Quote:
Originally Posted by steveX
If a rx7 truly pose a 1.3 liter, why does it burn almost the same amount of air/fuel has the 3.8?. and no way close to the Toyota 1.8 liter.
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For one thing, nobody ever said fuel economy was based on displacement alone, in fact the two are mutually exclusive. For example I have a 2.4L I4 in my Topaz and I'm lucky if that thing gets 20mpg, where as in my 3.8 Monte Carlo I regularily see low 20's and I have a heavy foot. Also, how many other 1.3L engines do you see pushing out 200+hp, or in other words the same power output as a stock GM 3.8? That power has to come from somewhere, it sure isn't in the air. Also the style of the combustion chamber and how it functions plays a huge part in fuel economy as well. For example a piston engine on the intake stroke is tuned to swirl the air/fuel mixture as it enters into the combustion chamber, allowing for a better mix and thus a cleaner burn. A wankle on the other hand given how it functions isn't able to get that swirling effect and thus requires more fuel to make up for it, a natural inefficiency of the engine itself. Every engine has it's faults, but people who buy rotary-powered cars don't exactly buy them for their economy in the first place so in the end it doesn't even matter.