Jump to content
LegacyGT.com

Designing a QUIET, Straight Through Catback Exhaust!


Recommended Posts

  • Replies 68
  • Created
  • Last Reply
I wrote that somewhat incorrectly. However, it would be cool to really truly understand the environment of engine exhaust, and I feel my bits and pieces are not enough.
[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
Link to comment
Share on other sites

Pains me to say it (not really) but Rao was right, I should have put on stock cans :(

 

Fantastic learning experience though, seriously. The Borla trifecta is quieter than the AutoSpeed for sure. It's exactly what I thought I wanted. But now I have it and I really don't care for it. It produces a very low deep smooth subtle sound that is ever present at cruise and idle, more obvious though with more speed, of course. It is not drone, not by Subaru standards anyways. To my ears, it is bland and is completely void of personality, and that's the problem. AutoSpeed was cool because, though louder, you could hear it, and enjoy its character. As a stage 0/1 catback, it sounded beastly, in the best possible way. This 3x Borla is quieter, but has NO character, at least to me. And now I realize, my lesson: have a clear objective, and be honest with yourself. My primary goal, superficially, ended up being a straight-through design. Well, not really. If I had listened to my heart, the goal has been and continues to be to enjoy the car. The definition of this is ever changing. But today, now, I want this thing QUIET! Stock muffler quiet. Quieter. There is still a bit of an exhaust rumble, but if it can't be enjoyed (and by my tastes it can't) then better to have nothing than something unpleasant, at least when it comes to sound.

 

If a stock exhaust crosses my path, I'm taking it.

 

Additional notes:

The Borla muffler pair in the rear is not tall enough, and thus does not do enough to reduce sound level. It looked better on paper, but in life you can see the oval is more flattish than rectangular, so there is wasted suppression potential. As such, ITSME has the same setup but with MagnaFlow mufflers in rear, and now I am a MagnaFlow FAN, just because of their cubic volume.

 

I'm glad I went with exhaust clamps so I can easily swap to a different muffler (if need be), but the downside is as a byproduct of design, they leak a little. This may be contributing to the low rumble.

[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
Link to comment
Share on other sites

Video?

 

Yes but it's iPhone3GS, so all you can hear is what sounds like ambient machine noise in the background, and my voice. You can't even discern between side and back of vehicle noise, though in person it's obvious.

[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
Link to comment
Share on other sites

Shocking :lol:

 

I was thinking to myself, "Wish Rao would post more of his words of wisdom." Then looked at your post count again :)

 

I'll dig through the archives.

[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
Link to comment
Share on other sites

My prediction, for the record, is I'm going to hear more wind/road/tire noise on the highway at 70mph / 3000+rpm cruise, than engine noise (thanks mostly to the EL header on top of this system). My main point of reference is ITSME, who has a very similar setup except UEL headers, and has no highway drone, and a quiet car relatively speaking. Usually my predictions are all wrong, but lets see if I can't get it right for once :lol:

 

Well I got something right.

[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
Link to comment
Share on other sites

I had my new Y pipe out to work on the suspension. Looked into it and saw DAYLIGHT! So I'm not necessarily an idiot, and my research-based predictions may prove to be wonderfully correct, that my new exhaust will be pretty darn quiet without Hogzaust-ing. Actually found 2 leaks before the rear mufflers, and both are pretty considerable. Once those are fixed, we'll see how loud it is :) This is excellent news! Love exhaust leak testing via Sea Foam smoke :)
[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
Link to comment
Share on other sites

I'm just gonna sit back and when you find something that you like, chances are I'll probably like it too LOL

 

I don't mind my SPTv2... but I'm thinking about chopping up the midpipe and installing a 3rd muffler... later down the road I'll chop off the y-pipe and replace that and the cans

Link to comment
Share on other sites

As long as you don't mind a reduction in ground clearance under the middle of the car, the Borla Sportsman XR-1 in the dimensions posted in this thread fits with lateral room to spare. There are two other examples (Gotsugg and Itsme) running it in 3", demonstrating how much it cuts drone and overall noise. If your midpipe is smaller than 3", it will be a little quieter still. Based on what I've researched and experienced, my opinion is that the hard part is not finding quiet or nice-sounding cans, but instead is getting the pipe routing done inexpensively while retaining quality and fitment of the pipe sections. The stock catback deserves a good look before you jump into what I've done, if your goal is indeed a mild noise level. More to come later. I am in no hurry.
[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
Link to comment
Share on other sites

My catback should be done soon! I expect a nice, mellow tone that won't piss off a wife.
[URL="http://legacygt.com/forums/showthread.php/proper-flip-key-interesti-159894.html"]Flip Key Development Thread[/URL] "Genius may have its limitations, but stupidity is not thus handicapped." - E. Hubbard
Link to comment
Share on other sites

I'm just gonna sit back and when you find something that you like, chances are I'll probably like it too LOL

 

I don't mind my SPTv2... but I'm thinking about chopping up the midpipe and installing a 3rd muffler... later down the road I'll chop off the y-pipe and replace that and the cans

 

Why not try out a set of ELH's. They're supposed to reduce the noise a little while increasing torque and hp plus moving the curve to the left (depending on who you believe). I'm looking at either the GT Spec ELH's for those reasons or the GrimmSpeed PNP manifolds and crossover pipe (just for moving the curve to the left). I've changed my mind on this 60 times in the last month though.....:spin:

Link to comment
Share on other sites

  • 3 months later...
  • 3 years later...

Necro bump....

 

Any updates?

 

I'm in the same boat.

 

I have 2 pairs of OEM mufflers, they all rattle under light load.

2 ebay cans packed, but the tips are hallow, extremely loud.

2 SPT cans, manageable, but needs to be a bit quieter.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.




×
×
  • Create New...

Important Information

Terms of Use