Stock plenum

[Boogieman142]

I know this has been a debate for quite some time but what is that divider in there really for, to split the air up to each half of the plenum. And if i remove the top grid will it be too thin and start flexing? I was thinking if i fill in inbetween all of that grid then wouldn't that work just as good while still retaining its strength? I plan on doing a very radical porting of the neck also.

[c2xejk]

I removed the dividers and grid and have had zero problems. My van routinely idles at 21-22 inches and I have done more than a little engine braking...

[Boogieman142]

ok, works for me. I may have just had a change of plans. that mitsu intake i have lying around just may get put to use.

[mwinkle353]

lol, that was quick.

I can't help but to believe I had something to do with that.

[Boogieman142]

yes you may have.....

[Avenger]

The divider is to prevent one cylinder from starving others. When the valve opens, there is obviously a vacuum that pulls the air down the runner. That creates airflow in the plenum towards that runner, and away from the others. The divider also breaks up the incoming air flow and prevents it from "stacking".
As far as how much of the grid you can remove, I milled mine smooth, and had no problems. Ace took out slightly more material, and the top of his plenum was VISIBLY flexing. Not anything to worry about, but it was neat to see!

[Ondonti]

dont remove the ridges on the top of the plenum (the outside) I think doing that combined with porting the inside is what contributes to the intake manifold flexing. Mine has a pretty aggressive port and I dont have flexing problems.

[Avenger]

Yeah, what Brent said. I forgot to mention Ace had smoothed the outside of the plenum as well.

[ross]

mine is completely bare inside and i have no problems what so ever and i also put on the 52mm throttle body

[onecrazyphucker]

I have never noticed any flexing. Mine was heavily ported in the inside, but I never touched the outside.