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Old 07-05-2014, 06:11 PM   #34 (permalink)
ERTW
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Join Date: Jan 2012
Location: Toronto
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Bu - '08 Chevrolet Malibu LS
90 day: 32.29 mpg (US)
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Quote:
Originally Posted by ecomodded View Post
I 'll paint a picture for you

Say you as in You are driving in your peak volume efficiency all day long.

But me I'll be cruising at 1000rpm all day, who do you think would consume the largest amount of fuel ?
How about we dispense with pictures and use numbers and actual logic?

Using the same car, you may use less fuel, and you'd be much slower. But that nowhere near what I'm saying. I say "efficiency", you understand "performance". ?! RPM does NOT automatically mean less fuel. It's about the load on a vehicle (drag and friction) and how efficiently the engine produces the power to balance the load. Newton's second law.

Haven't you ever compared highway consumption of a mid sized car with the four and six cylinder engines? The Malibu 2.4 gets 33 mpg highway vs the 3.6 26. That's 27% better. It cruises at a higher rpm. That is typical. Still feel I'm wrong?

There's an optimum engine size for a given car, at a given speed, which minimises consumption. Eg The 2014 Stingray is best at 5.7L per GM's SAE paper. The 6.2 was still marginally better than the 5.3 because it ran in V4 mode longer.

To take it a step further, design a smaller engine with the same power at part throttle, and lower pumping loss, and you get better economy.

This is the rationale to OEM downsizing engines. It's not "my logic". I'm done arguing.
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Last edited by ERTW; 07-05-2014 at 06:26 PM..
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