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2009 OB 2.5i SE 4EAT
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131 Posts
Discussion Starter #1
High everyone,

Ever since I got my N/A 2.5 tuned by XRT (Edward Millington, god of Subaru e-Tuning) I noticed that way my motor runs sounds freaking AMAZING, but 2 problems with the stock exhaust: 1) it's actually holding back the tune, causing fuel to go unburnt because it can't evacuate fast enough, so we had to back the tune off a little and 2) IT'S TOO QUIET! I want it to POLITELY rumble along at low and mid RPMs and start to make some real noise above 4000.
>:)

I posed a couple scenarios for a custom exhaust, and Ed's recommendation was "the design is yours, just use magnaflow". Roger that, Ed! I've heard plenty of catback magnaflow setups that sound gorgeous but they don't make one for my car. However DIYing it is not actually super expensive. It's possibly cheaper, particularly if...

I found a local guy who's ASE, likes to weld, has access to a pro shop lift and is willing to put it together for me on the cheap. I just need to supply all the bits.

So that's what this thread is about, my N/A exhaust journey. A couple guiding points:

-This could take a while. I'm buying the bits one at a time, once I'm certain which ones I need.
-Stainless steel. I live in the northeast, why mess around?
-Stock equal length headers. The catalytic converter is integrated. What can ya do. I need it to pass emissions, yes people have changed them and maintained passing emissions, but it's a whole thing, look it up yourself, even though UELs might sound cool, I don't want to be melting nearby lines or swapping in a WRX oil pan etc. I don't want this post to turn into a discussion about this. To stay on budget, and ensure this daily driver will easily pass inspections, this project is going to be strictly cat-back.
-Single exhaust conversion for weight reduction, cost reduction and practicality. Exit muffler on the passenger side for balance.
-2.25" piping all the way. This matches the largest diameter of stock piping being used, the header-cat flange size, and should be plenty for a car that will always be N/A (with no exhaust tubing reductions).
-A round-spun high flow cat. Subaru uses one of these in the mid-pipe and magnaflow makes them so why not. Essentially you could leave the stock pipe and cat and make this exhaust midpipe-back, but I'm not sure the condition or flow-ability of my stock pipe. Plus it's rusty fugly. Get it out. A straight pipe should be fine too, but I'm not going for loudness, don't need maximum flow. And again, want to be absolutely sure of passing emissions.
-A straight-through muffler acting as the resonator. When I replaced the rusty y-pipe, I bought aftermarket OEM. The Y-joint on Bosal's replacement was far superior to the stock (and Wagner) design. However, the "resonator" Bosal includes is basically a cherry bomb glass pack. It sounds awful. I would rather do a straight-through muffler here which will act as a superior resonator. It will also take up the space of the stock resonator, which helps shield the driveshaft from road debris. For whatever that's worth.
- A Magnaflow XL baffled muffler as the exit muffler. The round spun cat and the XL muffler baffles are really the only things providing any flow restriction in this setup.
- A turn-down tip because I like the way they look and it can fit the stock bumper without any modification. I'm good with stainless steel. I don't like chrome and titanium, or anything that looks fake and not the true diameter of the exhaust.

Next up I'm going to have to find and post all the part numbers for each of the important bits. There also will probably need to be a flex joint. I won't mind posting the part numbers for the same setup with a 2.5" in case anyone wants to go that route. I considered it, but the 2.25" stuff is a little cheaper, and again, no boost here. Should be more than sufficient.

Anyone care to check my logic, or add anything I should cover?
 

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Registered
'08 2.5l MT
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64 Posts
It sounds like the nameless turn down axle back with the 5" mufflers would do the trick for you. i'm curious to know what you ended up going with
 

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2005 Outback Wagon 3.0 L.L. Bean
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838 Posts
Substitute a universal glasspack for the straight through muffler.
 
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