intake manifold tech

[twilightprotege]

hey

technical quesion....i'm sure there is an answer, i just hope somebody knows it.

what is the mathematical formula to calculate intake manifold tube diameters/lengths etc to get xxx amount of power etc

like i said i'm sure there is a formula, there has to be. hope someone knows it!

later

 

[Little Beavis]

Wow, man, that is such a loaded question. . .why don't I just explain women to you instead?

You're looking for an equation that says L = xxx and D = yyy, but what about intake pulses, tuning for resonance, flow past the throttle body, flow through each runner, flow through the valves, not to mention: fuel atomization, vaporiztion, and transport phenomena, and emission controls such as EGR. Oh for the love of Mazda, my head is hurting. . .

The closest thing I can tell you is that if you figure out how much horsepower you "want" and determine the amount of air you need to "inject" to get this, you will know the relationship you need for the intake. Typical intake design is such that the volume of air pulled into a cylinder each cycle should be such that it equal to the volume of the intake runner for that cylinder. Thus your L*D^2/4*pi, where L = the flow path from the throttle plate to the intake valve and D is the diameter. . .

From that you would need to look at your air velocities since a small D would result in a faster flow, which in turn shoud be compared to the Reynolds number and so on. . .

Man, this sucks. . .I should delete this post, but I'm not going to. . .hope it helps or makes sense. . .you don't really want to see any of the equations that I found. . .

GOOD NIGHT! (I can't continue after that. . .)

 

[twilightprotege]

cool. that's a great start....i know it's a very very complicated formula to work out that XYZ is the best intake manifold for my app...i know the formula for calculating the best turbo for an application (6 formulas i think)....so thanks!

 

[Togan]

Gurlfriend=Money+Time+Patience+Car

thats the formula all u need to know lol

jk well just use L*D^2/4*pi, what beavis said...

 

[twilightprotege]

LOL....or gurlfriend+money+time+patience+car=car accident

 

[Togan]

LOL....or gurlfriend+money+time+patience+car=car accident

urrrrrrr right buddy everyones got their own formula so theres no wrong or right

u might even consider the following:

gurlfriend+money+time+patience+car+car accident = ****** up life
(lol)

 

[YuYuRena]

Try to use this program.

http://www.mazdamp3.com/vbb225/showthread.php?s=&threadid=28077

It might offer you some help. Or go to the library and look up internal combustion engine.

The basic concept for intake manifold is outline just like beavis said.

 

[Little Beavis]

That link is cool, but I do want to throw some caution that as soon as you have multiple cylinders (which we do last time I checked except some of us only have three. . . (flame), whoops), but anyway, it will change a lot of stuff with regards to the intake manifold.

Man, the equations are SO nasty for this. There are some filling equations and such that help, but you probably need to go buy books and become the expert yourself. I only know enough to be dangerous.

 

[twilightprotege]

cool, thanks for that link!

 

[YuYuRena]

Well i know about that it only simulates 1 cylinder, but I'm talking about a starting point. The most basic fact are there, if you consider each cylinder acts by themselves with the other cylinders affecting the "ambient" conditions, such as the intake and exhaust. You can model that into the engine if you account for say exhaust expansion pluse returning to your exhaust port in your cycle analysis. Hope this clears it up.