Good gas mileage?

As it seems that I am constantly pumping money into my black hole of a gas tank, I wanted to know how many miles a full tank of gas lasts me. I did an admittedly rudimentary expiriment, and I have some raw data, but I still don’t know if I get good mileage or not.

Here’s the deal: I purchase a full tank of gas for $20. I buy Supreme (my car is old and runs better on it) at $1.579 a gallon. This buys me 12.66 gallons (with the little hat over the .66) - 20/1.579.

Then I kept track of how many miles I drove on that tank. Grand total? 176.9 miles. So 176.9/12.66 = 13.97 miles per gallon.

How good is this? My car’s old and I’ve always thought of it as a gas hog. But is this good mileage per gallon? I’ve researched it but all I get are comparative listings, and I would rather now what some of you car experts out there think of 14 miles/gallon, or 177 miles/tank.

Since I know at least 90% of Dopers know more about cars than me, I welcome all advice or WAGs.


I usually take mileage by filling up the tank, resetting the small odometer, then after the tank is empty refilling it again. Number of miles divided by number of gallons in second fill (the number you had to use) equals miles per gallon.
Anyway a new corolla/civic get about 37-40 right? If you drive a lot maybe a new car is in order. Hell, my 95 corolla gets about 30ish city and about 38ish highway. Maybe a used corolla is what you need?

That said your gas milage is not that bad. I used to have big fat 8 mile to the gallon car. varoooom!

What car, what year, what engine?


Oldsmobile 88 Grande Royale, '89, V-8 engine.

30 m/gallon? Holy shit! I can’t afford a new car or even drive less (I commute 40 miles back and forth to school everyday). But that’s a lot! I’m impressed.

Wait, I don’t know if V-8 is right. It’s an 8 cylinder, 200 horsepower. I just bought a new starter. That’s about the extent of my car knowledge. :slight_smile:

Sara, 14 miles/gallon doesn’t sound all that great to me, but it depends on a lot of things - it may be perfectly reasonable for your car.

Firstly, what kind of car is it? What kind of mileage you should expect depends very strongly on that. I believe that some of the more gargantuan pickups and SUV’s have EPA ratings in the 12-15 mpg range, and some vehicles are down in the single digits.

If it’s an “economy” car, 30-35 mpg is probably a decent baseline, but many small cars can do much better than that; 40+ mpg is not unheard of.

My compact pickup truck ('97 Mazda B2300) gets about 23 mpg, if that’s worth anything as a reference point. I know this because I’m an anal freak, and I’ve recorded the odometer reading and amount of gas added at every fuel stop in the little beast’s life. :slight_smile:

I calculate the mileage the same way labdude does. It can vary somewhat from tank to tank, so taking a cumulative reading over several fillups can increase accuracy.

Basically, 14 mpg isn’t what I’d call “good”, but it’s not so low (without knowing what the car is) that I’d suspect something’s dreadfully wrong. Now, if a '00 Civic were turning in 14 mpg, I’d be concerned. On an older car, though, it may be about right.

For a big ol’ V-8, I’d say 14 mpg sounds about right. Certainly within the bounds of reason - big engines tend to be gas guzzlers. :frowning:

Depends on how you drive it, too.

I used to have a big ol’ Mercury Cougar with a 5.8 litre engine (that’s 351CI for you old folks). If I drove it “funly” then I got about 10-12 mpg. If I babied it and let people pass me at lights and drive exactly 55 on the freeway, then I got an incredible 20mpg on average on the freeway. Not bad for a land-yacht.

Yep, V8. Probably a 350, with 200hp in emissions-strangled form. 14 mpg is perfectly normal. My (pre emissions :D)Chevy 307 V8 gets 13-15; my Jeep 360 V8 got a steady 13.5.

I have a Jeep with the 4.0 Liter 6 Cyl, and am happy when I get about 15 miles per gallon in the city. On the highway, I get about 19 mpg. Fortunately, with an 18.9 gallon tank, I can go about 230 miles, on average, before having to refill.

And, just for comparison, I know someone who drives a Hummer, and he gets about 8-9 miles per gallon on the highway, but he can afford it. I’ve also heard some people with Dodge Durangos with V-8s complaining of single digit fuel economy, so there is much worse than 14 MPG.