It pumps air to help with pollution. It helps cylinders burn the gasses that aren't properly burned. Seth
When you take it off, make sure you get all the plumbing, valves and such that goes to it and back to the engine with it. If you have to go through a smog test like we do, you may not pass the visual or tail pipe inspections.
You may notice a little more power as you will not be operating a pump with the belt and you will not be pumping exhaust gases back in the engine. You may need to rejet the carb or at least readjust it to run better. With the egr and pump I beleive the car is set to run a bit richer. maybe someone else out there can confirm this.
Taking off the smog pump will increase the emissions put out by your vehicle. You may want to check with the laws regarding emissions where you live, if your car doesn't need to be smogged, then it is ok to pull off.
I was gonna say "Boo, Jerm!" (for not promoting free horsepower) then I looked over and saw what I suspected, "Corona, CALIFORNIA" in your avatar. I'm not hammerin ya, it was just an automatic response for me to look. CA is changing governers anyhow, right? Maybe he'll change all the "California Specific" laws, right? "Riiiiight..."
ya, for sure Rick, California has me all up on the defensive as far as emissions compliance. (thank god my mav is now considered "smog exempt" down here. That is the one good thing Cali did, bumped smog exempt cars from 1966 up to 1973. My bro was once pulled over along with a bunch of people, and was subjected to a roadside inspection, looking for illegal parts, etc, they were towing and everything, lucky his car was stock.