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BoostCruising _ Car Help & Advice _ Exhaust for N/A Subaru :P

Posted by: Mcleod Oct 18 2002, 11:53 PM

I'm pondering over whether to start saving for an exhaust or not tongue.gif



I guess it would be really nice to get that subi boxer engine purr coming from the engine, but I also don't want something particularly loud.. just something I can hear I guess without it being overbearing..



With that in mind, I'm very cautious to get a larger exhaust with the fear I'd be spending my money on something I'm not going to like..



Anyone else with NA Subi's? What have you got and how about the results?

Posted by: TwinCam16 Oct 19 2002, 02:19 AM

Yes it will make the sweet sound.



now there is 2 ways to approach it.



1 -if you only want sound and dont give a toss bout increasing power, just change the muff to a sports type. This will make the note u want



2 -Replace the system from the cat back with a quality 2.25" system. do go any larger! its n/a not turbo, u need some form of back preasure 8)



I have had evry car i own done at Right Price Exhausts at Moss st, Slacks Creek. (just off the pacific highways near sprinwood maccas) with the exception of the turbo manfold wich is being done by exotic exhausts....



If you keep the pipe at a sensible size and get a QUALITY muff, u wont be dsapointd

Posted by: Hoon Oct 19 2002, 07:39 AM

I'd like to say that the number 1 point that TwinCAm said isn't a good idea. I did that to mum's (hehehe!!!) liberty wagon, and it sounded like the biggest peice of shit over 3 grand. However, idling around, and the burble gave it some massive headstares, and while my mum isn't one for exagurating, apparently, she was getting races!



Now, McLeod, you know and I know, and everyone here knows, you get what you pay for. I'd suggest the following:



Cat-back zorst, including a high-flow cat ($300) in 2.25 inch (I agree with that size, maybe 2.5?) all in mandrel bends. Hey, costs more, yes, does flow more, yes, so you might as well do it right the first time hey? Piping would be about $120. then we get to a sporty muff...don't go half assed, get a stainless steel quality muff. This should cost you about another $300 tops. Then we move onto the resonator. I reckon scoobies sound pure horn when they have a nice deep drone from the res. That'd cost ya $150..I'd suggest a Mangaflow job. They flow very nicely.



Now, if you don't have a zorst shop yet in mind, I'd suggest you take a trip down the coast, and see Michael at High Performance Exhausts at Ashmore, near that big Ford & Toyota joint. With his prices, you'll be impressed, and his work is excellent. For example, my zorst, a 3 inch from extractors, mandrel bend, all stainless, stainless muff, Magnaflow res was a total of $400. And it's a cherry system.

Posted by: Mcleod Oct 19 2002, 12:15 PM

I've had a look at a few of the goodies at mrtrally.com biggrin.gif



They have one too many goodies for Subi's! I was quoted a full system usually used on the 2.5l liberty (I think) for like $900, stainless, from engine back.. but I dunno.. I'd like a bit more power, as does everyone, but I also kinda like it to be quiet alot of the time.. wierd I know tongue.gif

Posted by: TwinCam16 Oct 19 2002, 03:03 PM

900 bucks for a full stainless system is good Mcleod, especially from the engine back...



Id be looking seriously at that

Posted by: Enema Oct 19 2002, 03:45 PM

*technically* all back pressure is the enemy of performance on N/A and turbo cars...



The reason N/A cars need smaller exhausts than turbo cars is because they don't move enough exhaust gas...



When the pulses of gas leave the engine they have to travel the full length of the exhaust and out, as quickly and straightly as possible for maximum power...



Air expands outwards before expands lengthways... what this means is that it will expand to fill the exhaust before it expands to exit the exhaust. So, on cars with an exhaust too big for them, the exhaust gas hasn't exited yet because there's too much room to fill up... so each new pulse from the engine sends a blob of gas down the pipe and bangs into the last pulse which hasn't been able to escape yet...



as each new pulse hits the last one, the exhaust actually acts like an open bottle... with the exhaust gas trickling over the lip (tailpipe) as the bottle gets full... with all this "back pressure" in the pipe... it restricts the exhaust from opening properly.. and you find that your car is mixing fuel with air you've already exploded... i.e. not very rich in o2.



In summary... big exhaust on N/A car is bad... big exhaust on turbo car is bad unless it's sized properly... and finally, back pressure is nobody's friend.

Posted by: Anonymous Oct 19 2002, 08:40 PM

I agree, the stainless system does sound good. The only issue I can think of is that with the stainless systems, it often creates more noise. But the stainless system will most probably be the best. A idea you might like to think about is heat treating the entire exhaust system, this will reduce engine bay temp and also reduce noise. I would do this as well as add a resinator like suggested before. When you do get the exhaust done, and you drive away, it will sound a little louder than it will in a few days/weeks. NO, NO, NO this is not because you have got used to the throbbing sound, it just takes a while to where it in. After a few weeks, if it is still too loud, you can put a hot dogs in the exhaust (no not the ones you eat, hahaha), this will also reduce the noise. Anyway goodluck.

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