Exhaust collector theoretical question

I have been wondering, and have asked a few exhaust companies this question, with dumbfounded answers...uh I never thought about it that way. The collector being a merge or standard as critical with an exhaust system attached to the collector? Does the engine even see the collector with the exhaust attached? Are step headers seen the same way by the engine with exhaust system attached? As opposed to being uncapped? Any thoughts?


David

im not an expert, but i would guess that it still "sees" the collector because it is the place where all 4 primaries meet, and is larger than their invididual sizes, and this would not be changed regardless of how much more pipe (ie the exhaust) is attached to the end of it.

Any more ideas? No one ever thought about it?


David