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Old 04-10-2012, 06:59 AM   #215
ZDan
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Quote:
Originally Posted by DSR2409 View Post
How is 238 hp from a 1.3L engine inefficient?
It's inefficient in that it burns a LOT more fuel relative to its output vs. piston engines. And judging from measured rwhp and acceleration times, it's really more like 220hp.

Quote:
If you were to get a piston engine that displaced 1.3L to that hp number, it would require forced induction, and burn way more fuel...probably even more than a rotary.
A turbo'd 1.3 liter would get better fuel economy than an n/a 2.0 liter with the same peak power, and would get WAY better fuel economy than a 1.3 rotary.

There's a reason we're seeing a shift to smaller-displacement turbos as CAFE is being jacked up again. Better fuel economy for a given power output.


Regarding rotary displacement equivalency, although rotaries aspirate their full displacement every crank rev and 4-stroke piston engines only aspirate half their displacement per crank rev, rotaries don't make twice the power per displacement. More like 1.5x (applies to 2-strokes as well).

I'd sooner argue for calling a 2.0 liter 4-stroke a 1.0 liter than to call the rotary a 2.6, which I think is kinda ridiculous.
I think that the way they are rated for displacement (1.3 liters) is appropriate. They do give a lot more power/displacement than 4-stroke piston engines.
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