Quote:
Originally Posted by Dimman
http://dictionary.reference.com/browse/progress
#3 down the list.
(I'm bored...)
RX-8 is not the same class of car as the RX-7, that's why Mazda refused to re-use the '7'. Not a valid comparison.
As for engine displacement to power, true. They are not dependent. But to stab a bit at your argument, neither is displacement a pure indicator of economy.
However torque is related to displacement, and increased vehicle mass is often better dealt with a torque increase, in addition to more power.
I would rather drive a 200 hp 2L car that spins to for example 7k rpm, than a 200 hp 1L car that spins to 14k rpm. Making the same power, there is little difference in fuel consumption. Wear and tear is a whole different story...
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It's valid because I say so. lol
Actually it is a pure factor, Displacement is a direct indicator of fuel economy as it is of Torque. You can adjust gearing, cam, and vehicle size. But the displacement determines a large amount of the fuel consumption for cruise and acceleration. Otto cycle ICE is more efficient at greater loads.
Honda has two engines on their Japanese Fit(best example I have) the 1.5liter and the 1.34liter. The 1.34 has been proven to be 20% more fuel efficient in the same car with the same gearbox (CVT 73% efficient).They are not 20% apart in displacement.
Compression ratio also affects torque and fuel economy. DI increases all three.
2liter vs 1liter is a very large difference. What about 2.0liter to a 2.5liter or a 1.8liter to a 1.6liter or even a 2.0liter?