So I bought two upipes for the price of, well, $30. One is a brand new ss autochrome and the other is a maddad style with a flex joint like this one--->http://www.daddysscp.com/dcart4/product.php?productid=53&cat=7&page=1 MY question is when I measured the pipes here was the results inlet outlet ss auto chrome 2.5" 2" maddad style 2" 1 7/8" Now which one do I install?? Will a larger uppipe like the ss cause a pressure drop or will it make my turbo spool faster? Or will the maddad type keep a better pressure gradient across the board and thus have better on boost response? I'm not sure what the outlet of a stock wrx manifold and the inlet of the turbo flange is, so if anyone has those measurements it would sure help. Also the ss uppipe is a bit longer than the maddad one. ALso the flex joint on the madmad unit looks to be better quality since the inside has an inner piece in addition to the outside flex "wire" connection. The ss has the wire mesh on the outside and the inside as well, leading me to think it would be more likely to fail. any suggestions? I've got a 2003 wrx wagon with cobb stage 2 and a catless dp and full hks carbon ti exhaust and the catted uppipe obviously.
The opening of the port isn't as important to the equation as the ID throughout the pipe. In fact, I'd be more concerned with the ports on either end of the pipe matching the ID of their ajoining exhaust piece, be it the turbo hotside or passenger side header collector...not with which one is bigger.
What you want it the smallest pipe you get get that doesn't raise backpressure. You want to keep the velocity high, when you increase the diameter of the pipes without increasing flow, you are killing your spoolup. So basically you want the pipe that is closest to the factory header diameter. Other will tell you that I am wrong just to sell some parts, but the main focus before the turbo is a high exhaust gas velocity. Anything after the turbo is just a matter of getting the air out (ie, bigger is better). Russ
what about a 3in x-over into stock manifolds??? does that principal still apply.. was thinking off making 100 of them... ps... I am truly joking....... they will only be 2.5inches... ha ha ha
