Exhaust question

:?: For the life of me, I have not been able to locate the photo from the Legacy brochure, showing engine, exhaust and drivetrain only. If anyone wants to post a link to this picture, it will better illustrate my question. Following the exhaust back from the engine, you see two cats located near the transmission. A bit further back, before the exhaust splits and goes to the mufflers, one sees what I assume to be a resonator. My question, for those who know more about exhaust requirements for turbo vehicles is this: What would be the benefits/detriments to removing the resonator and replacing it with an aftermarket muffler, then simply replacing all piping from there back (including the two OEM mufflers at the back of the car) and replacing them with straight pipes? A visual example would be something like what is seen on the current generation Mustang GT. Something like this photo, but with one muffler instead of two. [img]http://www.pacesetterexhaust.com/images/mustang_tfx.jpg[/img]

[img]http://www.subaru.co.jp/legacy/b4/04/imgs/photo_pack1.jpg[/img] I'm not sure how feasible that may happen to be considering you can see that resonator is wrapped around the driveshaft in a way already. Not all that much space to work with for a decently quieting exhaust. That's part of the reason to have two back boxes. Another: [img]http://www.subaru.co.jp/legacy/b4/04/imgs/top_photo_41.jpg[/img]

Well, remove the resonator and you'll change the tone of the car, likely for the worst. When the big exhaust went on my previous car, they put a resonator in after the sport cat, and it made a difference over other systems in terms of noise quality and joy of driving. Exhaust systems/tuning is a balance - there is levels to go to when you want the last 2hp, and then there are balances made when you simply want to go a bit faster/smoother. Unless you are in a racing fever, good tuning should get you to around 300hp/300tq with lots of overhead all around, semi-decent mileage and a lot of positive feedback. Cheers, Paul Hansen

I suppose the cheapest way to make a change would be simply to have different mufflers welded in there. Then again you could have the mufflers sectioned out, but not for me- my WRX already sets off car alarms driving by :lol:

I'm looking forward to AVO's solution pending the cost. I believe they are looking for an excellent flow but with a rather quiet volume as many Leg owners would desire. Stock look, better flow= better sleeper ;)

AVO??? Link??? :?:

It's in the works so I'm told, so no link.

No link for j00!!11 :lol: I'd like to see what the AVO solution is too- it'll be very interesting to see the various solutions tuners come up with for this car.

As I understand it, the turbo itself has a natural deadening affect on the exhaust tone. It is this attribute which allows the SRT-4 to actually come from the factory with no muffler per se. From personal experience, I ran a single Dynomax muffler with no resonator on my Prelude. The tone was nice, yet not overbearing, and I noticed a marked improvement in gas mileage and butt dyno.

Would the 4 pipe tip of the STi version give better flow and better sound i wonder?

I'm going to say without other modifications, that should be mostly a sound and look sort of thing. Those things are EXPENSIVE too, just for those two, but you're paying a lot for the name.

Is the GT factory exhaust constructed of stainless steel?

Parts of it, just don't know how much.

When I was at the dealer they had a bunch of them on the truck and I could see from underneath- it looked like the midpipe was steel, up to the part where it splits into two mufflers- that looked like stainless.

Here'smy vote: 1. 2.5" Stainless from Catback 2. Split at the Axel to 2.25" Stainless 3. 2 Borla Mufflers 4. Stock Tips! This combo would add the best power by alleviating the resonator, good low growl with the mufflers and a stock look with the tips! From my exhaust experience (I will not go into that here)........the 2.5" pipe will be great for the turbo or the NA, of course if you have the turbo you want to keep a 3" pipe from the cat FORWARD to the engine. However you do it, the EXHAUST MOD should be your first investment! ~AdrenalineGT 8)

Adrenaline, gotta make sure you can push the same volume, area/volume in a cylinder can be very deceiving. 2.5 to 3" to the split and whatever the volumetric difference may be for a split is what I'd suggest. I think a good ECU tune should be the first investment. ;)

ECU tune sounds like the best starting point, and if it's anything like the WRX, it should yield some grest results!

That's why I recommend it. Just use the recommended range of parts per stage for the ECU and you're golden. :D

It'll probably be a while before any tuners offer reflashes now. The only problem I forsee is the wait!

I can wait til next year for that.

[quote name='AdrenalineGT']Here'smy vote: 1. 2.5" Stainless from Catback 2. Split at the Axel to 2.25" Stainless 3. 2 Borla Mufflers 4. Stock Tips! This combo would add the best power by alleviating the resonator, good low growl with the mufflers and a stock look with the tips! From my exhaust experience (I will not go into that here)........the 2.5" pipe will be great for the turbo or the NA, of course if you have the turbo you want to keep a 3" pipe from the cat FORWARD to the engine. However you do it, the EXHAUST MOD should be your first investment! ~AdrenalineGT 8)[/quote] Borla is droning and ofter times louder than hell! At least that's been my experience in the past. It really all depends what you want though. I don't know what I am going to do with my exhaust

Would be nice if there is a nice Bosal/SPT setup. I have heard from several that the system performs, and is rather quiet additional to it being very cost effective, full stainless, and looking fairly stock. $375-450 is common for that setup, full 3" stainless cat-back! Would be nice to see a Leggy GT unit in the $600-700 range with the same characteristics. :cool:

Borla Hush for the WRX is quite mild actually Dr. Zevil. I agree on a Bosal system. SubyDude has an entire Turbo back exhaustfor 650 shipped! It includes the Helix downpipe (with integrated midpipe) and the Bosal catback system (3" all the way through, mind you). We definately need something like that for the Legacy!

I dunno man- I'm leaving the cats in this car- the WRX is too loud.

[quote name='jedimaster']I dunno man- I'm leaving the cats in this car- the WRX is too loud.[/quote] Quiet old man! :P :lol: