So, I've been working around Subarus for the last three years where the biggest power adder from stock was a higher flowing downpipe. I have found Full-Race makes a short downpipe for $145 and Greddy makes one for $165. There's no way I'd pay more for a Greddy part than a Full-Race unless it offers a lot more. The way I see the Greddy one working out because it looks longer is Downpipe-Catback and the Full-Race one would go Downpipe-Test pipe-Catback correct?

Do downpipes even make power on Evos? I was going to do it all at once when I got my car and broke it in. FMIC upgrade, piping, full exhaust, intake, ebc, wastegate actuator, fuel pump, etc and then have Tim Bailey have a try at tuning it.

 

Well, now I'm seeing that exhaust systems like the 5Zigen may have a built in downpipe where it bolts up to the turbo?

 

i think most of the exhaust out now are just catbacks, including the 5zigen. i think bushur or ams did some test with downpipes and they didn't see much gains since the stock one is pretty well built already

 

Well that sounds good to me, I have read a little bit about them and they say they can increase throttle response which sounds good to me. If they do, $145 isn't bad for a full-race piece.

 

Well, there is another side to the story though; the downpipe in the EVOs aren't really technically "true" downpipes because they don't go all the way to the turbo. They only connect to the O2 housing which in the X's case is the most restrictive part of the system. Also, in the X's case it technically isn't an O2 housing because there's no O2 sensor, so it's actually just a turbo outlet piece now.

Either way, AMS foundthat by making a 1 piece turbo outlet elbow and downpipe combo (creating what is really a true downpipe) that there was about 10 hp to be gained. Buschur confirmed this as well, and I think that many companies are gonna be coming out with various versions of "true" turbo back exhausts in the near future, so there is good hope for big power in the X. It's already making as much power with a cat back and tune as a catless turbo back and tuned 9, so things are looking promising!

 

Thank you STi2EvoX, as an ex STi owner you know what I was trying to say. Thank you for the information I will be watching for that release.