I have a 2002 Impreza OBS. If I bought a Magnaflow hi-flow cat with 2 O2 sensor ports (1 before and 1 after), would i have a problem with emissions or cels? I think that I would need to pull off both cats on the stock exhaust and I am hoping that this hi-flow would be ok if both O2 sensors can mount on it. Do I have any other O2s that I am forgetting about? I am also thinking about the 2.25 pipe custom from the cat to the muffler with a new Magnaflow Stainless oval muffler with offset input/output, what else should I be getting? Would this concept work? Also, forgive my ignorance, how does a universal muffler mount to the hangers? Does a shop have to weld the hanger arms on during install? Basically, I have a daily driver that needs a new muffler system and I don't want to spend a ton of money as most of my cash is going towards a wedding and downpayment on a home. I turn to you all for advice.

PS - I have searched and read but most of these related threads are not exactly the information I need.

Hi-flow cats=CEL

Unless you use a fix. Some people have had success with the Mechanical fix.

Jared

Can't comment on the CAT but regarding the universal muffler: the shop will weld new hangers on to the muffler. I've heard that it's better to use the stock hanger positions. Some places like to bolt "fixed" hangers that leave no room for the exhaust to move under tough conditions. This can cause cracking elsewhere in the system.

I'm going with a similar setup for my '04 RS, using 2.25" piping, a Magnalflow resonator in the midpipe, and a Borla universal muffler with oval tip.

Bill

so, for a cat, do I need to go back to Subaru? They charge like $300 bucks for those things. I just wanted to get something that would work for cheap!

should I use a stainless hi-flow exhaust from Magnaflow?

Is your stock cat ruined? If not you could use that. There are tons of theories on exhaust diameter (I assume this is what you are meaning when you refer to the hi-flow). More people than not believe 2.25 is best for your car, with 2.5 being the largest. There are a handful that believe 2.5 should be the min., but they are in the minority.

Stainless will last longer, and cost more. Depends on if you are concerned about corrosion from road salt etc. If you are in AZ, then it probably wouldn't be as important to get SS as if you lived in NY.


Jared

well, I think my stock cat may be plugged. I need to replace it/them while I am doing the custom pipe so it will all be done together.

You would be way better off trying to find one from a member on here. Paying dealer price for the stock cat is crazy. Or go for the hi-flow cat and live with the CEL???

Good luck

Jared

my problem is that in NYS, I have to pass part of the inspection that plugs into OBDII so I can't have any CEL. How can I check to see if my cat is truly plugged up?

well, I think my stock cat may be plugged. I need to replace it/them while I am doing the custom pipe so it will all be done together.
If you haven't done anything to void the emissions warantee, I think it is covered for 80k miles by federal law. Not certain here, but if I'm wrong, someone will say so...

US Federal Law says that the cat has to last 80k. Otherwise, the dealership has to replace it for FREE. I wouldn't mess with it and I'd have the dealership replace it.

Unfortunately, I have 84,000 miles? Now what should I do? There are non-hi-flow cats that are "universal - maybe get one of those for less than $100???

my brullen high flow cat does not throw a cel. so not all cats do...

sometimes all it takes to get rid of the cel with a high flow cat is a bung extender for the rear o2 sensor.

uh huh huh huh... u said bung.

Doesn't the placement of the O2 sensors have something to do with it as well?