single port exhaust

posted in catalytic converter thread about my cat but I figured I'd just see what I could get in my own topic. my header has no holes as of now but will bend if you squeeze it just right, BY HAND. my cat smells like a trash truck pretty much all the time. I can weld all my pipes. keeping car until it turns into a pile of rust. live in NH so it needs to pass obd2 emissions test. "no exhaust sniffer". as of right now im having a little trouble finding what the inside diameter of a single port header flange is, "I want to build my own" I have around 300 dollars right now. don't want to spend more than 400 tops. anyone got any ideas? oh yea, I want it to rumble, LOUD.

I just ordered one of these. he has mild steel for 60 bucks less I believe.

 

http://www.ebay.com/itm/subaru-2-2L-single-port-UEL-exhaust-headers-stainless-/221364871786?pt=Motors_Car_Truck_Parts_Accessories&hash=item338a5fe26a&vxp=mtr

the pipe where the two meet seems way too large in diameter to me

yes it does, I know when I get an exhaust leak because my throttle response goes out the window. plus, that kind of defeats the purpose of building it from scratch, Its still 240 after shipping in mild steel. I could build it myself for less than 50 in mild steel. I just need to know if there's more than 1 size single port flange, and what kind of cat will last and keep it legal, no, I don't want a Subaru cat.

The flanges should all be the same, you could even just cut yours off the original manifold and use them with your new tubing, if you are planning to weld that up yourself just get a weld on cat from cnt or local auto parts stores.

Most aftermarket cats are garbage for Subarus. I would find a good used cat if yours are clogged, or do an O2 Sensor spacer mod to defeat the PO420 code, if that is in fact what you are trying to do. My Father-in-Law bought a Subaru with new aftermarket cat and it throws PO420 off and on.

^I agree with that for sure, subaru cats are very good reason why they cost what they do. The cat on my 1990 lego is original with 292k on the odo, and working great.

 

Honestly for the money, I would by a bolt in stromung or cnt high flow cat.

The flanges should all be the same, you could even just cut yours off the original manifold and use them with your new tubing, if you are planning to weld that up yourself just get a weld on cat from cnt or local auto parts stores.

 

original flanges have pretty much had their day, plus new ones are only like 10 bucks each.

Most aftermarket cats are garbage for Subarus. I would find a good used cat if yours are clogged, or do an O2 Sensor spacer mod to defeat the PO420 code, if that is in fact what you are trying to do. My Father-in-Law bought a Subaru with new aftermarket cat and it throws PO420 off and on.

 

wouldn't the spacer screw up the computer air fuel ratios? or would it just be the rear o2, not the front?

A piece of 1/4 inch plate is going to cost that much unless they are in the business of selling the drop metal as well. If you ask me $10 isn't bad for some pre-made flanges. There is no way your going to fix your exhaust without spending a little money. Outside that go to a junkyard, if you were in my part of the states I would charge you ten bucks for one of the two I have. BTW I'm not shipping them because you would have to spring for it.

you have flanges?

Well yeah, welded to my exhaust manifold..hope I don't sound rude but I won't cut them off and send them to you, price and shipping will cost more than it will take for you to trudge out and snatch some off a junked out exhaust..sorry.

You just space the rear O2 Sensor, as that sensor only monitors the performance of the Catalytic converter. The rear O2 spacer mod works for all Subaru's, personally confirmed by me and my buddy's Subaru Shop up until the First PZEV "H4" in 2004. From 2005 onward, rear O2 is used for fuel trims.

You just space the rear O2 Sensor, as that sensor only monitors the performance of the Catalytic converter. The rear O2 spacer mod works for all Subaru's, personally confirmed by me and my buddy's Subaru Shop up until the First PZEV "H4" in 2004. From 2005 onward, rear O2 is used for fuel trims.

 

have a link for said spacer?

and by that logic could I just delete the cat, install a resonator and a bung for o2 sensor and spacer? they do "emissions" for inspection in NH but its not a sniffer, just an obd2 plug in.

Can't find the write-up I used, but this person lays it out at RS25. Basically, take a spark plug antifouler that is the same thread as your REAR O2 sensor, drill out the antifouler, and screw it into another one. Tighten the assembly, re-thread into the cat and tighten. You will need torches to heat and remove the REAR O2 sensor, and be prepared to replace it if it breaks. DO NOT TOUCH OR DO THIS TO THE FRONT SENSOR

well both of my sensors are new within the last 6 months. kept throwing CEL's until I found out it was just a clogged fuel filter, changed under hood filter, 5 minutes of driving later CEL turned off.

^lean condition?

yes. as well as I believe an "open circuit". had quite a few since I bought the car. had it 3 years and this is the first time I've replaced the fuel filter.

oh, i bought a fuel filter when i bought the car, lol. something i do on anything i don't know the history of.

and by that logic could I just delete the cat, install a resonator and a bung for o2 sensor and spacer? they do "emissions" for inspection in NH but its not a sniffer, just an obd2 plug in.

 

I didn't say that...

but if I "hypothetically" did that, I could get away with it *wink wink*