Chevy Aveo: How to improve CITY MPG?
 

I’m beginning this thread to discuss every viable idea to improve FE on the Aveo.

We have a new 2009 Aveo 5 with automatic transmission that my wife uses for her daily commute to work. (She loves the car and we really don’t regret having bought it.) The type of driving we do with it is all ‘city’ (local streets with a stop sign on almost every corner and between 0-40 mph on major streets). We are only getting 22 mpg. The EPA estimate for city driving was originally 27 MPG, but eventually that figure was restated to be 25. For a car this small the city MPG is disappointing. I’m determined to try to raise the FE by at least a few MPG to the EPA estimate. I found the body of the car to be very similar to the Toyota Yaris, which I also drove before buying. But apparently similar models of competitors (Yaris, Honda Fit, and Kia Rio) all get better city MPG, if the EPA figures are to be believed.

Why does this car get such inadequate FE in city driving? Personally, I think it might be a combination of things. I’ve tried to list everything I could think of that might be a factor:

Weight
Aerodynamics
Transmission design
Engine control electronics

Comparisons with similar sized cars (all with A/T):

Aveo: 25 City / 34 Hwy.
Fit: 28 City / 35 Hwy.
Yaris: 29 City / 35 Hwy.
Rio: 25 City / 35 Hwy.

Aveo: 2557 lbs. 1.6 liter engine 4 speed
Fit: 2489 lbs. 1.5 liter engine 5 speed
Yaris: 2293 lbs. 1.5 liter engine 4 speed (plus overdrive?)
Rio: 2438 lbs. 1.6 liter engine 4 speed

Aveo ground clearance: 7.5 inches
Fit ground clearance: 6.5 inches (looks even less in front)
Yaris ground clearance: 5.5 inches
Rio ground clearance: 6.1 inches

An Aveo is about 250 pounds heavier than a Yaris, which also has a slightly smaller engine. The Aveo sits at least an inch higher off the ground than all the others. This makes it an easier car to get in and out of, and it’s better suited to clear low driveways and city streets that have dips and bumps without bottoming out. Considering our car is being used almost exclusively for city driving, that’s desirable; but possibly it is a disadvantage in the aerodynamic design. Also it is a VERY ‘tall’ car – to the extent that it’s difficult to reach the center of the roof when washing it.

Aerodynamically, there is virtually no air deflector at all under the front bumper of an Aveo. It’s just a huge, open space. The grille is similar in style to other much larger Chevy vehicles (in an attempt to make this small car look bigger?) in that it has a huge grille, again with much open space. To modify this I made an air deflector that now covers the vast area between the front bumper and its trailing edge where the wheel wells begin. Fortunately this can be done without obstructing anything related to routine service work. I also designed a lower grille block that is invisible, mounted behind the grille, and an upper grille block that is mounted externally and easily removable. (See it here) I happened to see a Honda Fit on the street and looked underneath the front end of it – it has the similar underside area covered by panels.

I doubt there is anything that can be done with the Aveo’s engine or transmission to improve FE. Ironically, the car has decent acceleration from a standstill (thanks to it being marketed toward American tastes and desires for power). Few Americans would buy one if it couldn’t get out of its own way. But I think that is a factor affecting fuel consumption. The Yaris and the Fit apparently both have more sophisticated transmissions, and that may be the primary reason for their superior FE. Apparently the Aveo is most similar to the Kia Rio in comparison, which is (maybe not coincidentally) also of Korean manufacture.

Now that it has about 1000 miles on it, I recently bought a ScanGauge in hopes of lightening my wife’s foot on the gas pedal. Time will tell, and I hope to see some improvement, however slight. I would welcome hearing from all other Aveo owners about their experiences and interests in mods that might help. Also, if anyone has one of the other brand models mentioned with A/T and does city driving primarily, I’d like to know whether all the EPA ratings are all inflated. :confused:

Here's a list of things that have a big impact on your city MPG, ranked from biggest to smallest.

driving style - very big in the city!
the weather
LRR tires
aerodynamics
weight reduction

I would set up a "trip MPG" X-Gauge on the ScanGauge to coach driving style, and look around the forum for driving tips.

Also ask yourself whether you really need rear seats, or rear floor mats. You could start deleting optional equipment, converting to manual steering, and removing the car's interior, but the wife probably won't appreciate that.

I've heard the Aveo delivers pretty disappointing MPG, and I guess you outlined why. Good luck with it, and if you drive well, I'm sure you'll be able to beat EPA during the summer.

I think the biggest thing to look into would be an engine block heater. On short city commutes the cold numbers kill you. Aerodynamics probably will not come into play much just do to the stop and go traffic that you mentioned. I would concentrate on getting the engine hot as quickly as possible.

Engine Block Heater
Grill Block
Front belly pan.
Tire pressures.

With an automatic it's critical to know your shift points and drive the speed that gives you the lowest rpm. That might not be the posted speed limit it might be a little ffaster or a little slower use the SG to see where it needs to be. Driving techniques are key for this environment. Both you and your wife study the 100+ driving tips to fine tune your technique.

Here's the garage listing at EM. They are respectable numbers. Just keep working on it.

Winter is a tough time for all.:)

I will, but I've only had the scan gauge for one tank of gas, and I need to calibrate it on the next fill-up. I currently have it set for mpg and for throttle position reading. I expect that the throttle position reading is the best feedback to re-educate someone who has a heavy foot on the gas pedal.

<LOL> She certainly wouldn't! She drives it about 98% of the time and it is a new car, so anything that would affect the look or function of it is out of the question. She didn't mind my adding the ScanGauge, but after 30 years of marriage, I don't want to press my luck! :o

I'm already doing everything but the block heater. I thought of it, but it won't help too much in our specific situation. At least our cars are garaged while at home, which is usually a bit warmer than the outdoor temps in winter. Typically, if it is 20 outside it might be more like 30 in the garage. She routinely drives about 8 miles to work and then back home. The block heater would be unusable at her workplace, which means that 50% of its use would be negated. Besides, we pay the highest electric rates in the nation, so any possible saving in gasoline would be offset by consumption of electricity, meaning it would be a 'wash'. I've considered a full radiator block, but seeing that I have all the grilles blocked already, I don't want to overdo it. I have a full radiator block on the car that I drive ('89 Galant) but those blocking panels are easily removable.

The weather has been absolutely brutal here recently. Yesterday and today have been about 20 degrees with constant 50 mph winds, which is a horrible wind chill factor. We have all new windows and insulated siding on our home, but those high winds still suck the heat out of a house. :(

I'm aware of that, but I don't know how to teach that to her. The first lesson is to try to lighten the heavy foot.

try an upper grille block and also I'd use a big K&N cone filter in place of the stock airbox, should suck up more engine heat and make the car run a little more efficiently.

Still selling K&N filters, eh? ;)

For a warm air intake, you could save yourself a pile money by doing it yourself with some strategically routed dryer ducting from the stock air box to the warm underhood source of your choosing.

If you read my posts you'll see that I already have all the grilles blocked. ;)

That will be my summer project. (It's too G*%@*# cold right now!). What I hope to do is remove and retain the original air box, and find a smaller air box in a junkyard that I can alter and experiment with.

Shoot use a big 'ol Spectre filter it'd probably work just the same and it's half the price at autozone
Doesn't neccesarily have to be a K&N i was just saying a Cone filter in general

my bad dude didn't really read the whole post

This may be the reason why. It's the electronic control of the transaxle.

The EPA did a study proving that on fuel injected vehicles a clogged air filter will not affect fuel economy, it will only affect horsepower. A K&N won't improve your fuel economy anyway, the DIY warm air intake would be a much better route. Some people prefer filters like Spectre and K&N because they are reusable. However, if you hold them up to the light there are some areas where you can see right through them. Small holes, but still much much larger than the holes you'd find in a standard paper filter. If you plan on keeping the car long term, I'd recommend going with a standard paper filter or an Amsoil Nanofiber Air Filter. They have been proven to filter much better than K&N type filters. This will prevent as much dirt from getting in the cylinders and reduce cylinder wear and help maintain good compression longer.

John,

If you read the entire thread, and particularly my last post, you might realize and understand that the poor city FE has nothing to do with the air filter or anything other than the control of the transmission, meaning the points at which it is programmed to shift. My car is 3 months old with less than 2000 miles on it. It never gets out of 3rd gear until it's over 45 mph.

Installing a different air filter won't help anything.

CLICK HERE

http://i146.photobucket.com/albums/r...eheads_duo.jpg

cone filters.... :rolleyes:

Only driving 8 miles will kill the MPG since the car will not use the some of the sensors till it has warmed up. Also the transmission has two tables one for cold and one for warm in the cold setting it will hold longer before shifting or locking the Torque Converter.

I'm not familiar with the cars ECM but look around for a tuning program like HPTuners (note they do not have support for your car currently but you could contact them). You would not even have to but the programmer as long as you find some one local that has it.

OR you could try finding someone with a TECH2 (dealer often or a great shop) and see if they can scan and lower the 4th shift and TC lock/unlock about 3 MPH.

Good luck.

Thanks. In my case, I drive mostly longer distances on the highway. I could possibly change the temp sensor used for the cold setting slightly. (Not a factor this time of year.) Thanks for the tip about the TECH2. ;-]

Didn't someone in another thread say that these Korean cars are gonna kick ass in MPG?

Dynamic Cylinder Deactivation Could be a Good Solution to This Thread
 

Dynamic Cylinder Deactivation(DCD) Could be a Good Soltion to This Thread.

I installed DCD Controller in my 4-cylinder 1.6L AT vehicle like Chevy Aveo,
and tested it in stop-and-go mode around the city block, yielding some 10%
to 13% fuel savings. DCD reduces the engine displacement as well as the
engine power when you don't need too much power during city-driving mode,
resulting a limited accelaration when you start from stop. Such kind of saving
is even larger than that of driving under steady speed, which is around 5% to
9%. So DCD could be best suitable for city-driving. Trying is believing. I have
made a 4-cylinder engineering sample called DCD-440 for you guys to try.:thumbup:

I'm wondering if your Aveo has DCFO. If so, trying to use engine braking might help your mileage and save you on brake pads and discs.

I'm not sure whether it does or not. I do have a Scan gauge and the only time I've ever seen it read "9999" is during coasting while in gear at highway speeds. Of course, that's when the TC is in lockup and I wouldn't attempt coasting with it in neutral then anyway. It does get 37 MPG when in lockup mode. But the catch is that all our suburban roads have a speed limit of 30 or 40 MPH at most. On a typical Japanese car with an A/T the TC will lockup by 40. But not on the Aveo. Chevy screwed us with the city FE by the way they programmed the tranny. The best we ever get is 24 MPG in all city driving.

Nearly all our driving is done at speeds below 45 MPH, meaning the TC is not in lockup mode. I have never seen the SG read that high at these lower speeds. But I do get better MPG figures by coasting in neutral to a stop sign than I do with leaving it in drive.

I couldn't care less about wear to the brakes. There is literally a stop sign on virtually every corner here and brake life is minimal anyway, due to that unavoidable circumstance.