Exactly, what is the point of having cutouts directly after the collectors??? There are a few things to consider. At WOT, you fall into a direct multiplier function of fueling, where fuel is determined by a preset calculation in your PCM configuration. Not like when you are cruising around where your fueling is constantly adjusting based on EFI monitoring systems. So at WOT, it really won't hurt much of anything, supposing the tune is correct, and not taking into account the transfer or closed loop trimming (which can happen, but we won't go into that for thsi discussion).

For closed loop fueling (normal driving), having a cutout behind the collector isn't quite as bad as open collector since you are still adding length to the exhaust conduit and thus creating more stable and representative pressure/heat in the exhaust stream for your system to sample. This is why you don't necessarily see the same effects. But any good scan session will show a pretty clear difference b/w running exhaust out the back, vs dumping it closer to the engine.

There is a point where dumping may not contaminate the exhaust metering, and you can guess that the further away the better. Obviously there is a balance though, we can't just have a 30 ft pipe and expect that to be optimal for power either. Dumping does evac more cfms for high rpm power production, that's been proven, and too long or tight of an exhaust can squelch power production from lack of excavation. A cutout at the end of the Y is definitely far enough away to not bother closed loop fueling and get you the power you seek. Cutouts after the collector, in my opinion, should be placed as far back down the Y-pipe as possible to avoid any unwanted ill effects.

With all that said, since most of us run stock cubed motors anyway, THERE'S NO NEED TO BE DUMPING ANYWAY! A well designed 3" exhaust out the back can more than accomodate even most big cube LS setups. So the original question, "What is the point of cutouts?" Your answer: Noise, and sometimes shittier gas mileage...

 

I drove my LT1 open header, its loud as **** and your constantly checking for cops, because unless you idle it that thing is going to be loud as hell.