the chargepipe going from my compressor housing all the way through both sides of my JRC 6" intercooler is 2.5", so i ordered an ebay CAI to make my upper chargepipe, but the problem is it comes in 3" (even though it clearly said 2.5" diatmeter on the ebay auction). i'm kind of stuck with it. i guess the quesiton is will i have any type of air flow problems if i mate the 2.5" charge pipe to the 3" charge pipe? i think i may have read somewhere that the volume of air is affected if the same diameter charge pipe is not used throughout the whole charge piping system.

 

slightly slower spool up, won't be noticeable.

 

you also won't be able to mount your bov on the CAI unless you have access to a tig or jbweld

 

yeah i know. i have a greddy type s steel bov flange. so i'm gonna have to weld it to the lower charge pipe.