4.0 air intake tube on 2.5?

[SSTJ]

They actually worked together to control intake pulsation. While some would argue they may help with power they are primarily for noise abatement.

Thanks. So why does the 2.5 need this while the 4.0 doesn't? Also curious what's going on in that big box. Is it just an expansion chamber or what would I find if I opened it up?

Edit: @Blackjack, I see you answered this a year ago here, where you said that the larger box was also a resonator for noise reduction. So now I wonder why the 2.5 has all this noise reduction and the 4.0 doesn't.

Edit: Wondering if @Jerry Bransford has heard anything in his conversations with those involved in the original design.

 

[SSTJ]

Thanks. So why does the 2.5 need this while the 4.0 doesn't? Also curious what's going on in that big box. Is it just an expansion chamber or what would I find if I opened it up?

Edit: @Blackjack, I see you answered this a year ago here, where you said that the larger box was also a resonator for noise reduction. So now I wonder why the 2.5 has all this noise reduction and the 4.0 doesn't.

Edit: Wondering if @Jerry Bransford has heard anything in his conversations with those involved in the original design.

I was wondering this again today.