Prius Eco 58 MPG vs Prius 54 MPG - What's the difference?

Are the vanes universal?

I found a complete lower bumper block gave a 3-4% improvement in highway MPG. I had mentioned it at Detriot to the chief engineer.

Bob Wilson

 

The press release reads, "A new Eco grade model is expecting ratings of 58 MPG city / 53 MPG highway / 56 MPG combined thanks to lighter weight and further optimized aerodynamics."

I'd bet more has been done (aerodynamically) than just removing the rear wiper. Toyota claims a reduction for the Corolla LE Eco of Cd .02 (from .30 to .28) compared to the regular LE, even though the two models look the same, and improvement of +1mpg city/+4mpg highway/+3mpg combined with no improvement in weight. Aerodynamics play a role any time a bluff body moves through air, and reducing aerodynamic drag will improve efficiency at any speed--the effect becomes more pronounced at higher speeds.

 

it is weight that helps with the city... tires help with everything and aero at highway speeds.

There is no power difference or anything like that, which is obviously from all the materials.

 

So Ken1784's post number 67, regarding the ECO's lower weight putting it in a more favourable fuel economy testing class, is not applicable in North America? Has that been put to bed?

Gen 4 Staff Manual (In Japanese) =/ Specs/Design/Other Info | Page 4 | PriusChat

 

will these numbers hold up on the epa test?

 

I don't understand the mpg difference between the regular and Eco trim either. It seems weird.

Are the tires really the same size and height/width ratio on the Eco as the other 15" wheels. Different tire design?

 

It is ~8% (56/52). On JC08 it is also 8% (40 km/l vs. 37).
What really seems weird to me is the low non Eco estimates on EPA! only 4% improvement from Gen 3 (JC08 and NEDC show considerably higher improvements.

 

It's not ~8%. The independent variable needs to be in the nominator.

56mpg = 4.2L/100km
52mpg = 4.5L/100km

(4.5-4.2)/4.5 = 6.7%

 

Yes. My vague impression is that JC08 and NEDC are slower speed and steadier whereas EPA cycles speed up and slow down more and have higher speed cycles.

One obvious possibility is that the new powertrain has been especially optimized for certain speed ranges and steady speeds (mild torque) compared to gen 3.

 

It is a surprise to me.
Unlike Gen 3 (non Eco), Aqua achieved artificially high score on JC08 due to their 'weight classes' system. If you compare it to Gen 3 Eco in Japan (also artificially high score of 32.6 km/l) you see about the same 'barely on par'.
Here we are talking about two cars with almost the same weight and same 'weight class' on JC08.

Wrong mathematics.