304 stainless exhaust

[DaveT]

I am thinking of having a custom exhaust system made for my 92 Loyale:

 

http://www.pipesmith.us/

 

Or maybe doing it myself. Welding isn't a problem.

 

My main uncertatnies involve the cats. I want to make a Y pipe that goes to a flange, then a "standard" performance cat, to replace the stock Y with the built in one. From there, another flange to a second cat (assuming I need 2 because the original has 2). Then stainless to the stock muffler flange. All with flanges. All real stainless, not the crap that only lasts 6 years, or the flanges rot off because they are not stainless.

 

SPFI

So the quesations:

 

What diameter pipe would be best?

1 or 2 cats? (I need to pass emissions)

Any muffler sugestions? Not looking for loud.

Cat brands worth looking at?

 

Thank you.

[4x4_Welder]

The last time I went through CT emissions, they just checked to see if there was a cat there. If the tag under the hood just says catalyst, then you can sneak by with just the one.

[robm]

It is my understanding that the Subaru has 2 cats because they do different thngs, i.e. they aren't 3 way catalytic converters. The first one deals with CO and HC, the second with NOx, or vice versa, I don't know which is which. A replacement cat would be a 3 way, so a second cat would not be necessary.

 

Stick with stock diameter to the Y, to keep the velocity up for better scavenging. 1-7/8 or so after. This diameter worked well on 510's, and these engines aren't much bigger, and don't breath as well.

[beataru]

Yeah they shouldnt do a sniff test becuase that would require a fourwheel dyno... so just say.... "unless you want to buy me a new drivetrain i suggest you dont test it!" Thats all i Should of done with my Gl-10 but i Stupidly told them that It was 4wd instead of AWD oh well.... next time!!!

[robm]

Actually, a 4 wheel dyno is not required, as the Loyale is 4WD, with a button to switch from 2WD to 4, not AWD or FT4WD. As long as they know the hand brake is on the front wheels....

 

Oh, and the cat should be right at the Y. Other threads on this board seeem to indicate that there needs to be a large plenum right there to work best.

[beataru]

Actually, a 4 wheel dyno is not required, as the Loyale is 4WD, with a button to switch from 2WD to 4, not AWD or FT4WD. As long as they know the hand brake is on the front wheels....

 

Oh, and the cat should be right at the Y. Other threads on this board seeem to indicate that there needs to be a large plenum right there to work best.

Yeah i know its not required... but what emissions guy knows that! they even asked me if it was AWD and i stupidly says no if FWD i am retarded... ohwell i guess having a WRX downpipe cleans up emissions reall good.. it passes with that of what a new car would be trying hard to get.... haha runon sentence!