Originally Posted by Evil Aviator

The required boost increase is mostly due to the higher pressure drop, not so much the size. The pressure drop is dependant on the construction of the intercooler, and you pretty much get what you pay for. The plumbing (mostly the bends) will also affect the pressure drop, but you don't have many choices on how to construct the plumbing given the underhood layout and space restrictions.

The increased lag is due to two factors:
1. The larger volume (as you have already figured out)
2. The extra spool time required for the turbo to make up that extra 2-3psi.


Gotta love the cold sink factor of a massive intercooler.


The air will take the path of least resistance. Once pressure builds up at the bottom of the core, more air will flow through the rest of the core. Besides, you can construct the end tanks with baffles if you are really concerned about the air getting through the entire height of the core. A taller core has more internal flow area, which will reduce pressure drop. A larger core also contributes to cold sink, which helps reduce the spikes as mentioned by mperformance.