AIV brings extra air to the cat converter. I doubt that it matters if this air is hot or not. matt ma . 92 SE-R >>> "hlava" <lhlvava at tampabay.rr.com> 06/17/2004 9:05:51 PM >>> >John has an interesting point, here. Does having the aiv breather directly >over the exhaust manifold have a negative effect on its performance or not?