Sheet Metal Intake Manifolds

[Smokeshow]

When designing a manifold. Minus the countless possible hours of R&D. Is there a specific formula that you use when trying to design one. I have read and read and read. Is it really that detailed? Or are there some short cuts? Details like, Runner length, Runner I.D./O.D, Plenum Volume, CFM Velocity, Volumetric Efficiency, Displacement, Desired Powerband, N/a or F/I... etc.. etc... Just curious...

[Aerometalworker]

When designing a manifold. Minus the countless possible hours of R&D. Is there a specific formula that you use when trying to design one. I have read and read and read. Is it really that detailed? Or are there some short cuts? Details like, Runner length, Runner I.D./O.D, Plenum Volume, CFM Velocity, Volumetric Efficiency, Displacement, Desired Powerband, N/a or F/I... etc.. etc... Just curious...

Yes....there is that much to it. You cant just look at the manifold as a seperate unit, it is part of an entire system that includes valve lift profiles, combustion, etc etc.. There are lots of good texts on the subject that will get you 80% of the way there, the other 20% comes from experience.

[Smokeshow]

I have increased my studies as of late, on this topic. I have noticed some use trumpets/flares on the ends of tubing/intake runners. While others don't. Some weld the top of runners and leave them. Some weld the top of runners and machine them. From my reading, I have gathered that you are not supposed to have the runners side flush with the bottom of the intake. I am wondering if this is due to personal preferrence or actual knowledge of engines and air flow?

[H80N]

There are some guys that have brought sheet metal manifolds to an artform..

John Marcella is one of them... his work is just beautiful..

Here are some videos...

http://www.youtube.com/watch?v=RGPgsXwgQkQ

http://www.youtube.com/watch?v=Db6BVMANvW0

Here is the link to his website... lots of pics

http://marcellamanifolds.net/images/Images.html

(And yes I realize it is an old thread..and that some have seen this work.. but it is so nice... it may serve as an example of the art...)

[TTNickSoCal]

I have increased my studies as of late, on this topic. I have noticed some use trumpets/flares on the ends of tubing/intake runners. While others don't. Some weld the top of runners and leave them. Some weld the top of runners and machine them. From my reading, I have gathered that you are not supposed to have the runners side flush with the bottom of the intake. I am wondering if this is due to personal preferrence or actual knowledge of engines and air flow?

The trumpets you're referring to are called velocity stacks they improve the physics of the air flow thru the runner. They typically will boost the performance of the manifold.

http://en.m.wikipedia.org/wiki/Velocity_stack