Cutting out the cats, will I mess anything up?

[grayguy]

Ok, I want to do my exhaust tommorow, but I'm not sure what to do about the O2 sensors. If I'm running no cat, with the O2 sensor's reinstalled, is the CEL going to effect my ECU at all? I know on some cars certain CEL codes will put the ECu into safemode. So basically, I need to know if I'm ok just running with the CEL on constantly until I can get the O2 sensor to be happy (I assume an anti-fouler will take care of that?) ?

[Huffer]

You'll need a boss for the rear O2 sensor.

[grayguy]

You'll need a boss for the rear O2 sensor.

What do you mean by a boss?

[Wiscon_Mark]

It's a O2 sensor spacer that plugs into the cat pipe.

I'd recommend you rethink going catless, and get a nice hi-flow cat instead.

[backpack09]

boss or bung, it is just the threaded piece that you screw the o2 sensor in.

A rear o2 sensor is only used in obd2 cars to make sure the cat is working. All the computer is looking for is a different reading between the front and rear o2 sensors. You may be able to avoid the CEL entirely by picking up a "spark plug anti fouler" from the help section in partsamerica And using it to pull the rear o2 sensor out of the exhaust stream a bit.

I used this on my mazda after I replaced the rear cat, and the CEL came on for the front cat. Rather than welding in a new bung, and extending wires, I simply put the anti fouler in the bung and the sensor in the antifouler, and the CEL never came back.

[sheepdog]

Yea, it kinda just works like a spacer. However, stripping the cats out of a stock exhaust is kind of a waste. Get an aftermarket exhaust with no cats. Then sell your stock one to someone who needs the cats, they're expensive. You could even trade them for the one with their dead cat, and gut that one if you want.

[grayguy]

Well I wouldn't be taking the cats out if I were leaving a stock system, duh. I already have my header on there, so it's going 2.5 from the header into my Moroso Sprial Flow muffler, then about 18inches of 2.5 into my 2.25 Magnaflow straight through, then 2.25 all the way back until the last 12-18 inches where it goes back to 2.5. This is the exact same setup I had on my other car, and it sounds uite nice.

Ok, I figured the boss was just another word for the O2 bung. Hopefully when I go get my Flange and hangers they have 2 of those as well, then I can hopefully have everything figured out and welded up tonight. Thanks.

[Wiscon_Mark]

If you're going that big of piping, might as well replace all the stock stuff and go full 2.25 or 2.5.

I dunno, you're probably going to feel robbed of torque with that 2.5 setup.

[grayguy]

What are you not understanding here...there wont be any stock piping left at all...and I only have 2.25in manderal bends lieing around, so it looks like it's gonna be 2.25 for everything besides the spiral flow that's 2.5 and the "tip" (aka last straight section)

[StatGSR]

hey max give me a buzz tonight.

[Wiscon_Mark]

What are you not understanding here...there wont be any stock piping left at all...and I only have 2.25in manderal bends lieing around, so it looks like it's gonna be 2.25 for everything besides the spiral flow that's 2.5 and the "tip" (aka last straight section)

Well, why are we talking about gutting the cats then? You'd just be taking the whole assembly out.

[grayguy]

hey max give me a buzz tonight.

will do. you have class till 3 right? Just give me a call when your done. Unless I'm at steve's house whre I don't always get reception, I'll answer...

[StatGSR]

[

Well, why are we talking about gutting the cats then? You'd just be taking the whole assembly out.

nobody ever was talking about gutting them out... he said cutting them out, like remvoing them from the exhaust system.

and yea max im done at 3 so ill try to give ya a call then.

[Wiscon_Mark]

Oh jeez.

This whole time I thought he was gutting them. misreading FTL :lol:

[grayguy]

Yeah, i'm not cutting up any of the stock exhaust. it's all coming off incase i want to ever return the car to stock.

[sheepdog]

Oh jeez.

This whole time I thought he was gutting them. misreading FTL :lol:

Haha yea I thought the same thing, sorry for the confusion. With the spacer (bung) there won't be any issues.

[scottzg]

why aren't you running a high flow cat? its really selfish to run catless.

[sheepdog]

why aren't you running a high flow cat? its really selfish to run catless.

Lol then I'm selfish too. Screw cats, they're expensive.

[StatGSR]

why aren't you running a high flow cat? its really selfish to run catless.

because no emission laws is one of the perks of mn, and u do know that high flow cats are nothing more than resonators right.....

[Wiscon_Mark]

Maybe cheapo ones on ebay, but that's not true of a good hi-flow cat (ie: Stromung). I can actually see the metal substrate if I look in it, it's definitely the honeycomb they use in catalytic converters.

[StatGSR]

well i suppose, but have fun spending hundreds of dollars on that..... haha.

[grayguy]

call me selfish if you want I dont' really care. We just finished my exhaust up. It sounds fricken awesome! Including the header, I have $235 into this exhaust, so I'm not complaining!

[StatGSR]

good to hear u got it finished max!

[sheepdog]

nice! sound clips please :)

[grayguy]

I'll try to get a sound clip today and post it up tonight.

[StatGSR]

back from the dead... sound clip of said exhaust....

https://sl-i.net/FORUM/images/imported/2008/03/th_LGT-1.jpg (http://s4.photobucket.com/albums/y105/StatGSR/?action=view&current=LGT.flv)

[grayguy]

Man I miss that sound...I'm gonna have to buy another subie and leave it NA.

[Sarra]

**** What transmission is that where you can shift at 55 in second gear? I'm hitting rev limiter at 50 in mine. :(

[StatGSR]

^ its just a 98 GT stock tranny

[Sarra]

^ its just a 98 GT stock tranny

Why the hell is the gearing different then? *Is epically confused*

[Plays_with_Toys]

differentials :wink:

Outbacks have a different final gearing ratio too. My car hits redline hard at 50mph as well, and my car won't rev over 6000rpm on the dot.

[Sarra]

Ahhh. Mine revs to 6,300 rpm then hits rev limiter.

[makipsee]

kinda bring it back from the dead but i have a 95 leggy wagon 2.2 i also cut out the cats.. i doubled up on the spacers for the rear o2 but im still getting a CEL... any other cheap options? and whats the resistor trick that i keep reading about?