I am attempting to build an intake setup for an engine I'm working on. I currently have a 3" diameter aluminum pipe on the throttle body that just curves off to the side. I would like to try and get some cooler air by routing it down into the bumper. I have access to 2.5" diameter piping. I was thinking of just expanding the 3" pipe with the 2.5" pipe into the bumper. This would mean that the air coming in would be into the smaller pipe and about half way to the TB, it would expand into the larger pipe. I know if the diameter increases, the velocity of the air will decrease, but would this affect performance of the engine at all? Any input on this would be greatly appreciated.