Gas milage ratings???

J

jackknife

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Oct 2, 2004
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In 2002 I bought a new Toyota Tacoma to replace my aging high milage 1990 Toyota pickup. The new tacoma with the 4 cylinder was rated 24mpg city and 26 highway. I can manage about 20-22 city and about 22-24 highway, but thats it. Oh, thats 2 wheel drive by the way.

Now I know the EPA gas milage ratings are not too real, but I was wondering how close some of you have gotten, and has anyone ever really made the mpg that the trusty gov't has told us we would?
 
The EPA rating are not meant to be absolute. They are relative. For each type of vehicle, the measurments are done in a very consistent way from model-to-model. As a result, if you are shopping for a new light truck, for example, and you notice that the Toyota model is rated at 24/26 and the similar Chevy is rated 20/22, you know two things: First, this type of vehicle doesn't do substantially better on the highway vs. city. And, second, the Toyota gets a bit better gas milage than the Chevy. Because the tests are done in a consistent way, the ratings allow you to compare two models. That's all. Because the tests are not done in exactly the way you drive, they are not an indication of exactly what milage you will get.

If you have a pickup truck and you do not use your bed day-to-day, consider removing the tailgate or replacing it with a net (which can also be removed and stored when not in use). This will add several miles per gallon to your truck, especially on the highway. Even better: install a bed cover. The pickup truck shape with that giant open bed in the back, is about the least aerodynamic vehicle that could possibly be designed.
 
I find it hard to beleive that a vehicle will do only marginally better on the highway than in the city. Its probably the way you use gas. Some people just dont know, but the best way to get the best milage is at 56 MPH (usually highway stats use this speed as its the most efficient). Get up to 56 and let your foot off the gas ever so slightly, bit by bit, until you see a drop in speed. Then push down a few mil until the speed stays at a constant 56. You are now driving at optimum fuel efficiency for you vehicle.
 
Gollnick, re: the bed cover, removing tailgate, etc. I was under the same impression. However, a few years ago I read an article that said a windtunnel test showed the truck was more aerodynamic with the tailgate up than down - something about a pressure bubble over the bed. Can't remember where I read that and haven't heard it since. Anyone know the scoop on this?

As far as the EPA ratings, Consumer Reports wrote not too long ago (end of '04) that the EPA testing procedure is under review b/c the figures are not too accurate in reality. I'd say you sound pretty close. My results have been the same as yours.
 
Tail gates - The other thing to consider, is that whatever structual qualities the frame and body was designed for will be hosed up to some degree without the tailgate.

I think the EPA figures are at least 20% overrated. There was a news tory recently about how some hybrid model was getting around 28 MPG real world when EPA came up with something around 50 MPG. Buyers weren't too happy.

In our case we have a jetta TDI, and I don't believe we have gotten below 40 MPG and a couple of times almost 48. Diesel quality varies so widely even between summer and winter it's even harder to get any kind of precision.
 
Real-world mileage is always going to differ from laboratory figures. Ambient temperature, driving conditions, tire inflation, wind, load....

It's always a good thing to keep track of, though, as sudden changes can indicate problems.
 
if you were to spend a couple hundred dollars and put a K&N or Air Raid cold air induction system (changes your air filter and plumbing from it to your engine) you could feasibly see an increase of 5-15 mpg. A friend of mine was getting 13 mpg with a newer durrango, put one of these on it and increased mileage to 19 mpg
 
i would think for it to go up 50% his old airfilter musta been dirty/etc, thats a lotta diff w/the K&N, i put one on my vette and it went up 1-2 MPG in town, did he put an entire system on the durango or just a filter?

my vette does lots better hiway, about 15 in town, 28 on hiway, of course that may be due to the way i drive in town lol, but even going easy i dont think it ever goes over maybe 17 in town tops.

hey jackknife ya live in germantown MD?? one of my old flames lives there lol.
 
Corvettes get excellent gas mileage on the highway because they are geared so tall. At freeway speeds the engine is just barely off-idle.

This is why there is no universal "best gas mileage speed" that can be applied to all cars. Even vehicles that are otherwise identical can display very different fuel economy with changes in their gear ratios.

This is also why it is not uncommon for a vehicle with an optional larger engine to get better real-world fuel economy than one with the smaller base engine. With a sufficiently powerful motor, you can run at much lower engine speed for a given vehicle speed. This can be more efficient than running a smaller powerplant that you have to keep high in the rev range to get adequate power.

So, if you want to save money on gas getting the smallest motor available is not always the best choice.
 
a few years ago I read an article that said a windtunnel test showed the truck was more aerodynamic with the tailgate up than down - something about a pressure bubble over the bed. Can't remember where I read that and haven't heard it since. Anyone know the scoop on this?
Click to expand...
I've heard the same thing, on Click and Clack and another newspaper article. With a tailgate, the air comes off of the cab and over a 'pillow' of air in the bed, then off the back of the truck. Without a gate, the air off the cab is forced into the bed where there's more friction and more air disturbance.

Doesn't matter on my truck, a '94 F150 4WD with a shell. It gets 13 no matter what. 13.8 on a good day; 13.2 on a bad day. It only has a 5.0, so has to work hard to get a vehicle that heavy moving. Plus, trucks aren't very aerodynamic anyway.

I've had two Mercury Cougars and a Lincoln Mark VIII that have done better than the EPA. When I bought my first Cougar, an '86, 5.0 V8, the first year with real fuel injection, the dealer told me it'd get 20 at best. On the highway, it got 30 all the time. 20 gallon tank x 30 mpg, you could drive all day without stopping.

Dissapointingly, my '94 Cougar, 4.6L V8, had a smaller tank and got worse mileage - probably because the car became much heavier. 28mpg is about the best it could do, and it only had an 18 gallon tank.

My current car is a '95 Mark VIII, 4.6L DOHC V8, 280HP. On the interstate running at 80mph, she gets 28-32 mpg. I attribute that to the cleaner high-octane gas she burns, and the low rpm. At 80 mph she's turning barely over 2000 rpm.

Unfortunately, and disgustingly, I've noticed many of the 'economy' cars don't get very good mileage, especially on the highway. The reason, their weenie little engines are revving high to run at higher speed limits. They do get better in town, where the cars' light weight is well-matched to the stop-and-go type of driving.

The solutions I see, merely steps along the way, to improve mileage in automobiles:
1- more aerodynamic vehicles
2- more widespread use of high octane fuels, and development of cleaner and more powerful gasoline
3- lower revving engines

Just my ideas. They seem to be the opposite of current trends, so I'm not holding my breath.

-Bob
 
The real advantage of high-octane fuel is not that it is inherently cleaner or has more internal energy, but that it is more resistant to detonation due to heat and compression.

This allows you to run a motor with a higher compression ratio, which in turn allows you to make the most of the energy that is in the fuel. Being able to more efficiently extract the energy in gasoline is what allows you to produce more power and lower emissions.

However, if a car is not designed with a high compression ratio that would require high-octane gas to be used, then there is no advantage to using it. Running 93 octane in a car that works fine on 87 octane is just throwing money away.

BTW, I'm a big fan of the Mark VIIIs. Absolutely beautiful and unique cars, even if they do occasionally have too much "character" for their own good.

I was actually looking to buy one for myself, until I happened accross a '77 Mark V for sale. I get 18 mpg on the freeway, which isn't that bad for something with a carburated 460 and a 3-speed automatic. Actually, it's better than most modern trucks and SUVS which weigh much less and have smaller EFI motors (that make far less power) and overdrive transmissions.
 
My 1997 Ford Thunderbird (4.6l DOHC v8, running on mid-grade, relavtively low miles-- just about to hit 94k) gets around 15mpg city, but actually gets around 25 to 30mpg on the highway. On long trips I can get around 500 miles to a tank, but I usually get no more than 220 on my usual home to work and back route.

I'm considering getting a good cold air intake to help fuel economy. I don't really care about the added performance from the air intake, I'm happy with my 210hp (I can get to 60 in just under 6 seconds, and this car is stock with the factory sport package).
 
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