Removing Cat???

[98-lgt]

I just got all my intake/ STi exhuast/ UEL header done and it sounds awesome!!! I just want it to be a tad bit louder, so I am considering punching out the cat. Will this throw any codes or anything??? Thanks!

[Snydas_99legacy]

I want to know this also!!

[DOHCEJ22E1]

I wouldn't remove the cat. Your car will definitely throw a code & that would be the least of your issues.

[johnegg]

yes, throw a code and in most states it will keep you from passing inspection.

[98quiksilvergt]

Do you have a resonator on it? Removing that will make it louder, if you have one. If your gonna hollow a cat. Do it to the second one. Closest to the muffler. Your O2's measure before and after the first cat. The second one isn't monitored by the ECU and won't cause any codes. The cat closest to your engine will. You might just want to change the STI muffler to something aftermarket. (yes its an STi muffler but, its still an OEM muffler) I have the unequal header 2 stock cats, and an aftermarket WRX cat back, mine is pretty loud even with the 2 cats.

[98-lgt]

Yeah I think the resonator is still on it. So if I punch out the second cat will it increase loudness/power at all? I really like the sound of it right now, but it could be just a little louder I think. Not sure if I want to go with an aftermarket muffler because it would most likely be too loud or my liking. Maybe just the resonator/second cat removal will be just fine!

[Zues Marine]

i have a 2.5" catback with a 18" resonator speedyracer headers, and a vibrant performance muffler and its a medium loudness.. ive never been hassled by police or anyone else about it...

[98-lgt]

Huh. I would like to hear your car some day. What part of town do you live in?

[98quiksilvergt]

I would start with pulling that resonator off. That's gonna make it louder than removing a cat will.

[98-lgt]

Okay yeah I will most likely do that when I get back. Heading out to Canada tomorrow morning.

[Snydas_99legacy]

So we can get rid of the 2nd cat and throw no codes? If so i plan on replacing the 2nd cat with a resonator.

[DOHCEJ22E1]

So we can get rid of the 2nd cat and throw no codes? If so i plan on replacing the 2nd cat with a resonator.

 

I don't want to be a stickler but check to see if you have a sensor on the second cat. I've owned a 97 & a 98 & they both had a sensor on each cat (1=Pre Cat & 2=Real Cat). I know some Legacies don't have this setup because I've seen them but check to make sure.

[Snydas_99legacy]

okay, what if i do have 2 sensors? Am i screwed?

[DOHCEJ22E1]

okay, what if i do have 2 sensors? Am i screwed?

 

No. As long as the main O2 sensor is able to read correctly & you don't get the 420 code, you're all good. If emissions see a 420 code, instant fail, no questions asked.

[Snydas_99legacy]

How will i know which is my main o2? and can it be moved? Say if its behind the 2nd cat can i put it behind the first? And what is code 420?

And will i run into problems running,

1.header>

2.Cat>

3.Resonator in place of 2nd cat>

4.Rest of exhuast>

[DOHCEJ22E1]

How will i know which is my main o2? and can it be moved? Say if its behind the 2nd cat can i put it behind the first? And what is code 420?

And will i run into problems running,

1.header>

2.Cat>

3.Resonator in place of 2nd cat>

4.Rest of exhuast>

1. No problems here. I ran an EL header before the DOHC swap & it threw no CELs.

2. Cat (as long as the O2 sensor reads that this is a functioning cat, no problems here. You can put this cat wherever you like & would never run into as issue as long as the O2 sensor is reading the oxygen flow from it properly.)

3. Yes, you can put a resonator in place of 2nd cat.

4. The exhaust system has no sensors so you're good here.

 

The 2nd cat is the main cat & you can move it if you want but the O2 must follow it. If a 420 code comes up, you'll need to reset the ECU or get a OBD2 scanner to turn it off.

[Zues Marine]

Huh. I would like to hear your car some day. What part of town do you live in?

 

 

pretty sure you bought that green 'L' bumper from me in the valley right?

[Snydas_99legacy]

1. No problems here. I ran an EL header before the DOHC swap & it threw no CELs.

2. Cat (as long as the O2 sensor reads that this is a functioning cat, no problems here. You can put this cat wherever you like & would never run into as issue as long as the O2 sensor is reading the oxygen flow from it properly.)

3. Yes, you can put a resonator in place of 2nd cat.

4. The exhaust system has no sensors so you're good here.

 

The 2nd cat is the main cat & you can move it if you want but the O2 must follow it. If a 420 code comes up, you'll need to reset the ECU or get a OBD2 scanner to turn it off.

 

oh okay, so would it be best to have a pipe made to replace the first cat? And have a resonator put after the 2nd cat? Or let me state this, what can i do to get the most boxer motor sound outta the car, I would love it to sound like a wrx minus the whole turbogoodness.

[98-lgt]

Nope Justin, I never bought that from ya! Haha

[DOHCEJ22E1]

oh okay, so would it be best to have a pipe made to replace the first cat? And have a resonator put after the 2nd cat? Or let me state this, what can i do to get the most boxer motor sound outta the car, I would love it to sound like a wrx minus the whole turbogoodness.

 

UEL & Muffler. I didn't even have to touch the cats to get the sound. I removed the resonator though. The 'rumble' is actually caused by a slight colliding of the exhaust gases as they leave the UEL to the cat. Your choice of header is what gives you the rumble or not. Your choice of muffler gives your the choice of how loud it's going to be.

 

I ran a custom EL header with my single port heads when I had the 98 but I swapped the heads out completely for EJ25D heads/'99 pistons. This gave me the dual ports I needed to use the OBX UEL header. I had 2.5 inch piping from the cat back & I had an N1 exhaust I had to drill an extra hole in the tip the keep the silencer from rattling. With the silencer off, the rumble sounded DIVINE.

[kujito]

FYI,

 

IT IS A FEDERAL CRIME TO REMOVE/MODIFY YOUR CATALYTIC CONVERTER(s).

 

$2500 fine to you and/or $25000 to the shop/dealer who does it, PER INSTANCE. $5k if you remove and/or gut both cats. Applies to all emissions equipment installed by manufacturer (EGR valve, etc).

 

It's very likely that you will never get caught, but is it worth the risk?

What could you (legally) do to your car for $2500?

 

http://www.epa.gov/air/caa/title2.html

Section 205: Civil Penalties

[Snydas_99legacy]

UEL & Muffler. I didn't even have to touch the cats to get the sound. I removed the resonator though. The 'rumble' is actually caused by a slight colliding of the exhaust gases as they leave the UEL to the cat. Your choice of header is what gives you the rumble or not. Your choice of muffler gives your the choice of how loud it's going to be.

 

I ran a custom EL header with my single port heads when I had the 98 but I swapped the heads out completely for EJ25D heads/'99 pistons. This gave me the dual ports I needed to use the OBX UEL header. I had 2.5 inch piping from the cat back & I had an N1 exhaust I had to drill an extra hole in the tip the keep the silencer from rattling. With the silencer off, the rumble sounded DIVINE.

 

Oh okay sweet, ill leave them then i think lol, also is there absolutly no uel for my motor?? = (

[Zues Marine]

UEL & Muffler. I didn't even have to touch the cats to get the sound. I removed the resonator though. The 'rumble' is actually caused by a slight colliding of the exhaust gases as they leave the UEL to the cat. Your choice of header is what gives you the rumble or not. Your choice of muffler gives your the choice of how loud it's going to be.

 

I ran a custom EL header with my single port heads when I had the 98 but I swapped the heads out completely for EJ25D heads/'99 pistons. This gave me the dual ports I needed to use the OBX UEL header. I had 2.5 inch piping from the cat back & I had an N1 exhaust I had to drill an extra hole in the tip the keep the silencer from rattling. With the silencer off, the rumble sounded DIVINE.

 

so youre running a 2.2 block with 2.5 heads?

 

 

oh yeah,

im on the south hill until the 15th devon,

[DOHCEJ22E1]

Oh okay sweet, ill leave them then i think lol, also is there absolutly no uel for my motor?? = (

There are UELs out there that can be bought but they are hard to find now that MS3 stopped making them. Some Borla 17199s are still out there (careful with these. I've read some things about them, like cracking), or if you are pushed into a corner. get one custom made.

 

so youre running a 2.2 block with 2.5 heads?

I did this with my 98 L about a year before I sold it. It ran pretty good when I was finished with it. Nice power from 2500rpm up to a bit over 6K. Never got it on the dyno though since I worked a lot back then. It pulled 3 car lengths on an old school Legacy SS though. My 98 & my ex-wife's 97 were pretty much my 'learning tools' for Subarus.

[Zues Marine]

generally that would be a bad idea to do that, just because itd lower the compression ratio considerably, great for boosting but bad for n/a driving..

 

but cant argue with results