What size exhaust are you running before and after the turbo?

I am running stock exhaust and manifolds. The single pipe after the Y (3") reduces down to 2.5" where it elbows into the exhaust turbine. I assume to increase velocity. 3" single exit that I am cutting off tomorrow in favor of dual 3" resonators. No mufflers/ no cat. (The turbo acts like a loud performance muffler while idling and cruising)

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The turbo acts like a loud performance muffler while idling and cruising

Yeah, and screams when you put your foot into it, lol. I believe its 3" off my headers then 2.5 on the piping that comes with the STS kit, as Darryl said. I Y-piped it after the turbo again into 3" pipes and out the roll pan .

If you're running a stock motor/stock heads, you are best to stick with the factory manifolds, and piping up to the turbo

with my current setup, I have ported heads, so I upgraded to 1 3/4" long tube headers with a 3" diameter collector. (collector length can vary from different manufacturers) After the headers I have High flow cats which go from 3" just after the header, then reduced to 2 1/2" through the cats. The piping to the y-pipe remains 2 1/2", and the y-pipe itself becomes 3", then 3" right back to just before the turbo. I welded flanges to the turbo piping, for easier removal (maintenance purposes), and I also increased the diameter of the first 18" of the sts turbo pipe to 3" as well. I took a bunch of measurements while I had everything apart, and I will be fabricating a full 3" diameter pipe with u-bend right up to the turbo, then dual 3" pipes after the turbo.

I have shorty headers to 3" stainless no cat to turbo and 4" out w/ a short magnaflow muffler... It definfitely spools up faster than with the original sts piping...

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Originally posted by "Av'sFan":
I have shorty headers to 3" stainless no cat to turbo and 4" out w/ a short magnaflow muffler... It definfitely spools up faster than with the original sts piping...

I noticed a difference too!!

Hurry up and get that truck finished Steve so you can dyno it buddy!!!!