Originally Posted by 1MOREMOD
i made my own using apex gt4 ducts and bought rest of my parts from summit. ended up doing 3 inch the whole way which was a mistake due to excessive rubbing. works fine for a non street car but turning radius is greatly reduced.
Does the 3" fit through the undertray piece? I'm thinking of doing what Richbot mentions below.
Originally Posted by Richbot
Some on here have seen big improvements with just a 2.5 or 3" hose routed to the fender liner the way just about all BMW's are set up, except on our inexplicably ductless cars. You don't necessarily have to go with backing plates to get most of the benefit of ducting when you're starting with zip for cooling (like we have from the factory for some reason). For a street car that's where I'd stop, coupled with a better pad, if I wanted to stay with the stock brakes anyway, but that Stoptech front 355 kit is so reasonably priced relative to a $800 stock front brake job, kinda makes it hard to ignore the opportunity to upgrade unless you really just want to stay stock or are really sticking to a budget
I'm thinking this is good enough paired with a BBK. What did you use on the back side of the undertray to secure the duct?
It just amazes me we have no ducts at all. E46 had then blocked off, but at least they were there.