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Old 08-21-2008, 11:20 AM   #1
Malasubidude
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Default Will getting a new muffler increase performance? Or do I have to get a full cat-back?

I can get a new muffler and mid-muffler for just $150 from Borla, but for their cat-back they want $500?

I really need advice! I want to do something with my exhaust because right now it's just horrible...

Here's the muffler http://www.car-stuff.com/carparts/su...bo2295551.html

And heres' the cat-back http://www.car-stuff.com/store/?N=11...719+11920+9292
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Old 08-21-2008, 11:22 AM   #2
fatgroundhog
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That muffler looks like it is OEM replacement...so probably no real gains in performance. If you want gains, you'll want a different type of muffler. The muffler on that catback is different. If you want to save money, find a nice local muffler shop and see what they can do for you. They'll probably have some good options that will help you NA motor breathe a bit better, but won't hurt your wallet too much.
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Old 08-21-2008, 11:51 AM   #3
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Alot of the performance gains on a N/A motor are gained from an increase in piping diameter. Yea the muffler does help a bit as well. +1 for going to a local shop. Sometimes you can get them to price match as well. See what they'll charge you for the custom work, then tell them you can get the same system to your doorstep for a few bucks cheaper and see what they say. It cant hurt, but I'll bet that the local shop will be better priced regardless.
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Old 08-21-2008, 11:56 AM   #4
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Quote:
Originally Posted by ammo0000 View Post
Alot of the performance gains on a N/A motor are gained from an increase in piping diameter. Yea the muffler does help a bit as well. +1 for going to a local shop. Sometimes you can get them to price match as well. See what they'll charge you for the custom work, then tell them you can get the same system to your doorstep for a few bucks cheaper and see what they say. It cant hurt, but I'll bet that the local shop will be better priced regardless.
Negative on the piping diameter. Bigger is not always better. Keep the piping stock size (2.25") for at least the mid-pipe. The axle-back and be whatever size really and you won't loose any.

As for performance gains, you won't get anything from a muffler or even a catback really. The gains from changing your cat and headers. After your cat and header, changing the midpipe and such may be of some benifit.

The muffler is mainly what changes the tone, and everyone wants a good rumbly tone of course.
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Old 08-21-2008, 11:11 PM   #5
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Where's the gif of the kitty biting the hand as it goes to press the new thread button...

This guy seriously needs it.
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Old 08-21-2008, 11:24 PM   #6
RallyPig87
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Put it this way, any catback you get will make give your subaru that boxer rumble. IF your looking for noticeable performance and for that budget get a downpipe.
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Old 08-22-2008, 12:52 AM   #7
williaty
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OK, first of all, the guy has an NA car, so no up/down/sideways pipe.

Second of all, the guy's stock piping is something like 1.8". 2.25" is the optimal size for the 2.5L NA motors. If it's one of the older 1.8L or 2.2L, then you'd want to drop down to 1.8" or 2" respectively.

OK, so that corrects the things people have gotten wrong so far.

In an NA car, nothing after the headers and cats matters. Your muffler and midpipe (which together make a cat-back) can not give you any gains. The only thing they can do is change the sound. So long as you don't put the muffler from a 600cc moped, you're also not going to cost yourself power either.

To make power in the NA exhaust world, you have to change the headers and cats. For your year, you have the option of unequal length (UEL) headers or equal length (EL) headers. The difference is wither or not the pipes are the same lengths (obviously). EL headers make the most power gains (by a pretty big margin) but smooth out the engine sound a little bit. It'll still sound like a Subie/rumble. No, it won't sound like a Honda. UEL headers show smaller gains (but still better than stock) but rumble like a purring tiger that just ate a running Harley.

For the cats, you have two options, High Flow Cats (HFC) or catless (trackpipe). HFCs don't kill you or the environment as much and will probably pass emissions if you get a good one. You get decent power gains too. A trackpipe will show bigger gains, be loud as motherfrakingheck, will definitely fail emissions, and will destroy the world for your children.
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Old 08-22-2008, 03:00 AM   #8
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Quote:
Originally Posted by williaty View Post
OK, first of all, the guy has an NA car, so no up/down/sideways pipe.

Second of all, the guy's stock piping is something like 1.8". 2.25" is the optimal size for the 2.5L NA motors. If it's one of the older 1.8L or 2.2L, then you'd want to drop down to 1.8" or 2" respectively.

OK, so that corrects the things people have gotten wrong so far.

In an NA car, nothing after the headers and cats matters. Your muffler and midpipe (which together make a cat-back) can not give you any gains. The only thing they can do is change the sound. So long as you don't put the muffler from a 600cc moped, you're also not going to cost yourself power either.

To make power in the NA exhaust world, you have to change the headers and cats. For your year, you have the option of unequal length (UEL) headers or equal length (EL) headers. The difference is wither or not the pipes are the same lengths (obviously). EL headers make the most power gains (by a pretty big margin) but smooth out the engine sound a little bit. It'll still sound like a Subie/rumble. No, it won't sound like a Honda. UEL headers show smaller gains (but still better than stock) but rumble like a purring tiger that just ate a running Harley.

For the cats, you have two options, High Flow Cats (HFC) or catless (trackpipe). HFCs don't kill you or the environment as much and will probably pass emissions if you get a good one. You get decent power gains too. A trackpipe will show bigger gains, be loud as motherfrakingheck, will definitely fail emissions, and will destroy the world for your children.
/thread

btw its people like you that make me happy to live
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Old 08-22-2008, 03:04 AM   #9
williaty
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Quote:
Originally Posted by Stivie View Post
btw its people like you that make me happy to live
umm.. thanks... I think....

btw, I'm straight, sorry dude











nah, just kidding. It's nice to know at least some people appreciate the truth rather than wanting to argue about it.
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Old 08-22-2008, 03:22 AM   #10
raheezy69
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Quote:
Originally Posted by cmiovino View Post
As for performance gains, you won't get anything from a muffler or even a catback really. The gains from changing your cat and headers. After your cat and header, changing the midpipe and such may be of some benifit.

The muffler is mainly what changes the tone, and everyone wants a good rumbly tone of course.
exactly. it's a misconception that adding a catback adds performance.
if you have stock headers and stock cat, you are only freeing up flow from the cat-back, which really adds close to no whp increase.
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Old 08-22-2008, 05:40 AM   #11
fatgroundhog
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Are the exhaust manifolds and cats in the NA Subarus restrictive? Can't always assume that a car needs exhaust work at these points (though it depends on where in the power band you want to improve). Some cars in fact pick up power changing out mufflers since that's where the bottle neck is. I don't know about NA Subarus though...
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Old 08-22-2008, 06:05 AM   #12
bigrobwoot
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Quote:
Originally Posted by williaty View Post
OK, first of all, the guy has an NA car, so no up/down/sideways pipe.

Second of all, the guy's stock piping is something like 1.8". 2.25" is the optimal size for the 2.5L NA motors. If it's one of the older 1.8L or 2.2L, then you'd want to drop down to 1.8" or 2" respectively.

OK, so that corrects the things people have gotten wrong so far.

In an NA car, nothing after the headers and cats matters. Your muffler and midpipe (which together make a cat-back) can not give you any gains. The only thing they can do is change the sound. So long as you don't put the muffler from a 600cc moped, you're also not going to cost yourself power either.

To make power in the NA exhaust world, you have to change the headers and cats. For your year, you have the option of unequal length (UEL) headers or equal length (EL) headers. The difference is wither or not the pipes are the same lengths (obviously). EL headers make the most power gains (by a pretty big margin) but smooth out the engine sound a little bit. It'll still sound like a Subie/rumble. No, it won't sound like a Honda. UEL headers show smaller gains (but still better than stock) but rumble like a purring tiger that just ate a running Harley.

For the cats, you have two options, High Flow Cats (HFC) or catless (trackpipe). HFCs don't kill you or the environment as much and will probably pass emissions if you get a good one. You get decent power gains too. A trackpipe will show bigger gains, be loud as motherfrakingheck, will definitely fail emissions, and will destroy the world for your children.
Thank you! I was reading this thread thinking, "I have no idea where to start correcting people..." haha

Quote:
Originally Posted by fatgroundhog View Post
Are the exhaust manifolds and cats in the NA Subarus restrictive? Can't always assume that a car needs exhaust work at these points (though it depends on where in the power band you want to improve). Some cars in fact pick up power changing out mufflers since that's where the bottle neck is. I don't know about NA Subarus though...
Yes the mannifolds and cats are restrictive. Replacing these is where most of the gains come from. I put on borla replicas and a stromung trackpipe while keeping the stock catback, and gained a decent amount of power. Replacing the stock catback with a stromung sounded awesome, and gave me just a little bit more power. I had to accelerate up a hill i drove a lot before to notice the difference.
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