Is there really and big diffrence or advatage in using 2.75" pipe over 2.5? I stupidly ordered 2.5" intercooler piping on ebay and I realized I actually needed 2.75 but the inner diameter of the pipe of the XS power intercooler and Greddy elbow and stock piping is extremely close to 2.5. So technically to cause less turbulance and pressure drops in the piping woudl 2.5 be better to use? But I figure with that minimal size diffrence it was just pointless almost and negligable, with stock turbos at only 15 psi or less? I've just been kind of kicking myself for a week now trying to figure out if I shoudl use the 2.5 or send it back and pay in shipping what it would cost to just get reducing couplers? Then again I also found a much better ebay seller with a kit thats kind of the same but offers much better couplers, and additional pipe choices and what not and figured spending a little extra cash and I can get the 2.75" pipe and some extra 2.5 " for the intakes and what not? OR shoudl I just say screw it and use the 2.5 and save myself the 60-70 dollars?

 

the rule of thumb is that you want equal diameters throughout the system, any reducing will bottle neck the flow of air.

just get the right sized ones, don't settle

 

by the looks of it though 2.5 shouldn't bottle neck it.

 

I think u will be fine with the 2.5" pipe. It should be plenty for your application!

 

The greddy 3 row is 2.75 in and 3 out. My apexi 3 row is 2.75 in and out.

 

Just get the correct pipe, it won't kill you.