Quote:

Flow would increase, but you're thinking about it wrong. The motor doesn't know it's boosted mechanically or not. Vacuum is often used incorrectly. The engine doesn't see vacuum, it sees reduced pressure. N/A the engine sees atmospheric pressure. If you add 1 bar under boost, that's a total of 2 atmospheres. So the flow bench would have to have the pressure drop increased. I've done it out of curiosity and a port that went turbulent at 28in did indeed flow more air at 35in. I don't know what the numbers are exactly, but more pressure will force more air through the same size hole UNTIL you've got the port saturated. Which is why I go for volume on engines I know are going to be boosted.



THIS ANSWER RIGHT HERE IS ABOUT AS CLOSE TO ANY I HAVE HEARD COME FROM PROFESSIONAL TURBO RACERS ABOUT HEADS!!!!

I've had the privilege to hear and pay attention when questions about building Turbo Motrs were brough up and HEADS was always the HOT TOPIC!!

Everyone of them said your heads is where it's at! Buy the best flowing heads you pocket $$$$ can stand and go from there. The turn radius and stagnant port flow that N/A guys worry about doesn't apply as much to Boost.

Look for Port Volume and Flow the more the better.

I wish more people would flow their heads like dodgeboy11 did, especially when they know they are being set-up for Boost.