Strange Intake Manifold Design/Thought/Idea
 

I don't know what made me think about it, and the idea probably sucks, as I am no genius when it comes to physics or fluid dynamics or whatever, but what about an intake manifold designed like a long tube header, but equal length(basically like an equal length turbo manifold but with a TB flange faced the right direction)? Instead of a chamber and runners, how would it respond to having equal length runners and a merge shortly before the throttle body with a collector.. It seems like this would have pretty good distribution of intake, but I dunno how it would affect the powerband(probably shift it up)?

Has anyone tried this, I think some of you welders out there should fab up something like this just to give it a try and see how it would work..

O0

Re: Strange Intake Manifold Design/Thought/Idea
 

like reverse 4-1 header with a tb on the end. my friend thought about building something like that. but without a plenum he wasn't sure if equal air would go to each cylinder's. like would the 1-4 evenly split the incoming air?

im sure this will be a good discussion tho

Re: Strange Intake Manifold Design/Thought/Idea
 

There is a plunum becasue when your cylinder gets to the intake stroke you want a reserve of air ready to be sucked in. If you dont have this researve you can imagine the cylinder going down and not enogh volume to fill it. This would cause a drop in VE and therefor power.

I know someone is goint to say, but its turboed...air gets pushed instead of sucked.

Air moves because of PRESSURE DIFFERENCE. When the cylinder moves down, volume is increased so it creates a lower pressure then outside the cylinder so aire flows from high P to low P. Same holds true of NA ans FI. On a turbo you have 14.7pisa+boost on the manifold, on NA you have 14.7psia. On the cylinder side you have vacuum-residual exhaust.

Some mazdas have sidewinder type intake manifold, check it out when you go to the yard

Re: Strange Intake Manifold Design/Thought/Idea
 

Hes on the right track, but anothering thing that the plenum does is this. It acts as a spring, so to speek, when the air flows down the intake manifold towards the valve on the intake stroke, the higher pressure in the plenum forces air into the low pressure area created by the downward draw of the piston, since air is like any other object and it doesnt want to stop once its in motion when the valve closes it bounces off. The plenum is there with a flat non-resonant surface that causes the air pulses to bounce back towards the valve. The proble with that is it only works in a narrow rpm, so in order to build a good manifold you need a dyno and alot of math equatiions. NOw if you had the setup you all are talking about the air would just bounce off the valve and than go back down the intake tract, wich isnt good and would probly cause some compressor surge, or at least slow the air comeing in.




Sean

Re: Strange Intake Manifold Design/Thought/Idea
 

i too thought of something like this but more for race apps. same idea as the log mani but you make a tb flange stick straight up trew the hood and slap a filter on it. in my head it looks kinda goofy but no more than the guys with one headlight and a filter in the empty hole

Re: Strange Intake Manifold Design/Thought/Idea
 

Well then what about ITB's? Obviously there is no plenum or the type of air interaction going on here that you are describing..

I think that it would not be a great idea for a NA car, or a stockish street car.. but for FI apps with high hp, I think this might be somethin to try.. there is no way noone has tried something like this!

dammit somebody weld something up like this I just want to see the results hehe..

Re: Strange Intake Manifold Design/Thought/Idea
 

what do you think the velocity stacks are for on itbs? the trumpet sort of forms an 'air wall' so to speak that acts like a plenum.


sean

Re: Strange Intake Manifold Design/Thought/Idea
 

if a 4" long open ended trumpet can hold air why wouldnt the 1>4 design do the same??

Re: Strange Intake Manifold Design/Thought/Idea
 

an ITB has the largest plunum of them all, think about, it can use air from the whole engine bay.

The Helmholtz Resonator idea I was originally talkiing about is air acting like a resonating mass and VE peak tuning for that. For more info google it. Its a 2nd order diff equation to solve but there are some quick and dirty aproximations that you can do in excel.

The log manifold idea is exactly like the new HF design or even the EF DX/STD design. Typically this is for low end/cost only which means it sucks for the torquless small displacement engine.

Think about throttle body spacers for V8 domestics, basically your adding plunum volume and it helps out performance.

Another thing it does I didnt mention before, when a fluid has a high velocity the pessure drops (this is why wings make lift). The volume of a plumum alows a high pressure charge of air to be ready in reserve when its needed. Thats why sizing rules usually are just a multiple of displacement.

Re: Strange Intake Manifold Design/Thought/Idea
 

all these theories are great, but I still think someone should it and find out :D

EDIT: nm, found this,

http://honda-tech.com/zerothread?id=501884

it has already been done and it obviously works.. :D