"Airflow and How it Makes Ponies" Theory, Someone help me out. Options

[FortuneCookie]

Alright guys. I've been looking into intake induction for a while now. I've probably changed out my intake design probably 5 times already just to try to get better gains. I was thinking about getting cold-air intake next since I have a short-ram intake. BUT, as I was thinking, something hit me and it got me questioning really good. As people keep talking about intake, they talk about airflow and how it gives more horsepower by more airflow into the chamber. And ofcourse, more air means more fuel needed. But something else hit me hard. I've changed my intake system a couple times already and all of them felt different in responce. Not majorly but you can tell (it's ur car, you would know). Intake isn't about how much air is going in. Now that I think of it, it's about vacuum! It's not air getting pushed in, it's air getting pulled in. So I questioned to myself, how do I increase the vacuum velocity so that I can get some better gain than what I have now. Well I did some quick research. Apparently, it's all physics. Something that I'm not good at. But my uncle majored in Quantum Physics in college. So I asked him, "Hey, do you know anything about vacuum and velocity for airflow?" And he said, "Yeah. What for?" I said, "I'm trying to figure out how to make air sucked in faster into the my engine without having to spend a big butchet." And he said, "The smaller the pipe, the more vacuum you'll create." And I paused. I said to myself, wait a minute, most of the time, bigger is better when it comes to cars. Like for instance, the bigger the tubing, the more space it would have to channel air to be vacuumed. But it would not create faster vacuum or would it? Not sure but I decided to do more research. And it turns out, that constriction (snake swirl) type tubing actually helps vacuum velocity increase. Not only that but if you have a constriction figure at the both ends or in the middle of a tube, velocity speed increases and also less pressure. I'm stealing these methods from G. B. Venturi who died 1822 as a Italian physicist. http://biyografi.info/kelime/venturi So I figured, how come no ones ever really thought about this? This would actually evolutionize intake tubing design. What do you guys think? Am I onto something?

This post has been edited by FortuneCookie: Aug 15, 2007 - 10:35 AM

[cheeco]

Now that I think of it, it's about vacuum! It's not air getting pushed in, it's air getting pulled in.

its actually the opposite. vacuum is the absence of pressure. the lack of air and pressure in the combustion chamber, during the intake stroke, creates a pressure gradiant that allows atmospheric pressure to force air into the intake system. what you want is the least restrictive intake possible. this will allow the natural air pressure to push the max volume of air into the intake. making more power isnt so much about air speed as it is about the density of the air you have to burn with the proper amount of fuel.

[3s-gte_man]

Now that I think of it, it's about vacuum! It's not air getting pushed in, it's air getting pulled in.

its actually the opposite. vacuum is the absence of pressure. the lack of air and pressure in the combustion chamber, during the intake stroke, creates a pressure gradiant that allows atmospheric pressure to force air into the intake system. what you want is the least restrictive intake possible. this will allow the natural air pressure to push the max volume of air into the intake. making more power isnt so much about air speed as it is about the density of the air you have to burn with the proper amount of fuel.

agreed. its still being pushed in by atmospheric pressure (1 bar...14.7psi)

but what your uncle said about smaller makes more vacuum velocity is true. this what the T-VIS system on first and 2nd gen 3s-ge and 3s-gte's did...closed of half of the intake runner at the side of the head so it had to suck throw a smaller hole at lower rpm under 4000-4200rpm for better torque and response then after it opened the other half! but on the 3s-gt3 open at 4000rpm was a bit late cause the factory turbo was well on full boost by then so most 3s-gte moders get them gutted (the buttiflies in the plate pissed off)...

but yeah for the sack of max power and top rpm bigger is still best!