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I asked on another forum, and got this answer:
theoretical maximum is 2.5 L per 2 revolutions. (4 stroke engine)

6000/2*2.5=7500L
This makes sense, but how do I convert it to CFM?
I need to know for my top secret new forced induction device.

Oh no, here comes the leafblower.

here's the formula you need
CFM Required = CID x RPM / 1728 / 2 x VE (for fuel injection your volumetric efficiency or VE is 1)

Roughly 260 cfm give or take a a cfm or 2

just so you know they sell an electric turbo device, their supposed to be capable of 2-3 psi boost fyi It doesn't get any better unless you boost properly. you'll never get above atmospheric pressure it's not just about cfm

Electric turbo device?

Isn't that a supercharger?

Im sorry to say your maths are wrong, would be correct if it was just a engine with no heads
on it and the pistons going up and down displacing air.

a compressor is a compressor call it what you want.

alright you want to get technical I will need the cam specs on the intake valve sizes and the flow rates of the heads. But since none of us know this I can tell you without a doubt the best ball park figure is 260 cfm without a doubt. the math equation I gave has been used for years it designed for sizing carbs to engines I've used it for years. And since I'm a mechanic I would say It is accurate. If you want to argue more I suggest you google search how to find this formula. And if your so smart lets here your awnser.

what the hell do you think an engine is, It's a freakin air pump. It draws in air and displaces air oh sorry hot exaust gasses. volumetric efficiency was acct. for. Just stop and think a ford 302 (built lots) requires a 550cfm carb 5.0L a 2.5L will more than likely require about half. That equasion is one I learned in school.

for the record only one intake stroke per cycle. tdc. intake. comp. ignition, exaust.tdc

kiwimx3 wrote:Im sorry to say your maths are wrong, would be correct if it was just a engine with no heads
on it and the pistons going up and down displacing air.

so is it less or more I guess I should stop working on cars then

LOL. Can't you edit your posts to add information, instead of making new ones?

I'm pretty drunk but the question was how much cfm does a 2.5l draw. Maybe I was wrong assuming that v.e. is 100% but I'll bet it's close with the way our Vris system works these little engines get all the air in they can before that valve shuts. And I think for shure they fill there cylinders. keeping in mind atmospheric pressure is the usual 14.7. but lets say V.E. is only 85% thats still 220cfm which I highly doubt(not exactly a smogger motor) realy what this is about is someone wants to boost a car some weird way there's only two ways blower or a turbo. you can't hook up a bathroom fan just because it says 600cfm the fan will stop turning.

Whisper wrote:Electric turbo device?

Isn't that a supercharger?

No. A supercharger is a compressor driven from the motor with a belt. A turbo is a compressor spun by the exhaust gases. An electric turbo/supercharger is just a waste of money, lol.

Indeed trick has it right. CFM is just now much air it moves, but it's not about moving air, it's about compressing it. You can have a fan that moves 10'000cfm, but if it can't compress the air, it won't do anything...

Nd4SpdSe wrote:

Whisper wrote:Electric turbo device?

Isn't that a supercharger?

No. A supercharger is a compressor driven from the motor with a belt. A turbo is a compressor spun by the exhaust gases. An electric turbo/supercharger is just a waste of money, lol.

Indeed trick has it right. CFM is just now much air it moves, but it's not about moving air, it's about compressing it. You can have a fan that moves 10'000cfm, but if it can't compress the air, it won't do anything...

FINALLY SOMEONE WHO KNOWS WHAT THEIR TALKING ABOUT THANX. there still both compressors