I just really dont see the point of these things. I am sure they serve a purpose, I just haven't found one yet.
The purpose is to reduce that point of detonation so you can push everything further. The PCV vapors reduce the octane rating of the A/F mixture entering the combustion chamber.
I was running 30 PSI of boost while using E85 on a daily driver and didn't need a catch can SO????
Not necessary in my book.
You need a new book. And besides, E85 has such a high effective octane rating that you might as well just call it racing fuel- if you detonate on THAT stuff, you're trying to run it in a diesel. :-p
Look, there are two different reasons to think about an oil trap in the PCV system. THIS thread is about a PCV system that sucks in more oil mist than it should due to short/small hoses and insufficent baffling above the camshafts in the valve cover, and the main problem is that oil consumption increases due to the volume of mist being sucked in adding up over the months. What you don't want is a race-type "catch and empty" can, you want a "catch and release" trap that will separate the clean oil mist from the PCV air and then return it to the crankcase when the engine shuts down or vacuum drops significantly. A coil of fat PCV hose will work pretty well for that, or an in-line screen type fuel filter- anything that causes an area of slow airflow where the oil mist can fall out and collect.
The OTHER reason for a catch can is to prevent octane decrease due to oil in the air flow. And your thinking is backwards- its not much benefit to boosted engines because their PCV system shuts down under boost anyway. Its a bigger help to high-compression normally-aspirated engines, and is easily verified by comparing timing pull-back due to the knock sensor with and without a catch can. Some cars benefit more than others.
And the final benefit is that the intake tract stays a heck of a lot cleaner with less PCV liquid crud passing through it all the time.