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Reply With QuoteThat pipe looks like a pain to get off...I have my catless one sitting right here. I could always keep it in there because with that cat, I may be able to pass emissions.
This is a discussion on Gutting Catalytic converters within the Engine Performance forums, part of the Tutorials & DIY category; Originally Posted by mittermiers you are talking about the catalisator that is located after the exhaust manifold and before the ...
Originally Posted by mittermiers
you are talking about the catalisator that is located after the exhaust manifold and before the turbocharger?
I ve gutted it but you will not be able to do that with a large screwdiriver or a dril. I couldn't even hammer cat out. I had to cut pipe in half and gut it with a hydraulic press
so prepare for some welding
That pipe looks like a pain to get off...I have my catless one sitting right here. I could always keep it in there because with that cat, I may be able to pass emissions.
that cat is the one that must go the last thing you want is the Cat to break up and enter the turbo.
if you want to run more than stock boost it has to go.,
"It is at our most challenging times that we must cheat our very hardest" - Eric Theodore Cartman
Yea you're probably right. Now I just gotta get off my ass and do it... The thought of that cat breaking apart and going into the turbo really motivates me to do it.
I'm considering doing this on a weekend here soon... couple of questions though... is this something i can do in a few hours... or is it something i should wait till i have a whole weekend to do? and with the up-pipe cat removed... should i expect any problems throwing codes or anything wierd?
yup
Yes you will throw a EGT sensor code. Egt sensor is the sensor sort of like an 02 sensor. But in the subaru service manual it is called a Air Fuel sensor or A/F sensor. When you de-cat the up-pipe you will want to plug the hole. There is a specific bolt size required M12x1.25 bolt less than an inch long (cut if necessary). I bought mine at NAPA and it cost me about $4.50.
Then to fix the CEL you will get when you pull the wire that is connected to the A/F sensor. You will pull the from the plug you will need a 2.2k-Ohm 1/2 watt resistor. This you can get a Radio Shack in a pack of 5 for a total of $1.06 including tax. You only need one though. After the wires of the the resistor are plugged into the socket you should have no problem with a CEL.
Here is my source for most info. http://webpages.charter.net/baraboo_...ppipe_fix.html
Last edited by Starch; 03-03-2008 at 07:13 PM.
02 WRX Wagooone!
Yea that is definitely a weekend job. Whats this about the 2.2 ohm resistor? I don't really understand how that works? Take the sensor out, stuff the hole with a screw, so we are left with a bare sensor. Take the sensor off, and put a 2.2 ohm resistor in the terminals? Just want to make sure I got this part right.
In the up-pipe there is an 02 sensor or A/F sensor whichever you prefer to call it. Out of the back of the sensor run I believe two wires. The wires connect to a clip type plug that plugs into a panel which is somewhere near the passenger side firewall. When you unclip the plug you stick the two wire ends of the resistor into where the plug used to connect.
I believe you have it correct. I am trying to explain it as simple as possible because I know things like this can be tough to interpret without images or knowledge of the parts. Any more questions ask away.
02 WRX Wagooone!
No that makes perfect sense now. It is basically faking the presence of the O2 sensor. You know, I wonder if the car can pass emissions with the cat in the up-pipe as the only cat in the exhaust system. Of course, after inspection, swap with cat-less up-pipe. I plan on testing this out soon at an emissions place. Hope they're open on Saturday...
yeah thats precisely it. The resistor offers equal resistance to that of a normal 02 reading.
And from my understanding as long as your car is warmed up and has been driven a lil bit you will pass inspection perfectly with the joint pipe de-catted.
Subaru put that cat there to make the car pass emissions testing when cold. Cats dont work unless they are warmed up so they put that cat close to the manifolds so it heats up quickly and lowers emissions until the other two cats can get warmed up and start working properly.
*EDIT* I guess I didn't read your post well enough. You are talking about emissions testing with only the pre-cat in. I was talking about emissions testing only having removed the pre-cat.
You will fail emissions testing running only the pre-cat. Plain and simple.
Last edited by Starch; 03-04-2008 at 07:23 PM.
02 WRX Wagooone!
Hey you never know until you've tried. I am going to try this Saturday hopefully. Maybe even sometime this week if I have time. If I pass this inspection (North Carolina) then we will know an easy way to pass emissions when that time of year comes around. The only 2 things that make me doubt I'll pass is that you are sure I won't, and that when I rev high and let off the gas I get fire out the tailpipe. lol maybe it will have good CO, CO2, and NO2's but high HC's.
Let me know how it goes for you. Post your results up when you get them.
02 WRX Wagooone!
I went to a place to do the North Carolina emissions test. It was a joke. I told them I wanted to an "offline test" not to be sent to the government. All they did was plug an OBD II plug to my car and read checks of my exhaust and fuel components. I didn't even have to turn on the engine! He said I passed. I was like, how is that an emissions test? lol. They said they check for presence of a cat and check all your systems with OBDII. No putting the car on a dyno and putting sensors on the exhaust tip. I wanted to do a California style emissions test, but they don't offer it here in North Carolina. Anyone from California that can test to see if the up-pipe cat will pass emissions?
I finally got around to getting the 2.2k Ohm resistors. Now, I know to replace the o2 sensor in the uppipe, but there is the main o2 sensor in the main exhaust piping. There are 4 wires running from it. Does anyone know if that o2 sensor matters and if it does, which 2 wires require the resistor?
The UP has a EGT not a 02 Sensor in it.
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