SR20 exhaust setup. Professional opinions (maybe some people's .02¢) welcomed.

[mr.nismo.]

Hey everyone. Just looking for opinions on a setup I'm thinking of. Prev setup was full three inch all the way through. Mil spec 100 cell cat> vibrant ultra quiet resonator > tanabe super medallion catback. The car was pretty loud and I always had the silencer in (dd). I definitely noticed a restriction when having it in, and I would like to keep it out this time.

For a new setup, I'd have the mil spec cat moved up (maybe 8 inches ahead of oem cat location) > 200 cell high flow magnaflow cat (in oem location) > y-pipe into a dual inlet single outlet magnaflow straight through 5x8 oval muffler in oem pre axle muffler Location > tanabe muffler. I feel (please someone correct me if I'm wrong) that having the dual inlet muffler going back to single will force some sound to be absorbed into the packing in it and still stay straight through. I'd like to have the magnaflow cat to help more with the smell, but still be able to quickly swap it for track days for a test pipe. Again I'm not a sound engineer or anything, so I could be totally wrong in my theory. I've read up on some exhaust loops (once that re-enter the stream and others that stop) but nothing SR specific nor about going y pipe into the muffler and back to single. I'd love to hear some insight and maybe someones own experience. Thanks in advance!

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[TheRealSy90]

So you want two catalytic converters, and two mufflers?

Yeah you're going to have tons of restriction dude.

Also idk how your previous setup was remotely loud, maybe California things lol.

[afishysilvia]

I would think with a muffler and cat should be enough to silence the car down. I run my engine no cat with just a bullet muffler and dual out muffler 3" piping the whole way. Sounds quiet when I want and like a bat out of hell when Im on it.

Cali is great man...just gotta find ways around it.

[RalliartRsX]

Add a bigger/different muffler, bump up the CAT size and keep the vibrant (its one of the quietest on the market)

If I am thinking right (cant find pics of the super medlian apart from cannon style mufflers), the main source of your sound is that Super medalian (if it is indeed a canister). Canister are just inherently loud with no sound absorbing properties what so ever.

If it is indeed a canister, ditch it immediately and go with a Noir, or Vibrant ultra quiet/stealth muffler

[tuzzio]

also, if I recall from previous research on my own, you want the mufflers as close to the end of the exhaust as possible, as the sound travels further it bounces around it gets louder.

[mr.nismo.]

Originally Posted by TheRealSy90

So you want two catalytic converters, and two mufflers?

Yeah you're going to have tons of restriction dude.

Also idk how your previous setup was remotely loud, maybe California things lol.

Its 300 cells worth of catalytic converter yes, but both mufflers are straight through. However yes, California things for sure. It's nice when behind pulled over and an officer looks for a cat and mufflers and is satisfied.

Originally Posted by afishysilvia

I would think with a muffler and cat should be enough to silence the car down. I run my engine no cat with just a bullet muffler and dual out muffler 3" piping the whole way. Sounds quiet when I want and like a bat out of hell when Im on it.

Cali is great man...just gotta find ways around it.

The mil spec and vibrant res helped, but not enough. So far only the silencer did it. It's not terrible to me, but too loud for CA "standards".

Originally Posted by RalliartRsX

Add a bigger/different muffler, bump up the CAT size and keep the vibrant (its one of the quietest on the market)

If I am thinking right (cant find pics of the super medlian apart from cannon style mufflers), the main source of your sound is that Super medalian (if it is indeed a canister). Canister are just inherently loud with no sound absorbing properties what so ever.

If it is indeed a canister, ditch it immediately and go with a Noir, or Vibrant ultra quiet/stealth muffler

Well I'm stuck with the mil spec cat ( it's awesome, just want to fume down a bit more) but 300 cells is right where I want it, otherwise I'm close to an actual California compliant cat. The muffler is cannon style, but it's not a giant wide can or anything. I attached a pic of the actual catback. I wanted to go bigger muffler, but am restricted room wise under the chassis in the oem location (I measured around the area where it sits ).

Originally Posted by tuzzio

also, if I recall from previous research on my own, you want the mufflers as close to the end of the exhaust as possible, as the sound travels further it bounces around it gets louder.

Agreed, that's why I was wanting to stick a muffler in the oem location. I was hoping that as sound traveled through that v and the internal v in the muffler, it would bounce and abosrb sound while not resistricing flow.




As a side note, thank you everyone that has responded.

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[harlockssx]

HKS Hi-Power exhaust is one of the more quiet yet unrestrictive off the shelf systems. Typically, the larger the muffler case, the more quiet it will be, due to being able to pack in more sound deadening material. As long as what you're using has a straight through (not chambered) design, there should be no loss of power. I had to use silencers before, when I was living in Japan...switching to an HKS Hi-Power solved most of my noise issues with the Military and Japanese Police. There are newer mufflers like Varex that can be electronically controlled for noise, like EVCs do inline.

[mr.nismo.]

Originally Posted by harlockssx

HKS Hi-Power exhaust is one of the more quiet yet unrestrictive off the shelf systems. Typically, the larger the muffler case, the more quiet it will be, due to being able to pack in more sound deadening material. As long as what you're using has a straight through (not chambered) design, there should be no loss of power. I had to use silencers before, when I was living in Japan...switching to an HKS Hi-Power solved most of my noise issues with the Military and Japanese Police. There are newer mufflers like Varex that can be electronically controlled for noise, like EVCs do inline.

It'd be a nice switch, but PO of my exhaust already hacked it, so I already invested a bit on this one. And yes I had read on that and wanted to get a big case muffler, but then got a reality check of what could actually fit there when I measured (hence the v setup theory haha) but both mufflers will still be straight through. Only the two cats totaling 300 cells

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[RalliartRsX]

Get rid of the cannon. That is 90% of your sounds problems right there.

[carcrazee]

hks hi power, my car is so quiet and it actually felt like I free'd up some power(s13w/s14sr20det)

[RalliartRsX]

The Hi Power comes with a monster Resonator prior to the Cannon mind you, hence why it is so quiet to begin with.

[mr.nismo.]

The hi power muffler is around the same size as what I already have. This is what I meant by I want to throw something in front of it. I'm not super keen on buying another 400$+ catback when I can put a muffler on the one I already have. On top of it, trying to sell a cut catback I already have. That's why I'm asking if anyone has done this before?

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[harlockssx]

You realize you can just buy the muffler and add it to your existing catback...? I had to do that on my IS300 with a 3" Japanese exhaust system that was just ear bleeding loud. Ordered an HKS Hi-Power universal muffler in the diameter I wanted, in the length I wanted from TH Motorsports. Trust me, pretty much any muffler that is short enough to replace your existing one will fit...IDK why you're worried about case diameter, because some of the JASMA muffler cases are HUGE.

[S14DB]

Yeah, you have no resonator on that kit. Add a 3" muffler to it. Oval 3"-3" single in-out. That y is just going to add turbulence

[mr.nismo.]

I did see a borla 3 inch in/out that's offset/center. It should fit in place of the y/dual inlet idea (plus its cheaper). I did see a lot of reviews that the pro xs line is very quiet. Coupled with the second cat, it should pipe down the exhaust (see my pun?) while not having the silencer in.

[feito]

Fwiw, my apexi N1 is pretty quiet. rb25 with a gt30, custom 3" downpipe straight to the exhaust (no cat delete). I believe the exhaust diameter is a bit bigger than 3", 85mm I think, and it has a big pre-muffler resonator, right next to the driveshaft. It's reasonably quiet, especially when you're driving it easy.