that gets better mileage, by a long shot.

Most of the users on slashdot spend more than this on porn. ;) If $325 a year is going to make or break you, you need a better job, NOT a better car.

*(Based on income of $100k, tax of $20,000, [typical] 52 weeks / 4 = 13 cycles x $25 per cycle = $325 yearly / $80,000 bring home = 0.0040625)

Re:Thus the phrase...

Have you ever noticed that when they widen a road, the traffic doesn't tend to get lighter?

On the same note, if you make cars that get 50 mpg and are affordable (less than 20k) then yes, more people would buy them, and drive them instead of using public transport, since it would be a price advantage to drive your own. Not counting the fact that your own car is more convenient, etc. This would mean even more traffic because it would be cheaper, more pollution because many individual cars make more smog than one bus/train, and more traffic problems, PLUS we would have to build yet MORE roads to support all the new econo-boxes, all in a vicious cycle brought upon us by the people who are demanding high mileage cars.

My solution is everyone buy a new truck that gets 13mpg avg. like my new Chevy 2500HD. This way we won't be tempted to drive so much, and be forced to suffer all the problems that good gas mileage brings. ;)

Re:Thus the phrase...

True, every little bit matters... ...but my bicycle gets 20 miles to the burrito. My round-trip commute to work takes 1.2 burritos. And believe me, if I wasn't commuting via bicycle to work, I'd be consuming the fuel anyways.

Re:Thus the phrase...

Presumably your bicycle has a gas turbine?

If that's a bean burrito, I'm guessing the rider has one instead...

Re:Thus the phrase...

...my bicycle gets 20 miles to the burrito. My round-trip commute to work takes 1.2 burritos.

Great, first the Middle East, now Mexico.

Re:Thus the phrase...

Current: Ford F150 5.4L V8, I average 19mpg with a heavy focus on highway driving and light emphasis on difficult offroad or towing duties (live in a very rural area). It does OK and beats the sticker mpg mpg by 2. Towing heavy loads in the 5000-7000lb range, mpg drops to roughly 10mpg which is bad. My next truck will have to be a diesel. Ironically, my car in highschool and college was a 1.8L Diesel VW Rabbit with extended fuel tank. It averaged 60mpg and with the extra fuel tank I could fill it up at the start of summer and not need to refill to school started in the fall. Fuel economy has been solved way back in the day, sadly no one in the US wants diesels.

Diesel? Depends on your goals.

You have to consider motivation, too.

Yes, turbo diesel cars get incredible mileage, but the particulate emissions -- despite dramatic improvements over the past decade -- still fall near the bottom of the heap.

So, if you want to improve your mileage to save a couple of hundred dollars a year and/or to reduce dependance on foreign oil, a diesel is definitely the car for you.

On the other hand, if you're concerned about that grey haze hanging low in the sky that you notice every morning driving to work and wonder about what [commondreams.org] it's [californialung.org] doing [airinfonow.org] to [healthandenergy.com] your [ec.gc.ca] lungs [bbc.co.uk], you might want to consider other technologies.

Re:Thus the phrase...

My buddy is an off-roader, and I go with him occasionally. I've seen the H2 in action, and trust me, it can't get out of it's way. I've seen one basket ball player, and one foot ball player, each driving his own H2, on two seperate occasions.

We had to winch both of them out with his K5 blazer (which is now painted on the side "H2 RESCUE TEAM".)

The H2 has the same transmission as many many many [gm.com] chevy vehicles, geared identically. How come they don't get 10MPG? The H2 is designed to be a gas guzzling, curb sitting POS, so people with more money than sense can look down on the commoners.

Re:Thus the phrase...

and espically SUV's and the Hummer with its 8 miles per gallon.

Which is extremely scary. I have a Class C motorhome with an engine that make's the hummer's look like a economy-car engine. It's a Ford 460 gasoline engine with a Holly 4bbl big-bore carb on the top of it. I pull a 30 foot camper body that is over 10 feet tall and have 2 extra tires hitting the pavement. and I get BETTER gas mileage than the hummer.

There is something really wrong where a vehicle that is 4 times the size and more than twice the engine AND using older non fuel injected fuel technology that is significantly less efficient than the new and supposedly high-tech Hummer.

What are they doing so wrong on the hummer?

Re:Thus the phrase...

Essentially, nothing. The problem is that people are buying the hummer and other SUVs as car-replacements. That means not only are they getting around in them on a day-to-day basis, but they are also driving them like they drove their cars: fast, hard, and with overdue maintenance. Larger, less efficient vehicles become even more inefficient (not to mention dangerous) when driven hard. Since the hummer is considered to be something of an off-road vehicle, it probably doesn't lose huge points on efficiency in that area. However, since most people are not using the hummer for its claimed intended purpose, it is grossly inefficient, but not shockingly more so than other, similar vehicles. I have a friend who drives a Durango as if it was a sports car and he gets about 8-10 MPG. Basically, a big part of the whole gas consumption problem is not just the vehicles but also how they are driven. We are going to need large, gas-hog engines for the foreseeable future to drive trucks and heavy equipment, but when those engines are overused in personal vehicles, those vehicles need to be thought of as trucks instead of as cars.

Re:Thus the phrase...

Get off it.

Speed limits were designed way back when you could reduce your gas intake by slipstreaming off your buddy (the guy in front of you). Same idea as geese flying in formation (reduces drag).

Nowadays, speed limits serve a different purpose: adding money to the state's coffers (in the name of education, social security, etc.). A friend of mine works with the cops (state & local), and yes, they do have quotas. Twice a month, cops are everywhere, then they disappear for a few weeks.

I do not condone doing 90MPH+ in a population center (i.e. center city Philly), but once you're out on the highway or the backroads, let loose. If your car has the speed and breaking distance, you have nothing to fear.

As an aside, under all circumstances, I obey the yellow speed signs (speed limits or otherwise). They actually serve a purpose (if a sign says 15 MPH, you bet that I'm going to abide by it).

I'd like to see the cops chase after those who impede traffic (30MPH in a 45MPH zone). Course, we can't have that in PA, as it would offend all those older voters (I think they outnumber everyone else). Grannies, wearing coke-bottle glasses, out driving their Buicks. Left-blinker, for 2 1/2 freaking miles.

Re:Thus the phrase...

I'd like to see the cops chase after those who impede traffic (30MPH in a 45MPH zone). Course, we can't have that in PA, as it would offend all those older voters (I think they outnumber everyone else). Grannies, wearing coke-bottle glasses, out driving their Buicks. Left-blinker, for 2 1/2 freaking miles.

I'm convinced that it's not the grannies, but the Buicks. Every one I've encountered has driven below the speed limit and comes to a complete stop at every turn, even merging into highway traffic. I will never buy a Buick because they seem so incredibly hard to drive.

Signed,
A fellow Pennsylvanian.

Re:Thus the phrase...

Everyones mileage will vary. This is for one very good reason. The mileage of your car is determined on a chassis dynometer running the federal driving cycles for city and highway. The current cycle is the LA77 I belive. That would be a cycle designed in 1977 as if you were driving around in Los Angeles California. So every car is based of a very set driving. Obviously no one will ever drive just like this. Some peoples driving will get poor mileage some great just on their routes they drive.

The other factor is indeed how you drive. I drive very agressively, but at the same time I get good mileage. Why is this? Well largly because I have worked on projects getting getting highmileage for years, Futuretruck. I understand what the car is doing and what to do to run it where I can get the best mileage. And often if your driving right, you will get good mileage, since making the most of your car and its potential is a very similar thing to how to get good mileage, conserving energy and so forth. Its not how powerful your car is, it's how you drive. A professional driver can roast a fool even when driving much less of a car then the fool.

Also driving a POS car with no power for years got me good at making the most with little power, so now I don't need to use it all to do what people do with more power. People are often shocked with how my car performs when with me driving, and they have the same car.

The driving cycle the gov uses is just simply out of date, but even a upgrade won't fix the problem do to as stated, people drive differant in differant places. If you live in the mountains on dirt roads, well your won't do as good. But if you live in kansas and your area is paved, your going to do better.

Also as car become more varried in what they can do and their drive trains, (gasoline with an auto, vs say a powersplit hybrid with a turbodiesel) the model is going to be harder to fit.

Also models vary so much. Look at any one model but then look at how much you can change with options. You can had 500+ lbs to an SUV just optioning it from the base to the top end with all the power features and such. So even in a model you get lots of differance, even if the engine and tranny are the same.

And yes I'm sure many people will say my 19xx gets this many miles per gallon but my new one gets far worse. Yes this is true, but thats because makers have tossed mileage for emissions, which is a very good thing, and in doing that cost some mileage (aside from CO2 the other emissions are not directly linked to mileage, sometimes you hurt mileage to reduce emissions). Also new cars are so much safer to do more structure and such. Your 80s Japanesse cars were tin cans, they had to add a lot of weight to make it safe.

Things also apply to trucks vs cars. Most people who buy a truck/suv find that it gets better mileage then listed, few will get under 20mpg, just that the fed test isn't freindly to trucks, and some people are just morons and can't drive a truck and get good mileage. But for that there is the inverse and people who drive econobox's and don't get crap for mileage and no where near what it's listed to get.

If you get in mid 20s mpg with anything, be ok with that, into the 30s, great. For most people the differance doesn't relate to much money saved. Hell, if you buy a bottle of water out of machine, or a coffee at starbucks everyday you wasted more money then the differance in your cost driving to work that day.

Re:Possibly the best post on /.

Originally the "cash back"/tax deduction/tax break (call it whaterver you want) were put in place as a farming policy in the mid 1970 to help enabling farmers buying a decent (in this case decent as in manufactured in USA) truck.
However, heavy lobbying (GM, C and Ford) managed to get defense contractors and other contractors, landscapers included in the scheme.
In the late eighties creative accountants started to include ordinary companies like small entrepenurs and got IRS approval for this. When the SUV market exploded in the nineties it became common for everyone with a small company (dentists, doctors etc) to get the tax break.

It's allways possibly to debate what came first; the tax break or the SUV (as an evolution from the truck and the station wagon)?
I think the SUV would have appeared sooner or later as an evoutionary thing within car industry but it would never had gotten so widespread without the tax break. And the truck segment would have been far far smaller than today.

The tax break is a protectionistic piece of shit mutated far from the original concept without any thought of the consequences, be it environmental, energy policy or foreign policy. If someone where to write a book on how special interest is allowed to corrupt US policy on several areas the SUV tax break case is a perfect example.

And BTW to the root poster that brought up this topic: The tax break is far greater than $4000. According to Taxpayers for common sence it's possible get tax break around $100000. They site an example [taxpayer.net] where a business owner can buy a $110000 Hummer and deduct $106000.

Re:All these SUVs are beginning to embarrass me...

Man you gotta get laid, quit drinking, or do something to loosen up. I'm so sick of people blaming SUV's for all the world's problems.

Look around your home. Everything is made from plastics nowadays, and plastics come from petrochemicals. Carpet, shoes, jacket, tv, CD's, DVD's, chairs, aspirin bottles, backpack, remote controls, lampshade, joystick, keyboard, mouse, just to name a few. Are you old enough to remember when softdrinks all came in glass botttles, or do you think they always used plastic?

Our demand for all things derived from crude oil has increased, not just gasoline. Even natural gas was burned off as a waste product 30 years ago, now it's used as a fuel and new supplies are required to keep up the demand.

If everything you own is a hand-me-down or a reused item, and you don't drive, heat your house with wood and not oil or gas, and you don't purchase any new plasticy consumer goods, then your preaching has merit. If not, and I suspect this is the case, stop being so ignorant and don't give me your higher and mightier than though SUV's-are-evil speech. You're contributing to the demand for petroleum products just as much as anyone else is.

Re:All these SUVs are beginning to embarrass me...

According to Time Magazine, gasoline accounts for 44% of US oil consumption. Diesel fuel, heating oil account for another 19%. Plastics procution is buried somewhere in the "other products" category, which accounts for only 15%. So while I can't say off hand exactly how much petroleum is used for plastics, I CAN say that at least about three times as much is used for gasoline.

Look, you're right that it's a multifaceted problem. Probably heating and electricity production (in which oil plants play a non-negligable roll) are even bigger concerns than plastic; however, gasoline is the largest single contributor.

More over, gasoline consumption is probably one of the easiest areas in which to make significant improvement. Unless you build your home or make major, costly, renovations, efficient heating and cooling can be fairly difficult. There are some simple things you can do, but you can only make so much headway. Electricity consumption is much the same situation, and effecting how it's produced is a more long term project.

On the other hand, it's quite easy for most people (who don't need to do major hauling for construction or farming) to buy a vehicle with nearly twice the fuel efficiency of many SUVs, so realistically this is the best way to attack the problem in the short term on an individual level. So, to me saying "oh what about plastics and heating, etc." still is a pretty flimsy excuse for making such a wasteful choice.

Re:All these SUVs are beginning to embarrass me...

Would owning a smaller car to drive during the week, and renting a larger vehicle work for you? It wouldn't make sense if you have to load it up every weekend, but just a thought.

Also, you might check out the Ford Escape (a hybrid SUV) that will be coming out next year. 40MPG ain't bad for an SUV! Check out this [chippewa.com] article, for example.

about right

i drive a saab 900 SE turbo. mileage should be around 27 hwy, I generally get 27, and on long trips the computer reads 30+.

city gets lower than the 22 rating, around 18.

I drive a 2000 Chevy Lumina.

It's a company car with the 3.4 liter engine. I am a fairly assertive driver and put at least 25,000 miles a year on it. I've had 3 very similar cars over the last decade and consistantly get over 25 mpg in a mix of Interstate and light city driving. I think the operative phrase here is "Your mileage may vary".

For some reason I seem to get reasonable good mileage regardless of what I'm driving. At one time, years ago, I had a 1976 Mercury station wagon, totally a battleship with a 460 V-8 and managed to average 14 mpg with that boat hauling my 5 kids and wife. Again, I emphasize that I'm not an economy minded driver. I am a "Get from point A to point B" with a minimum of fuss and delay sort. I never get more than 10 mph over the posted limit, so I mostly go with the usual flow out here in the plaines. A little over a year ago I drove my mom's Buick to Arizona for her. It's got that nice 3.8 liter engine and is not a light car. I drove 1,750 miles in two days and got 28 mpg, but admittedly it's all Interstate driving, but out West traffic moves at 80+ mph. I was reall surprised. I've also driven some larger Chrysler products on long trips with mileages that were similar. I've concluded that modern cars do a pretty durn good job of fuel economy even in some of the larger configurations.

"Do the Right Thing. It will gratify some people and astound the rest." - Mark Twain

Ford Escord and Mini Cooper S

I'm a bit of a wonk when it comes to gas milage: I keep track of all of my gas purchases.

I used to have a standard 96 Ford Escort (no AC) that regularly got around 30-35 MPG in about a 60/40 Highway to "City" split. I can't remember what the EPA numbers were for that model, but I remember that I was around or slightly above them.

I now have a MINI Cooper S (fun f**king car). Under the same driving conditions I was getting about 23-24 MPG, which was lower than EPA. I have since moved and the drive is now 30/70 HW vs City and it has dropped to the 21-22 MPG range.

Re:Ford Escord and Mini Cooper S

You aren't that much of a wonk to record gas purchases. I do the same in a little notebook in my car. I take it and calculate the fuel economy on a near monthly basis and it lets me know if there's something wrong with my old '93 Nissan Altima.

It's really a quick and a smart thing to do and I encourage everybody to do it. Your fuel economy will be one of the first warning signs that your car is developing a problem. If that drops it's time to take the car to get looked at. Just a little time to save major money on repairs later. And if you go to sell your car you have a record of its health.

Re:Ford Escord and Mini Cooper S

Or you can dispense with the notebook altogether if, like me, you always fill your tank fully at the gas station.

When you fill up, the pump will tell you how many gallons you just pumped into your car. When I get back into my car, I reset the tripmeter (the "second" odometer which can be reset) after noting the number of miles I've driven since the last fuel stop. Then it's just a matter of spending the next minute or so trying to do the division as accurately as possible without getting into an accident.

This method is certainly no better than what the parent recommended, but it definitely requires less paperwork.

I also feel the need to say that there are a lot of very serious things that can go wrong with your car that don't affect the fuel economy --- just because you're beating the quoted fuel efficiency rating doesn't mean you don't have to look at other things!

About what I'd expect...

Car: Audi TT(6spd 225HP 1.8L turbocharged sports coupe). EPA: 20/28. Actual average for a tank has ranged from a low of 24mpg to a high of 33mpg. The 24mpg is a fairly even mix of city and highway driving. That value seems to correspond pretty closely to what one would expect from the EPA numbers. The 33mpg is all highway, of course, in sixth gear, with no turbo.

My experience

Of course, MPG greatly depends on how you drive, the state of the car, the fuel, the weather, traffic, and terrain.

The EPA numbers are a relative guide. They won't tell you exactly what you'll get for fuel consuption. However, you can easily use the EPA numbers to compare two cars' relative fuel efficiency. In fact, I submit that there is no better guide available for cars sold in the US.

Gas

They also depend on what gas you put in the car. Some cars do drive better on supreme.

When I used to live about 400km from my hometown, I spent the first while driving home on regular, it took about half a tank to get there (45L tank?)

However, when on a whim I tried "Supreme," it actually took me just a little over a quarter... so milage and bang-for-my-buck was actually better on the more expensive gas. Possibly this also has to do with the mountainous terrain and the fact that the gas gave me more power - not sure.

I do know that I regularly stick injector-cleaner in, so I shouldn't be getting plugged there. Therefore, I'm willing to state that better gas can give you better milage (and not all gas stations give the same quality gas either)

Re:Gas

They also depend on what gas you put in the car. Some cars do drive better on supreme.

Higher compression engines, or more highly-tuned engines, need higher octane gas. Mostly, it's to prevent knocking (early detonation caused by compression rather than spark). Any good car of relatively recent make (at least the past 10 years, if not older) will have a knock sensor to adjust for lower-octane gas, at the expense of fuel usage. However, if your car is designed to run on 87 octane, higher test gas shouldn't make much of a difference.

Possibly this also has to do with the mountainous terrain and the fact that the gas gave me more power - not sure

Actually, there is less energy potential per gallon in higher octane gas than lower. That's not really an issue, though. What most likely happened was that previously you were not using the proper octane-level gas for your engine's compression and the ECM was adjusting to a less optimal program to compensate. As a side note, race gas and airplane gas have much higher octane ratings due to the use of lead additives. Don't try this in your car. Lead will kill your cats in a matter of minutes, not days or months. Race cars and airplanes don't have catalytic converters.

I do know that I regularly stick injector-cleaner in, so I shouldn't be getting plugged there. Therefore, I'm willing to state that better gas can give you better milage (and not all gas stations give the same quality gas either)

First off, most additives are snake oil. Pretty much the only thing that works is Techron (and knock-off brands using a similar formulation). If you fill your car at a station with Techron or a similar cleaning additive, there's no reason why you should have to add injector cleaner on your own. If you must, an application once or twice a year is sufficient. Any more often and you're just throwing money away. As for better gas giving you better mileage, that's true up to a point. As I mentioned already, higher compression engines require higher octane fuels. If you're not using the right fuel, your engine will operate inefficiently. Using a higher octane gas than is required is useless if your car can't adjust its compression ratios to make use of it (ie, putting 92 octane gas in a low compression engine like many American-made engines isn't going to help anything, while putting 87 octane in a high compression Porsche engine is going to give you poor performance and mileage). If it's bad gas you're worried about, the most common problem is too much water in the gasoline. You can solve this problem with an alcohol additive to "dry" the gas. Other problems like too much sulfur (I believe that was the problem recently with some gas down in Florida, among other places) don't have an easy remedy, and all you can do is stop driving, have the car towed, and empty the tank. Run a few tanks of good gas through the engine and it'll be fine.

As others have already stated in this article, there are many other factors to consider. Low tire pressure, dirty air filter, oil, oil filter, bad alignment, too much weight (of the driver, passengers, and any cargo), etc will all have an effect on your mileage. Also, most cars will get their best mileage at low RPMs. If you can cruise at 2000RPM, you're going to get much better mileage than cruising at 5000RPM (just be careful -- you're going to be in a high gear to cruise at such a low RPM, and trying to accelerate in that gear could cause you to lug your engine. This is more important in high-revving, low-torque engines than it is in low-revving, high-torque engines).

Links:

• HowStuffWorks on gasoline [howstuffworks.com]
• Gasoline FAQ [faqs.org]

Re:Gas

"Supreme", "92 octane", "premium", whatever you call it- is not *better*. It has a higher octane rating. Oddly, that just means that it's more difficult to ignite it.

If you're getting better gas mileage with it, that means your engine is probably suffering from pre-ignition, aka "pinging", without it. It doesn't mean the higher octane gas has more energy, just that you don't have a cylinder or two working against the rest of the engine. I used to have a jeep that was terrible with pinging unless I used 92 octane, so I am familiar with the situation.

But for most cars, the 87 is just fine. Note that the 92 doesn't have more cleaners or anything else in it. For the vast majority of cars, 87 works fine and there is no reason to get ass-raped by the filling station for 92 octane. It's like shoe size: a size 13 shoe isn't "better" than a size 8, unless your feet are size 13. If your feet are size 8, however, the size 13 doesn't offer you anything more.

The FTC has considered regulating the oil industry by disallowing any terminology suggesting that higher octane is better.

The Low-Down on High Octane Gasoline [ftc.gov]

I get reasonable mileage...

I don't recall the EPA sticker figures on my car, but I have a '98 Saturn, and I get 31-35mpg.

Of course, I drive like a little old lady from Pasadena (not the one of the Beach Boys fame, though). I usually skip breakfast (perhaps it saves weight?), and my neighbors cats are grey...

Re:I get reasonable mileage...

'03 Vibe GT, I get from 26 - 28 mpg most of the time. long highway trips I might see 31mpg. Usually just a bowl of cereal for breakfast. Neighbors on both sides have Marmalade cats, as do we. Do you think its the cats?

Look it up here

http://www.fueleconomy.gov/

Depends on Cat

Or is the answer simply 'it depends on how you drive, what you had for breakfast, and the color of your neighbors' cat?

My mileage dropped drastically after pieces of the neighbors' cat got caught in the air intake.

If it hadn't been a black cat I wouldn't have run over it at night.

So, yes, mileage depends on the cat's color.

70 MPG in the Insight, depending on weather!

When the weather is warm, and that seems to be the biggest factor, I get the EPA-rated 70 mpg or more in my 2000 Honda Insight. 55 on cold winter days.

Driving at moderate speeds is also a big factor.

EPA fuel mileage is a scam...

It's a travesty when a 3800-pound 2004 Pontiac GTO (classed as a compact car) that gets, in reality, about 20/26 is "rated" by the EPA at 15/18, and gets a $1000 "gas guzzler" tax...while the 8000-pound Ford Excursion in the next parking spot gets fuel mileage so bad that it isn't even rated...but is eligible for medium-duty-truck tax writeoffs, and no "guzzler" tax. The whole system should be dumped in favor of vehicle choice, not artificial limits put on cars by the government.

Not a scam, just outdated

The whole system should be dumped in favor of vehicle choice, not artificial limits put on cars by the government.

The truck exemptions (that allow for SUVs to have pretty much any fuel economy [or lack there of]) came from the late 1970s when most trucks were used by farmer and construction workers. The idea was to help those people, who generally are involved in small business and make peanuts anyway.

Times have changed, now everybody and his brother has an SUV or pickup truck (even if they don't admit it). The regulations haven't changed, not because of a scam, but because the federal beaurocracy is a mess. Sure, the oil-loving administration isn't going to hurry along any changes, but they aren't doing anything actively to prevent such changes either.

Re:Not a scam, just outdated

You also forget the death of the Station Wagon. It is the loss of this vehicle class (primarily due to fuel economy regulations) that has pushed SUVs into the mainstream. If you have more than a couple of kids, you need to have a larger vehicle and an SUV is now the only choice you have, unless you buy a bus.

The station wagon was a standard staple of middle America for many years, and helped haul millions of children to football and baseball practice. If a car company wants to sell them in America, they are forced by regulations to sell several cheap cars (like the Geo Metro). SUVs don't have this same restriction. Mini Vans also help cover some of this, but even a Mini Van doesn't deal with everything you could haul in an old fashion station wagon. That's why I drive an SUV right now.

Ahh, so YOU'RE one of those crazy speeding people!

(I've had coworkers and friends say 'woah!' more than I'd like to admit *grin*)

Ye who speeds, cuts people off, and winds through traffic, is the first to reach the red light.

A healthy car means good milage

I can't speak on the newer cars around since I drive a '93 Nissan Altima. My milage is good, averaging around 30 mpg. I have no idea what the EPA sticker is for that year, but most people that have older Altimas in decent shape seem to get near that. Given that many new cars appear to have 28 mpg for highway driving I'd say I'm doing pretty well.

I'd have to say that the biggest part of keeping my fuel economy up is keeping my car in good shape though. I had the muffler on my car die recently, the pipe basically decided to rust off the muffler body. I noticed a little bit of noise, but the pipe was still in the muffler and they were both connected to the car so nothing looked out of place. The big tip off that something was really wrong was the reduced fuel economy. Took it in to a trusted mechanic, got it fixed, and the mpg was back to where it should be.

Also, keep your tires inflated to where they should be. I'm told this is the best way to increase fuel economy.

same story here

Similar for me. I only keep track of my mileage when I'm trips, but my 28 mpg highway rated sedan consistently gets over 30 mpg, and I've hit 33 mpg several times.

I've heard it said that a typical vehicle gets the best mileage at 55 mph, and that for every 5 mph above or below that, subtract 1 mpg. I'm an aggressive accelerator, but I rarely go much over the speed limit any more, so this might be where some of my luck comes from. In fact, the best mileage I've ever gotten was when following my father-in-law when he was driving a moving truck at about 55-60mph the entire stretch from Chicago to Kansas City.

depends on technical factors

how loaded your car is, how much you drive up hill, how often you brake or decelerate, now hard you accelerate, which way and how hard the wind is blowing (literally), how bald your tires are and whether they are aligned, is it a hot day, cold day...the list goes on.

seriously there are tons of physical factors that will affect your mileage. The EPA estimates are just that - estimates. Values that are in the ballpark of what you can expect to get.

93 vs 02 EPA mileage

My previous car was a '93 Ford Probe. It consistantly beat the EPA fuel mileage estimates by about 3-5 MPG My current car is an '02 Dodge Neon. It's consistantly worse than the EPA estimates by about 3-5 MPG.

Reading some of the other posts, it seems that older cars beat the EPA mileage and newer cars do not. Is it possible that the EPA changed their methods for estimating mileage?

Side note: I sure miss my '93 Probe. Sniff.

Hi Timmy!

~ how does the Slashdot readership fare when it comes to EPA sticker vs actual experience ~?

The slashdot readership has probably faired the same since this story originally ran [slashdot.org]. Oh, wait.

My Hybrid Civic

My '03 Hybrid Civic had (I think) 48/47 on the sticker. When I drive it, the "MPG" meter in the dashboard ends up around 42-46. At the pump, I actually get 39-44.

How the English improve their MPGs

You Americans could learn a lot from the rest of the world when it comes to getting more MPGs.

Just do what we do -- use a bigger gallon!

Low-tech solutions to hi-tech problems :-)

Author fails to realize one thing..

Toyota doesn't mess around. They've also sold [iht.com] the hybrid technology to ford. Let's not forget that toyota is also releasing a hybrid [auto123.com]which does 0-60 in 4.03 seconds and tops out around 155mph. Don't walk away from this thinking Toyota is maniacally evil, if anything, they've got their shit together more than most automotive companies.

Sorry for being a toyhead, they please [mr2.com] me [toyota-supra.com] immensely. Something tells me, if the author of the article was driving a volta, miles per gallon would be the least of his worries. I think toyota pretty much tops the list of fuel economy, on any playing field. Prius wins in my mind, not strictly because of fuel consumption, but by the name that's behind it.

Re:Author fails to realize one thing..

That's not exactly true. [usatoday.com]

02 Prius

In cold weather the Prius got between 35-40. Now that the weather is nice, I've been getting 48-52 for my commute. My wife who does more short trips and sits at lights with the AC on gets quite a bit less. The first 5 minutes in the Prius is very poor (about 25) as it is agressive in maintaining the engine coolant temprature for the low emissions. If it was designed for millage instead of emissions, it could do a lot better. Where the car does a fantastic job is in stop and crawl driving if you are not using the AC. It does that with the engine off 90% of the time. Conventional cars don't fare nearly as well as you are stopped too short to shut off the engine and sitting idling is zero MPG. An extra bonus is the car doesn't overheat in those conditions like my old car did. A warm day and stop and crawl traffic would usualy result in some loss of coolant.

50 MPG Jetta TDI

I drive a 2000 Jetta TDI, and I am no light foot with it. The EPA rating for the car is 42/48 and my personal lifetime average for the car is currently at 47.1 MPG. On longer trips of predominately highway i have had mileage about around 52-53 miles per gallon, this is with cruising at 70 mph. Got to love driving a diesel car :)

MILEAGE DEPENDS ON FUEL QUALITY!!!

While it is true that with age a cars mileage will tend to get worse due to carbon build up, what really effects your mileage is the quality of fuel that you use!! The higher the octane does not matter, but which brand most definitely does. For instance, at the risk of sounding like a corporate sponsor, Shell gas on average gives me about 30-40 more miles per tank than most gas.

Corvettes

My 90 ZR-1 was stickered at 16/25. I got 18 city, and from 27 (80mph) to 33 (65mph). Not too shabby for 375 hp.

Its replacement, a 2004 Z06, is stickered at 19/28 and I'm seeing 18.5/33-35 quite respectable and 405 hp to boot.

I love it when some econo-box criticizes my sports car as a gas guzzler and finds out I get better milage than they are :)

My Jetta TDI gets 54 MPG on the highway

My diesel 2001 Jetta TDI gets about 54 MPG for highway driving (doing 75+ MPH), and about 48 MPG in the city. It has 90,000+ miles on it, and still drives like a champ. Plus, diesel prices fluctuate less than gas does.

Before people start to complain about environmental concerns, do the research first.

http://www.tdiclub.com/
http://www.biodiesel.or g/

I did a lot of research when I bought, due to my long commutes (150+ miles/day), and I save, on average, between $250 - $300 per month, which essentially paid for the monthly payments.

Great car. They also have Diesel Golf, Beetle, and Passat models, if the Jetta doesn't float your boat. Worried about not being able to find diesel? When my low fuel light comes on, I still have a 2 gallon reserve, or about 80 miles in the city, but in reality, it's not that difficult to find diesel.

They're definitely worth checking out. I plan on being able to keep the car for a number of years, as the engines last forever. Sorry to sound like a diesel advocate, but it's a great, comfortable car.

I drive a 1994 Audi 12V V6

it's the 90CS Quattro Sport, 5 speed. The car itself weights just shy of 3500 lbs, and then there's occupants. I'm still amazed at how agile it is with all that weight being pulled around by a 2.8L engine. The AudiWorld page [audiworld.com] for my particular car says 19mpg city, 24mpg highway but I can get closer to 30 in the city if I manage to not do craziness around town. I tend to shift at lower RPM's, I catch some flak for it but I go to the gas pump half as much as they do.

Everyone that's driven this car is very surprised because it doesn't look like much but it can handle the rice boys fine. If it's in anything except clear conditions, don't even try. You've never lived till you spin all 4 wheels on gravel or ice while it gets grip. I can't imagine what putting a supercharger on there will do. I've had the car for over 2 years and I still get goosebumps from the performance.

Most of us drive like we own a race car

The reason most people don't get the advertised mileage is because they goose it at most every opportunity and race up to the light and then get on the brakes. More sensible driving patterns will get better mileage. I like the hybrid cars because they provide real time feedback both in text and graphics as to your mileage and fuel consumption. I wish conventional cars would do this also.

I Love My Bike.

I'm riding a Honda Rebel around town now. The car I replaced with the bike was a 1992 Toyota Corolla that pegged in at about 30 MPG on the highway and 21 on the city streets. Since most of my driving was city streets, I'd have to fill up every week or less, depending on the travel schedule. The cost of gasoline now would make my average trip to the station about cost between $25 and $50 per week, again depending on how many times I needed more gas.

I've had the bike for about 2 months now, and I think I reached $50 total in gas this weekend. I haven't figured out the total mileage yet; when the tripmeter reaches 150 miles, I get paranoid that I'll have to cut in the reserve (2.1 gallons in the primary, .6 in the reserve) so I fill up. I always go in and put $5 on the counter, fill up the bike, and go back and get my change. I'm guessing that I'm hovering around 80 MPG.

And I'm getting a tan while I run errands.

My mileage

My preferred method of transportation gets 1.2 gallons per mile [toltecimages.com]....

Which is better than a hybrid car [trainweb.org] for certain numbers of people.....

Driving Habbits

I drive a 2001 Audi S4. It has a V6 twin turbo manual 6-speed. EPA says 17 city, 24 hwy. I drive mostly highway. During the summer months here in FL (lots of A/C), I tend to get around 20mpg average with my normal, very aggressive driving.

Altough, around 2 months ago I performed a 'test'.

During the whole tank of gas, I accelerated as slow as I could never pressing the gas more than 1/4 of the way. I knew the lighs were going to turn red, so why accelerate? I eased on slowly and came up to the red using as little break as possible (a waste of energy)... maybe even rolling into the light as it would turn green and _then_ slowly accerlerating.

On the highway, I would stay in the right lane (insane for me). The speed limit is 70, but I would hold 63.

For the tank I averaged 35mpg.

Moral of the story. The car you choose does have a lot to do with your final MPG. But your driving habits also have a huge amount to do with your fuel usage.

A few tips on improving your fuel efficiency:

1. Check your tire pressure at least once per week, preferably before you drive the car for the day. If the tires are properly inflated, you get lower rolling resistance, which can improve fuel efficiency as much as four percent.

2. Change the air filter once every three months. With a clean air filter, you get better engine breathing, which can improve fuel efficiency several precent.

3. Keep the fuel-delivery system clean. That means you should run something like Chevron's Techron additive to your fuel about three times per year to keep the fuel injectors clean. Also, consider having the fuel injectors removed and cleaned manually by a good auto repair shop every 36,000-40,000 miles or so. A dirty, potentially-clogging fuel injector can not only hurt fuel efficiency, it also hurts overall engine performance, too.

4. Replace the spark plugs at slightly shorter than manufacturer-recommended intervals. An improperly-working or worn spark plug can hurt fuel efficiency and overall engine performance quite a bit.

5. Don't drive too fast. Keeping the speed under 75 mph usually helps fuel efficiency since you're dealing with less air resistance when running at lower speeds.

6. Keep the windows closed on a sedan or coupe type vehicle if you're travelling above 40 mph. An open window causes considerable air resistance at higher speeds, so much so that you actually use less fuel with the windows closed and the air conditioner running than having the windows open when you're driving on the freeway.

Economical?

36.3 miles per gallon is the most economical mileage you got? And that's supposed to be especially economical? What kind of cars do you Americans drive?!

I get twenty kilometers per litre, that's about fifty miles per gallon, on average, and that's with a very ordinary turbodiesel, nothing fancy or especially fuel economic (and a pretty quick driving style).

Re:Economical?

What type of car do you drive and in your book, does a gallon equal 128 fluid ounces? On a separate note, Americans drive whatever car they like best. Sometimes it is a compromise of bang for the buck or practicality, but it will almost always be something that fits the driver. For instance, I just ordered a Mini Cooper S for my wife. The car's style fits her like a glove. The fuel economy of that car is just fine by my budget. I feel bad for people whose primary concern in owning a car is its fuel economy. There is more to life than efficiency.

Re:Economical?

And that's supposed to be especially economical? What kind of cars do you Americans drive?!

Ummmm, gasoline powered cars for the most part, and it's practicly impossible buying a new car with anything smaller then a 1.5l. Even Honda's new civic is a 1.7l. Some states can't sell TDI cars, only a handful IIRC.

Now, TDI would be nice, but let's look at the numbers.

A Volkswagon Bettle GL 5 speed runs $17,630 MSRP [vw.com]according to the website. Toyota has the Echo and Corolla at $10,870 and $14,195 [toyota.com] respectivly, a price diffrence of $6760 and $3435.

Corolla and Echo get about the same MPG, about 40 or so, you get 50 or so. Driving 300 miles a week for 52 weeks = 15600 miles. At 50mpg that would be 312 gallons of fuel, where 40mpg would be 390 gallons of fuel, a savings of 78gals a year using my numbers.

At present fuel for me costs about $2.00/gal. I would save $156 yearly on the TDI Bettle. It would take me 43 years to see a cost savings in the echo, 22 years in the Corolla. This is assuming I pay sticker price for a base model.

I'm not saying a TDI wouldn't be cool, it indeed would be. And 50mpg would be pretty cool too, but I have to look at the bigger picture here. The amount of money I save isn't enough to justify the purchace, and i'm a cheep bastard. I know many people, friends and family alike that drive SUVs or Trucks that get 12-15mpg. This is the 5+l engine class and is generally accepted as being piss poor.

Between 30-40mpg is considered to good to great, and it is for gas powered cars with 4cyl sub 2.2l engines. 40-50mpg is considered to be excelent but none too common in gas powered cars. 20-30 is probally about average IMHO, esp among midsized cars, esp those with v6 engines in the 2.5l range.

Re:Economical?

Well, come on, I use 15l/100km, and that's driving a European vehicle. Driving a heavy SUV and carting around heavy stuff all the time talkes fuel.

Note that US gallons (3.6l) are different from imeperial gallons (4.5l), so that can lead to some confusion between UK and US posters!

MW

I live in the EU, you insensitive clod!

But seriously, we have urban, extra-urban and "combined" mpg. I find that I get almost exactly the "combined" mpg from a car once it's been run in, and I don't do many long trips. On long trips the mpg is quite close to the extra-urban rating. The EU measurements are actually very good compared to the pointless "constant 30mph/constant 56mph/constant 70mph" figures that were used in Britain until about 10 years ago.

True fuel efficiency means...

In Finland we have SUBSTANTIAL Gas tax. That means MPG has real result in my pocket.
BAD MPG is from 70's soviet union made vehicles which is about 30 MPG and modern cars get around 60-70MPG. We pay 1.2 Eur/litre =~ 5.67$ /gallon. Most of it taxes.
If US would get anyway near similar TAX on gasoline [Passed with reduction of other taxes] Your thinkin 30MPG is good fuel economy would change. Also that would bring small shops closer to places where people live in order to reduce driving.