The Dark Side of Will wrote:anti-surge recirculation?
Bingo...You can see where another ring was actually picked onto the top of the recirculation passages like this:
http://img.photobucket.com/albums/v87/F ... o/7f_1.jpg
You can see the gap in between the ring and the top of the passages...I haven't found anything regarding the advantages between leaving it in, and taking it out like in your friend's turbo...The 4" inlet is going to be a major PITA for me too.
Although, the way I'm leaning seems to be contrary to many turbo retailer's move of taking the ring off. In my opinion, it seems that introducing the anti-surge ports directly to incoming intake air would impede proper flow through the remaining length of the compressor blades, as well as decrease effectiveness of the anti-surge inlet by removing proper flow past the gap between the ring and the inlet. I think they take it out to make the intake appear much larger.
But that's really all a guess. :thumbleft:
Nate
Indy DOHC Turbo SD4.....someday.
Oh, and f*ck the envelope. (RFT Insurgent)