I recently got the AEBS manifold as a late christmas present, and as someone put it;"looks like a troll took a dump inside." I was deburring the little turds inside and was wondering if I should just polish it. Not porting at all, just get it to be nice and smooth inside..Thanks

 

I remember reading on the board somewhere that it should remain "rough".
You may want to do some further investigating before polishing it.
Anyone else have a definate answer?

 

I'm sure if the manifold were to work better polished than AEBS would have done it out of the box, Sven

Do your research though

 

Thats what I wasnt to sure of. I thought it was the head that stays somewhat rough for fuel mixture, but it did't matter what the inside of the intake manifold looks like. Key words "I thought" , therefore I ask...
QUOTE" then AEBS would have done it out of the box".. I doubt it, for $150 you cant expect miracles

 

Ive heard that is should stay "rough" for better fuel atomization. not sure how true that theory is though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98ITR#0020 &raquo;</TD></TR><TR><TD CLASS="quote">I doubt it, for $150 you cant expect miracles </TD></TR></TABLE>
Good point why not try and contact them directly?

 

Should be rough inside. I believe it helps with air flow somehow.. it's been a while since I read about it.

 

should be a little rough inside, outside polishing is okay

 

Wire wheel rough, or 80 grit rough?

 

So where's the info backing up the theories of it supposed to be rough?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRXcellent &raquo;</TD></TR><TR><TD CLASS="quote">So where's the info backing up the theories of it supposed to be rough? </TD></TR></TABLE>

You want there to be some turbulence to aid with fuel atomization.

 

How does turbulence lead to the better fuel atomization though?

 

turbulent air keeps the fuel droplets from sticking together.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRXcellent &raquo;</TD></TR><TR><TD CLASS="quote">How does turbulence lead to the better fuel atomization though? </TD></TR></TABLE>

Its the same concept as the dimples on a golf ball.

 

The fuel does not atomize in the IM. It's ok to polish it inside. It's after the injectors that you want a slightly rough surface.

 

Thanks for the replies, I cleaned up the inside with a wire wheel and put the manifold on last night. I also put the hondata gasket in there as well. Took it out for a test drive last night and the IM definatly stays cold, mind you that it was 15 degrees out also. I was too tired to notice a difference, things are always faster when your tired

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NINJA &raquo;</TD></TR><TR><TD CLASS="quote">I remember reading on the board somewhere that it should remain "rough".
You may want to do some further investigating before polishing it.
Anyone else have a definate answer?</TD></TR></TABLE>

This is correct. It helps with ionizing the air and fuel or something like that.

 

Guys, think for a second! The fuel is not in the intake manifold just the air. I think you are thinking of old Chevys and carburetors with the air and fuel in the intake manifold. Go for maximum flow!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fastom &raquo;</TD></TR><TR><TD CLASS="quote">Guys, think for a second! The fuel is not in the intake manifold just the air. I think you are thinking of old Chevys and carburetors with the air and fuel in the intake manifold. Go for maximum flow!!</TD></TR></TABLE>

for the second time.. is the same concept as the dimples on a golf ball. Its simple physics.


Modified by infinatenexus at 2:59 PM 1/30/2004

 

You need turbulent air BEFORE it reaches the injectors in order to maximize atomization and MAX FLOW after combustion.

 

You want the intake manifold slightly rough, but not because you want turbulent air.

The golfball idea is the right path, but not the right conclusion.

Look at a smooth ball, and the air moving around it. Compaired to a golf ball, and the air moving around it.



The air around the smooth ball, is much more turbluent than the air around the golf ball.

http://www.team-integra.net/se...eID=4

Read Micheal Delaneys excellent article for more on flow quality

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nameless EJ6 &raquo;</TD></TR><TR><TD CLASS="quote">Should be rough inside. I believe it helps with air flow somehow.. it's been a while since I read about it.</TD></TR></TABLE>
not flow, mixture

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by infinatenexus &raquo;</TD></TR><TR><TD CLASS="quote">

for the second time.. is the same concept as the dimples on a golf ball. Its simple physics.


Modified by infinatenexus at 2:59 PM 1/30/2004</TD></TR></TABLE>

Obviously not simple enough - you have it wrong.

Simple explaination:

There are two basic types of airflow over a surface - laminar and non-laminar (turbulant). Laminar airflow is the fastest, but if the surface curves too much (like the outer edge of a golf ball), then the airfolw seperates and becomes very turbulant. This causes drag. There is no exact limit, but a good rule of thumb is a fifteen degree compound curve. Beyond this, you generally get seperation. The golfball is rough so that the air is already turbulant as it flows over it, so there is not the rough seperation when laminar flow breaks up. This results in less total drag on the ball in flight and less heavy turbulance, so it goes farther and straighter.

For a straight surface/pathway like an intake runner, smoother is better.

Atomization is an entirely different issue. Dry air, as in an intake runner or plenum, ahead of the injectors does NOT need a rough surface. Once the air is wet, a SLIGHTLY textured surface (about 80 grit) provides a slower-moving boundry layer that helps prevent the droplets from hitting the walls and precipitating out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Top Ramen &raquo;</TD></TR><TR><TD CLASS="quote">

For a straight surface/pathway like an intake runner, smoother is better.

</TD></TR></TABLE>

thats all fine and dandy except for one thing.. intake runners are not straight.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by infinatenexus &raquo;</TD></TR><TR><TD CLASS="quote">

thats all fine and dandy except for one thing.. intake runners are not straight.</TD></TR></TABLE>

1) They generally have less than a fifteen degree compound curve (unlike a golfball/shpere).

2) Even if you need a 'rough' surface, a 60-80 grit surface is fine for establishing a boundry layer. The original post described the surface as 'looked like a troll took a dump inside.' You may want to leave your intake like that; I certainly don't.

3) Check out the work of P&P'd intake manis from guys like Alaniz or DPR who developed their techniques on a flow bench. They all polish the runners to a pretty smooth finish.