What CFM does a DE draw at 6,000rpm?

[fowljesse]

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.

[tehbrookzorz]

Oh no, here comes the leafblower.

[trick69]

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

[trick69]

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

[Whisper]

Electric turbo device?

Isn't that a supercharger?

[kiwimx3]

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.

[trick69]

a compressor is a compressor call it what you want.

[trick69]

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.

[trick69]

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.

[trick69]

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

[trick69]

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

[Whisper]

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

[trick69]

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.

[Nd4SpdSe]

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...

[trick69]

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