Graph of MPG/fuel economy vs. speed, 2004 Aveo sedan (automatic)

[MetroMPG]

Here's a graph of what MPG (U.S.) you could roughly expect to get at a steady speed (cruising) in similar conditions with a 2004 automatic.



(Reposted with permission: by "slobro" from: Speed vs. Fuel Economy - 2004 Chevrolet Aveo sedan (1.6 L, 4-sp automatic)- EcoModder.com )

Readings were taken with a ScanGauge calibrated to this car, repeated over the same test route, with the reading reset & read at the same points along the route.

Note the best fuel economy is in the highest gear with the torque converter locked at the lowest engine RPM. Speed kills... MPG! Once in top gear, it only goes down as MPH goes up. (This would be the same trend for manual transmission Aveos too, though the MPG figures would be a bit higher at a given speed.)

A/C was off for the test.

Test conditions:

Temp: 69F
Pressure: 30.29"
Avg Wind Speed: 2.53 mph
Road Length: 0.85 miles, slightly inclined

Raw data:

Speed(mph) South(mpgUS) North(mpgUS) Average(mpgUS)
__________________________________________________ _______
25-------------38.5-------------40.5-------------39.5
30-------------40.3-------------43.3-------------41.7
35-------------41.2-------------45.6-------------43.3
40-------------40.1-------------47.0-------------43.3
45-------------38.7-------------45.1-------------41.7
50-------------41.5-------------46.7-------------43.9
55-------------38.9-------------42.0-------------40.4
60-------------36.2-------------38.5-------------37.3
65-------------33.7-------------37.2-------------35.4
70-------------32.8-------------35.1-------------33.9

(More speed vs. fuel consumption graphs: Speed vs. MPG charts (post 'em if you got 'em) - EcoModder.com )

[MetroMPG]

Oh, and as for why there is a jump in MPG between 45 & 50 mph?

my car was in third at 45 mph (I don't like how my car doesn't shift earlier). At 50 mph is where I was at the lowest rpm range in the highest gear, hence the jump in fuel economy

[FlaAveo5]

If I could get HALF the mileage of what that graph says, I would jump up so high, I would see Seattle from Fort Lauderdale! I cant break 19mpg to this day, in my auto 2006 Hatchback. Never once past 20mpg in over 6 years. Thats driving like either a 90yo lady, or a kid hopped up on meth. Makes no difference, its 19mpg. Period. Thats why I bought this car, to get these numbers, never got close to them to this day. Anyone wanna buy a 2006 with 23K miles?

[cyber3d]

Oh man. Me too! I can't get over 21 MPG (avg) no matter what I do to the car, no matter how I drive! (I do use the airconditioner however).
2008 Aveo5 Auto

[Daox]

That chart is the mileage you get at that exact speed on flat ground. Accelerating and stopping use considerably more gas (thus lower city ratings than highway ratings). If you spent your entire tank cruising at the speeds above you'd see roughly that mileage. I can attest that its perfectly possible with the right driving techniques. I always get around 40 mpg with my Aveo, but I drive about 45 mph most of the way to work, so its fairly ideal.

[VaVaVeo]

I can maybe get 25 mpg, and I drove down to nearly an empty tank to see that result in my 2005 automatic. I'll hit 70 on the freeway and typically stay there, only going higher to break away from crowded traffic. I do a lot of short trips here and there in the city, but I usually get up to 40-50. I know city driving eats up a lot of gas waiting at lights and stopping at signs, but I honestly don't think that could cost me 20 mpg (equivalent of half a tank). I know there are things I can do to improve upon it - get better tires, change fluids and plugs and etc etc, but I just don't see how all these things combined could ever add up to half a tank worth of lost fuel.

Either I'm severely underestimating the impact a few seemingly minor faults and certainties or there are some highly inflated false claims put out by Chevy.

[Daox]

I know city driving eats up a lot of gas waiting at lights and stopping at signs, but I honestly don't think that could cost me 20 mpg (equivalent of half a tank).

It completely can eat up all that mileage. I mean look at all the new cars even with their '40 mpg highway' ratings, but barely eeking out mid to low 20s for city mileage. That is the penalty for idling and using your brakes so much. Commuting in a city takes rediculously small amounts of power when you look at it vs highway driving. This is one reason hybrids and electric vehicles get so much better city mileage than normal cars, because they can recoupe that braking energy, and they don't idle while waiting for a light. It really does eat up almost half your tank of gas.

[FlaAveo5]

Everyone blames me for my poor mileage. Because I only drive like 3 miles a day,'it doesnt get up to top engine temp.,it is all the stop and go,it is all the city driving,etc...' I still say it should give me low 30's with the way I drive, not like a nut. If I was driving like a 18yo zooming around, and carrying around tons of junk in my car, then maybe low 20's. It is old engne design and I accept it.
But to think I gave up a nice 'collectable' Ranger Edge for this car, to save money during the first 'oil crisis'....and I got better mileage in my turck with a big V-6, and it would now have maybe 30K miles on it. Well, this one stays with me, till it doesnt run or it gets crushed by someone. Its paid off, and still 99% reliable, cant do much better than that.

[MetroMPG]

Because I only drive like 3 miles a day,'it doesnt get up to top engine temp.,it is all the stop and go,it is all the city driving,etc...' I still say it should give me low 30's with the way I drive

Not going to get good mileage in any vehicle in those conditions. My mom (who literally drives like a granny! ) got low 20's MPG in her Corolla in similar use.

Its paid off, and still 99% reliable, cant do much better than that.

That's the truth.

[MattHamby]

tire inflation is critical as well! I went one tank of gas with under inflated tires on my 94 Metro, the result was 6mpg - it was low by about 8psi or so, everything else was my typical driving, timing on the engine is critical also - I did an engine swap out not to long ago, it run fine (so I thought) for about 3 tanks of gas and the MPGs were in the mid to high 30's. I set the timing correctly and now I am currently getting and average of about 44mpg. It's funny to see how much little things do effect the MPG.