

Chevrolet Cruze Eco
Cruze Eco gets better fuel economy than many popular hybrids







The Cruze Eco will hit dealers in January at $18,895.

Comments     Threshold


Why the big gap in highway mpg?
By corduroygt on 11/12/2010 10:17:45 AM , Rating: 2
42 for manual and 37 for auto? With the same gearing and a lockup converter, hwy mpg should be the same, or very close.

RE: Why the big gap in highway mpg?
By bobsmith1492 on 11/12/2010 10:42:40 AM , Rating: 2
Perhaps there's more internal friction in the automatic? Maybe it weighs more, too? Probably the gear ratios are different, at least.

RE: Why the big gap in highway mpg?
By Kurz on 11/12/2010 2:49:38 PM , Rating: 2
Weight isn't the issue (Less than 30 pounds for compact cars).

The problem is the damn design of an automatic is whats so bad. Its so complicated.

By Pneumothorax on 11/12/2010 10:55:11 AM , Rating: 2
The automatic engine probably has a slightly different tune on the air/fuel ratios and turbo to increase mid-range torque & drivability.

RE: Why the big gap in highway mpg?
By DerekZ06 on 11/12/2010 1:18:41 PM , Rating: 2
An auto has much more rotating mass and parts which create friction. Also, even with lockup, the torque converter still has trans fluid in it which is still flowing the same way it would be if it was unlocked. It's just that when it is unlocked it can't run 1:1 with the engine so the engine always has more RPM's on it and the fluid is flowing faster because of it. Which all increases friction.

RE: Why the big gap in highway mpg?
By Tabinium on 11/12/2010 1:37:03 PM , Rating: 3
In the past this was true, but there are several vehicles on the road now with higher (Chevy Camaro) or equal (Honda Accord) ratings for automatics. I think manufacturers are just spending more time on Autos due to how much better they sell...but that's just my own speculation.

RE: Why the big gap in highway mpg?
By Keeir on 11/12/2010 5:33:02 PM , Rating: 2
Hello Tabinium

Sadly, most manual cars get worse HWY MPG than they should due to poor final gearing ratio.

City MPG is mainly due to shifting losses. The EPA is not required to test a manual on the EPA City cycle the most efficient way possible. Instead, the EPA forces the car to meet certain speed and acceleration targets... on top of this, the Auto makers don't have the incentive to game the EPA to the same extent with ECU tricks.

Manual driven at steady state will always be several percentage points more efficient than a automatic. But a manual driven by a moron (or someone who doesn't care I guess) will be less efficient than an automatic driven by a moron. So I guess the EPA is showing reality as reflected by a typical US car buyer...

