Haha, I know what you guys mean with the sound complaints. I had a T-trim and Tial Q BOV on my Cobra and everyone at work was like 'why does your car sound like a 747 when you drive in?' Could definitely street sweep a road with the BOV too, I think the air coming out of that thing at idle was more than the aux fan pushed when it was on low.
There is a big difference in the amount of air being released by a BOV between an Evo and a blown V8. Just think, an Evo has a relatively small turbo forcing air through maybe 2.5" piping, relatively small I/C and into 2.0L of engine. A blown Cobra has a huge supercharger forcing air into 2.5-3" piping, through a big intercooler, and into 4.6L or even 5.0L of V8. I'd want a much bigger BOV on the V8.
I had the Vortech Mondo on my car and it didn't seem to be working right, so I bought the Tial Q 50mm BOV instead. Same BOV the pros use, including a pair of them on just about any TT Viper, Ford GT and Gallardo you'll see. The thing is LOUD too, which I usually didn't mind. Cruising down the road at highway speed wasn't bad, but drop it in 3rd at 65 mph and you'll destroy the ears of the person in the car next to you. Ask my friends :-D
Anyway, 20+psi has my old Cobra, ask him about it. I'd bet it'll work just fine even with his new YSi setup.
Yeah, I do realize that the EVO will flow alot less. I was just saying that I remember my buddy sayin somehing about doing that mod to the BOV.
Also, at least for now and into the near future I will be staying below 10psi. Right now I'm at 6 and the BOV seams to be doing fine. It does whistle just cruising around tho, and that is annoying but usually just using the next gear quiets it down a bit. Once I go more I will probably switch to the Vortech Race BOV or something bigger.