I have taken off my intake plenum to give is a good cleaning, now I'm considering giving it some port work. My question is, did gm intensionally design it in a specific way to get the air to tumble? Would porting the portion behind the tb or the holes to the runners counter this? I have searched porting, and know what has been done, but I am wondering if the design has any merit to it having obsticals in certain areas. Any and all feedback, hints or ideas is much appreciated.
Thanks,
Jim

 

A bunch of the members including myself have ported the plenum to help the air flow through the piece. Search the boards for "plenum porting" or something along those lines and you'll find tons of information on it. also check out these sites and they should answer most of your questions.

http://216.121.161.76/files/PlenumPorting.pdf

http://www.geocities.com/jgkov/PRPort.html

 

I can't imagine GM purposefully obstructing air to turbulize it. Everyone on this board whos done any port work to thier upper plenum can attest that it will marginally increase performance and not hurt it in the least.