I was just reading through my FSM looking at emission control stuff (trying to pass emissions test) and I got a question. The AIV opens when the pressure in the exhaust manifold is less then atmospheric presure, drawing in air from the intake. Negative pressure in the exhaust manifold is good, as it helps to pull exhaust out of the cylinder (scavenging?), right? If so, doesnt the AIV remove any benifits of this negative pressure in the exhaust manifold, and therefor removing it would help out a bit? Is this right, or am I way off?

dunno, but you won't find one under my hood:D

I don't really know either, but I had mine removed when my header was installed. I figure it wouldn't hurt if I removed it.

I would assume it would hurt emissions to take it off. I think by adding air to the exhaust, it helps the cat do its job by giving it o2 to stick on the co to convert it to co2.

PAIR Valve (http://www.se-r.net/header_exhaust/pair_valve.html)

Chris

Supposedly you get no gain, but I as well took mine off along time ago. Mine actually messed up(reed valves) so instead of fixing it I took it off.