moderate mods to an '03 Sedan

[grumpyhessian]

Hi all,

My Subaru is an '03 SE sedan A/T, but not a GT. I'd like to get a dual exhaust system for it, and as far as I can tell, there's no difference in the underside of the GT vs. the non-GT. I want to get maximum exhaust flow without a lot of obnoxious noise. Where I live that just makes you a cop magnet. I'd also like to put a much higher flow intake plenum/filter on this engine (EJ25). I'm not looking to make too many mods since this car is my daily driver, but given the weight of the vehicle, it seems a bit underpowered at 165hp. I would think that a little more hp might actually increase mileage since the engine would be operating more efficiently. This is assuming, of course, that I'm not too much of a lead foot.

Any ideas?

[rougeben83]

The GT doesnt have a "dual exhaust" either.

[grumpyhessian]

Right, I get that. But everything that I've looked up in the aftermarket world lists dual exhaust, (that is, both exhaust banks into one high flow converter) then out of the converter back to dual pipes, is listed for a GT. Nothing listed for any non-GT cars. My only question was that if I order aftermarket "dual" exhaust for my car, even though it's listed for a GT, it should fit, right?

[BE-Fresh]

The dual exhaust systems you are referring to are for the BL/BP chassis (2005-2009), which most likely will not fit the BE chassis

[Reason]

It is for the 05+ LGT and wont fir your 03. Your mods are very limited for "bolt ons". As for your "165hp" That is at the crank, you have a AWD car, theres more drivetrain loss which I figure to be AROUND 33% loss.

[grumpyhessian]

Well, there's a custom exhaust shop down the street from my house, I guess I could let them have a look. They might be able to build me a "dual" exhaust cheaper than I could buy a pre-made. Yes, I know the 165hp is at the crank, and I also know my car weighs in at @ 4000lbs. Like I said, I used to work for Subaru for 3 years as a technician, 6 years total "in the business", 5 ASE certs, a mobile AC cert, and a VA state inspection license; not to mention all the other technical schooling I've had through other employers. Although, I've actually been working on cars for, hmmm, about 22 years. Anyway, who makes a good high-flow, QUIET muffler? Who makes a high-flow catalytic converter? If I'm going to get my own custom system built, might as well not have the stock converter choking the thing.

[Reason]

Of course an exhaust sho can make you a system. And yes it cost you $1,000 to make your "dual" exhaust and it would be cheaper than the market.... because nobody makes one for it. Off hand for the BE I only remember seeing Stromung and JIC making bolt on cat backs.

Stromung and random technology makes bolt on cats. But if you are going to get a custom cat back made you mind aswell do the cat section too because it will be cheaper.

[grumpyhessian]

I just checked Borla's site, and they actually make a header all the way up to the cat for my car. Then the only issues would be finding the right cat and cat-back system, oh, and some decent quiet mufflers. I'm thinking I could just make my own intake plenum and put a K&N filter in the stock filter box. Whatcha' think?

[Reason]

Yes those Borla headers fit on many different models for Subaru. I was talking about the mid pipe and axle back section.

[httrdd]

I have a dual exhaust thread that has some really nice pics of widebodies with dual/dual tips.

[ouch1011]

Dual exhaust isn't going to flow any better than a properly sized single exhaust. 2" for most stock or lightly modified EJ25s, 2.25" max for moderately modified N/A EJ25s. It will also add unnecessary weight. If you want it for looks, thats a different story.

The Borla header is unequal length versus the stock equal length setup. You will likely lose power with this setup, possibly break even on a good day. If you want a header, find an equal length header like the OBX.

There isn't much power to be made from bolt-ons for N/A Subarus.

[httrdd]

viewtopic.php?f=71&t=16668&hilit=dual+exhaust (http://www.sl-i.net/FORUM/viewtopic.php?f=71&t=16668&hilit=dual+exhaust)

[grumpyhessian]

Looks aren't that important to me. I try to keep my car clean, but that's about it. I understand what you mean about the unequal length in the header. When I was cutting my teeth on the old V8 muscle cars we would put a crossover pipe in just aft of the header collectors; made a big difference. So, maybe stick to a high flow cat-back single pipe set up, and increase intake flow? I do know that a stock catalytic converter, at least on most cars, is a real choke point for the exhaust system. It was explained to me years ago that an engine is basically an air pump. The more air you can move through it, the faster it will spin (provided you can mix enough fuel with that air!).

[rougeben83]

just stick to 2.25" diameter, its more than plenty for a relatively stock legacy.