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Old 05-03-2008 | 04:05 AM
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HaveBlue
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Default RE: Engine Question - need knowledge


ORIGINAL: Briansshop


ORIGINAL: savagecommander

keep it simple. CC's is the volume of the cylinder in cubic centimeters. its just a measure of how much air can be inside the engine at any given time. higher CC's=more air in=more fuel to burn=more power.

Yea,but keeping it simple doesn't answer his question. He asked why the smaller engine was faster.

"its just a measure of how much air can be inside the engine at any given time." The only time a 30.5 will fill it's cylinder with 30.5 ccs of air is if it was to reach 100% volumetric efficiency and that's never going to happen. Yes, a bigger engine will always make more power,as in TORQUE, not HP. You need RPM to make HP [or an S load of torque!] and the longer stroke of the 30.5 is RPM limited.
this is all correct , and long stroke engines develope torque while short stroke develope revs, but all this is dictated by the "timing" of the engine , how the engine is ported is another main factor weather you have a dog of an engine, a torquer, or an rpm engine
timing factors to consider is induction timing,how many degrees of the crank duration the inlet is open, and in the case of two strokes the shape and height of the exhaust port.