Quote:
Originally Posted by mans
quoted from a magazine review of the 2011 hyundai elantra:
(quote 
Cruising in sixth gear at around 80 mph with light throttle yields an impressive indicated average fuel economy of around 50 mpg... |
I'm gonna have to call BS on this. It didn't seem right when I read it and it certainly doesn't seem right once I ran a few numbers.
Elantra:
Height - 56.5 in
Width - 69.9 in
Cd - .28
Cda - 6.45
Throwing those numbers into our
aero and RR calculator shows that the engine would have to be running at 42% efficiency to get that mileage!
Quoting wikipedia...
Quote:
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Modern gasoline engines have an maximum thermal efficiency of about 25% to 30% when used to power a car.
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Also, if you compare it to some of the other vehicles in the
speed vs mpg charts posted you'll find that number rediculously optimisitc. It even beats out the Prius which is a more aerodynamic and smaller vehicle and we know the atkinson cycle engine is more efficient than an otto cycle. The cda of the Prius is of 5.83, a solid 10% lower than Elantra. That means their engine has to be 10% + more efficient than the Prius to make up for the aero losses. Call me skeptical, but I don't see that happening.