[SeanPlunk]

Originally Posted by Vettezuki

Don't laugh too hard. There is a thing called exhaust gas recirculation. It's primarily intended to burn off emissions, but can actually (in well tuned systems built for it), increase HP and MPG.

http://en.wikipedia.org/wiki/Exhaust_gas_recirculation

LOL, I know about EGR, but this is something else entirely. Check out the thread if you get a chance, some of the replies are priceless.