Turbo Restrictors and Air Cavitation....

[mic*]

Volumetric efficiency of piston motor is crap, compared to a rotoary anyway (should read: compared to something i know sweet FA about, and thus should say nothing about )...

What i would like to know more about is the volumettric efficiency (as per MYNE's definition below) of various 4 stroke piston motors, comparitively.

Gixer,

What sort of CFM figures (convert em to LPM for me first if you like ) does for example a SR20 put out at 6000 rpm say?

Not 6000 LPM be damn sure...

[myne]

Um how?

A rotary, IIRC has 3 chambers per rotor, which is geared UP by necessity so that only 2 chambers are used per revolution of the output shaft.
So, for every revolution the clutch passes to the gearbox, the rotary is breathing 4 times. That's 2x more than a 4cylinder which can only breath twice.

So how are you defining volumetric efficiency?
Should we compare rotaries and 2 stroke 4cylinders? They're on a more even playing feild then.

Last I checked, volumetric efficiency was the measurement of how much of an engine's maximum induction volume was used. I somehow doubt rotaries are THAT much better than a piston motor if they're both graphed over the entire rev range.
And then again, you'd have to compare a stock port vs a stock cam, or you'd again ruin the parity.

[oldcorollas]

lets leave it as the FIA interpretation for high level motorsport.

although a rotary has twice the displaced volume of a piston motor, it is less efficient, so the multiplier is 1.8 instead of 2 (at least for the older lemans races.. is it still the same now?)

[SL666]

A rotary, IIRC has 3 chambers per rotor, which is geared UP by necessity so that only 2 chambers are used per revolution of the output shaft.
So, for every revolution the clutch passes to the gearbox, the rotary is breathing 4 times. That's 2x more than a 4cylinder which can only breath twice.

you were correct, and then incorrect, rotors move at 1/3 crank speed (which is actually the eccentric shaft) so they have 2 power strokes per revolution, same as a 4cyl..

[Ben Wilson]

lets leave it as the FIA interpretation for high level motorsport.

although a rotary has twice the displaced volume of a piston motor, it is less efficient, so the multiplier is 1.8 instead of 2 (at least for the older lemans races.. is it still the same now?)

Sit down, grab a beer and have a read of this thread I wish I'd read it before I sat down and worked it all out for myself....