Free flowing silent exhaust...possible?

[SVXMAN2001]

Subject pretty much says it all, what are my options for creating a more efficient, more free flowing exhaust, that is as quiet as the stock set up if not quieter? Any ideas of what components would achieve this?

[Crazy_pilot]

I've been working toward putting a system together which *should* fit that bill pretty closely. I haven't bought any parts or started making anything yet, but the design is pretty much solidified. It basically mirrors the stock system in terms of layout, but with high flow components.

2" piping off the stock headers to 2 Magnaflow mini-cats (http://store.summitracing.com/partdetail.asp?part=MPE-50004) (P/N 50004). Then more 2" into a Magnaflow 2-1 cat (http://store.summitracing.com/partdetail.asp?part=MPE-94007CA) (P/N 94007). This goes into 2.5" tubing to a Magnaflow resonator (http://store.summitracing.com/partdetail.asp?part=MPE-14416), then 2.5" to behind the rear axle. This is where it gets a bit tricky. I want to do a sharp-ish bend after the diff to center the pipe, then fabricate a 1-2 y-pipe, reducing from 2.5" to 2", with 90° curves. This will go into two Borla turbo mufflers (http://store.summitracing.com/partdetail.asp?part=BOR-40651), and then out through a good set of tips.

Everything ahead of the rear axle will be similar to the stock SVX setup, the final mufflers will resemble the Flatt Racing exhaust.

http://us.st12.yimg.com/us.st.yimg.com/I/svx-motorsport-accessories_2007_7567745

I think with the extreme use of things in the system (6 components compared to one cat and one giant tin can muffler on your suped up STi's out there) it should be a very low volume, but should still flow very well.

Also, I priced out the whole system through a local parts guy who offers deals to the local Subie club. I can have all the cats, resonators, and mufflers for about $650.

If you've ever seen the SVX's stock muffler apart, it's a convaluted mess of big pipes. I'd say that's where 80% of our exhaust restrictions are.

[SVXMAN2001]

interesting...let us know how the progress goes.

[TomsSVX]

I just finished up a new exhaust. Has a great tone, ever so slightly louder than stock and flows very well.

Stock head pipes & pre-cats
2-1 Magnaflow highflow cat
stock resonator tubing
Back to a transverse polished Bullet 1-2 muffler
Out through magnaflow tips...

Will post pics in a little while. This exhaust could be made louder with the removal of the pre-cats and possibly the resonator, but I don't think thats what the owner wants. Right now it just sounds like a dream and looks great too!

Tom

[SVXMAN2001]

Tom, anyway you would be able to get a soundclip of it?

[processengr]

Tom, anyway you would be able to get a soundclip of it?
plus one!;)

[LetItSnow]

I never understood exhaust soundclips. Sure enough, the volume and true sound can't be replicated by my crummy laptop.

Anyway, flowy + quiet FTW.

[TomsSVX]

i will try and get one today...

Tom

[redlinedeath]

this may just be looked at as a stupid answer, but if you were to get a good microphone, and rig it somehow, so it picks up your exhaust tone, send it to sound editing software on a laptop that has lightning fast processing speed, invert thesoundwaves in real time, and play back the new inverted waves simotaneously witht he actual exhaust, it should theoretically eliminate the sound... completely. but as you cant have perfect real time recording/playback, it would still have a very very light sound. i know, stupid, but ive always found this concept intriguing. i may have the process wrong, but its something very similar... i wish i had large amounts of disposable income to try something like this... itd be fun!

and yeah, this process may not work in this application, but its still a pretty damn cool concept!

[Twinboosted]

If it's possible, I would go for true dual 2.5" exhaust all the way back. Resonate the mid pipes and the H-pipe as well. If you plan to keep the cats, those will help cutting the sound down but high flow cats are a must to keep the flow adequate. Having two resonators and a dual tip muffler with 2.5" piping on each side with an H pipe will flow way better and be very quiet as well.

[sicksubie]

That would be WAY to open for an N/A car. Also, if you run a true dual set up on a SVX you do not need an H pipe or any cross over for that matter....

[Twinboosted]

Bah.... Misconception. The H pipe would help with deadening the sound and help with the scavenging. It would not be "too open" either. Non turbo 300ZXs are quite often modified with 2.5" exhaust and a lot of them are also equipped aftermarket headers all of which improve performance with no down falls. The EG33 is similar to the VG30 and figuring the displacement and the engine characteristics, the dual 2.5" should suit the SVX well.

[sicksubie]

I dont think so..... Ask the Tom's though as they have had more exhausts than everyone else combined...

[TomsSVX]

A single 3" would outperform a dual 2.5 not to mention it would be lighter.

Tom