Whassup ya'll, I had a B20B in my car for a while that I spun a bearing in so I just said expletive it and bought another one. This new one I have is a 2000 JDM B20B this the USDM B20Z Specs. PHK Maniflold, knock sensor, silver chamber on top of the manifold. My question is should I use that box on top of the manifold or not. If not I can just put the P75 LS style manifold from my old B20 on cause I know that heard that whenever you take off that box there are two holes on top of the manifold, so that would be the reason for putting on the old one.

Let me know the pros and cons about that silver box on the top of high compression B20s.

This is what is said about it
The idea is that the "resonator" chamber works like long runners and a larger plenum when the pressure waves travel back up the intake from the ports. Compared to the giraffe manifold (B20b) this gives good top end and good midrange grunt. This probably fills in the low-midrange hole we see on a B20 using an LS manifold (see dyno). There is probably a performance draw back to this system in the upper 6k+ rpm range, otherwise wouldn't see this box on the ITR manifold also?

This is a pic of one with the box



This is it with out the box

 

you can use either the b20z intake (w/ box) or the ls intake...doesnt matter
your call entirely

 

yeah but I would like to know whats better because I know how hard it is to change an intake manifold when the engine is in the car so I'm trying to find out from a good tech who knows for sure what is better before it even goes in the car. Thanks though