I have ASM long tubes, gutted cats in the stock y-pipe, and Corsa cat-back. Would I benefit from going to a true off-road y-pipe?

 

Did you leave them gutted with a large open cavity in the cat or did you straight pipe it through? If just gutted form what I've been told it causes back pressure, cause when the exhaust hits the open cavity in the cat and starts swrilling around creating back pressure unlike a straight pipe inserted through the cat. I would go with the ORY if I were you. If you know someone in a shop who does emmisions testing,get it checked to see if it passes with your tune, than ask if he has to look to see if theres cats during the inspection and if not theres nothing wrong with having the ORY!

 

Emissions in AZ are plug-and-play (scan for OBDII codes only) and visual inspection. I just passed a month ago and renewed my registration for 2 years so it will be awhile before I have to worry about it again. Last time though they didn't even look under the truck at all.

Anyway, the gutted cats are just gutted, no pipe through them.

 

Just weld pipes through them so you wont have problems with inspection.

 

Aren't the ORY's usually a larger diameter?

 

Yea, probably 3" but im not positive on that.

 

I'm sure that I have enough flow through the headers and cat-back, but I am still running the factory 5.3 y-pipe, so I am wondering if that is going to back things up some. I'm sure I would see some benefit but the question would it be enough to justify having a custom one made, cause I'm pretty sure that's what I would have to do.

 

I have the pacesetter ORY and it's 3" If you wanna keep the cats do like I said before and put a pipe straight through the cat you'll have to do a little cutting to get the 3" pipe to fit than just weld in place. Stock Y is 2.75" I think. I would do all 3" back if I where you, especially w/ a sc.

 

You may see some small gains, but I would be currious if its worth the cost of getting one made. If I remember correctly the Pacesetter ha a little extra, your shop may be able to weld a flange on that, then a small intermediate pipe from your ASM's to mate up with the Y, but Im not sure how much modificating it would take. May be best just buying a few mandrel bent 90's and going to a shop.

 

I had mine fabbed for for 120 bucks and that included putting my dual cutouts in it. its all 3" as well... I'd get one made for your truck specifically. since you are supercharged + 4WD + motor swapped... get it like you want it IMO...