Intake manifolds

[jdbubb at verizon.net (Dan Bubb)]

Uhhh Dude!
They were tested by flowing air through them. Inches of water is simply a way to measure pressure. A column of water exerts a pressure at it's base that is proportional to the height of the column. IIRC ~28" of water equates to roughly 1 psi. Setting up a manometer, which is simply a vertical tube filled with water and applying the manifold pressure generated by the airflow to the base of the column of water, is a relatively easy and accurate way to measure small pressure variations.
As far as the TB's, you can keep making them bigger and bigger and the improvement will be less and less. According to data from TT back in the day, going to the bigger TB was only good for a couple HP IIRC.
Dan


From: "Neptuno" <neptunonc@yahoo.com>
Sent: Tuesday, December 26, 2006 11:02 AM
Subject: Re: Intake manifolds


>I see how part of my question was!!! duh it was tested in H2O, but again does H2O flow like O2? and again the lurking question of the TB's. We all know that some TB's Suck more than others and I mean that in a good way (get your mine out of the gutter people).
>   
>  EL T
> 
> Dan Bubb <jdbubb@verizon.net> wrote:
>  The manifolds were tested without throttle bodies.
> I really have no idea how much better the Fox manifold may be in this area (having never seen the inside of one).
> My A1 manifold was welded up on the back side of the flange so it could be opened up to match the TB without having too abrupt of a transition.
> Dan
> 
> From: "Neptuno" 
> Sent: Tuesday, December 26, 2006 9:44 AM
> Subject: Re: Intake manifolds
> 
> 
>> The question I would ask is which TB was used for the testing? See, I ask that because if the A1 tb was used well then that explains some sort of differtiated gain on the stock A1 manifold, while "restricting" the flow on a fox intake that already would be factory "ported for the larger TB's.
>> 
>> Am I crazy when I say this? correct me if I am wrong, So I guess the point on the post is more about the runners, Correct?
>> 
>> EL T
>> 
>> Dan Bubb wrote:
>> Plus there's the extra added bonus that the old butt dyno is notoriously unreliable mostly cause it doesn't sense acceleration, it senses change in acceleration.
>> So, an engine with a flat smooth torque curve will feel slow and an engine that dramatically "comes on the cam" will feel really fast once it hits the increase in the torque curve.
>> Another thing is engine power vs. driver input. An example here is the bigger throttle body, or in particular a Weber single plate throttle body, vs. the stock TB. Because those TB's allow more air flow for a given pedal movement, they feel faster since the engine has a greater response for given operator input. In reality they only supply an HP or two even on an extensively modified engine.
>> Dan
>> 
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