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With an 05 Turbo, I'm keeping Stock header, but going to replace downpipe. Also replacing uppipe, and have a newer OEM STI one to replace my stocker.


1) I think my stocker has an 02 sensor which i'd need to do some type of mod to bypass emissions or...


2) was looking at new uppipe with 02 bung.


Not sure if this is an issue for performance, but the newer uppipes with bungs are 2 inch in diameter whereas the current STI one is about 1.75. So question is as I'm keeping stock turbo, will the larger diameter tubing from a new uppipe affect performance negatively getting hooked up to stock header comparative to smaller sized OEM STI?


I see on Perrin's site, they recommend the smaller 1.75inch for stock turbo's and 2 inch for larger turbos, so there has to be some logic to this but would value anyones experience with either or conversion


I'd appreciate any insights.

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Radio Shack used to sell a 2.2k ohm resistor to install the female side of the gray EGT connector on the right shock tower. You should be able to find one. I paid, $1.25 back in 2008 when I bought mine. I keep them in the box with the Cobb AP.




IMO, the STI is a better up pipe as it should last forever, after market ones will rust over time.

Edited by Max Capacity

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.


Engine Build - Click Here

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