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Thread: 2cy vs 4cy
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Old 04-24-2003 | 07:37 PM
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Sport_Pilot
 
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From: Acworth, GA
Default Re: 2cycle vs 4cycle

Originally posted by DarZeelon
Kinahora,

A single cylinder 2cycle engine has a power stroke every revolution. A 4cycle has one every second revolution.

In theory a 2cycle engine would have twice the potential power of a 4cycle. It doesn't.

You got to read a book about it. In 2 paragraphs in this forum, you will get very partial answers. You can get books about engines in most hobby shops and book stores.

Sincerely,
I don't know of any theory that says a 2 stroke engine has twice the power. The effective displacement of a two stroke is just over 1.5 or so. This is because the ports open well before the piston is at BDC, and this volume is not used except as an induction device. Two stoke engines do indeed have more power at all speeds for the same displacement 4-Stroke. However the larger mufflers make them heavier for the same displacement. This sometimes makes the four stroke a better choice when high speed isn't the primary requirement.