Ok, so after I got my STi headers ported by Crucial Racing (Thanks Jeremy!!) I was unaware until I finally got my headers back that the cross-pipe remained in stock form. After looking for an aftermarket replacement, I came across the "x-pipe" aftermarket replacement from Bpm, which happens to be one of my favorite aftermarket suby parts mfg.

I promptly ordered the pipe from flatironstuning.com since it was on sale... No sales tax charged Ftw! Since its kind of a new part and a real pita to get any detailed information about up-pipe/header diameter info I want to post my results. It was a complete bolt-on affair and I re-used the oem gaskets. I havent driven my car much after the install, but I can definitely feel that the turbo response better (faster spool since it is less restricted than the stock x-pipe)

Product reference here:

http://www.flatironstuning.com/shop/...d-up-pipe.aspx

Here are the approximate measurements I got:

Stock un-ported manifold diameter: ~ 39 mm

Crucial ported manifolds: ~ 41-43 mm

Bpm Cross-over pipe: ~ 48.5 mm

stock piece to be replaced



fresh out of the box



side by side comparison with un-ported stock header





measurements:





pics after install (bling'-bling')

 

Good buy Jon. I saw that BPM was offering those. They are a very good investent to compliment the P&P Manifold. Personally I run the Injen, same thing.

 

I think they're just that big because piping in the ~ 43mm diameter range can be hard to find. 50mm (which can be ~ 48.5mm ID like you measured) aka 2" is a lot more readily available.

...is a touch excessive...

The Injen is a bit more appropriately sized at like 44 or 45mm.

Glad you like them, Jon! The P&P&C on the manifolds has been EXTREMELY popular and we're still working with a good month long waiting list for them.

...btw... you still owe me the stock cores back!!!!! We NEED them for the core exchange deal to work. Normally we charge a $125 core fee to make sure people return their stock ones and I didn't do that for you. But you have to follow through and get the stock set that I loaned you back to me so I don't feel bad for loaning them to you . Please please please. Think of the people on the wait list

Jeremy



edit... whoops, meant to post from my EJ20Legacy account!... my bad...

 

Hi Jeremy.