Like the title says, when I get an exhaust I definitely don't want to end up in the position it seems like so many tC owners that HAVE aftermarket exhausts are in (ending up with that annoying rasp that will drive you crazy just on the commute to work!! lol). The only other engine mods I'll be doing for now will be a CAI so my car can breathe! I've been listening to sound clips and from what I can tell (without hearing them in person) the ones that I think give that sweet low tone that I'm looking for are either the HKS cat-back system OR( what I'm really leaning toward) the Megan Drift Spec cat-back system. I know.. I know.. angled out, blah, blah blah, BUT it seems like that is the nicest sounding exhuast I've heard on the tC yet and would give a few extra HP. I love the sound of the WRX, and the Drift Spec on the tC is a pretty darn good imitation but before I go spend a bunch of $$ on something I might regret.... Ideas? Opinions?

 

the rasp only happens most of the time when you add a header because that is what happen to me i have a short ram intake and then got a axleback exhaust and it sounded deep and then i was like hmmmmm more horse power lets add an header and bam raspy sound, then i was told to get rid of it buy welding on an resonator and or a high flow cat.

 

I have the Megan Racing header, custom 2.5" s-pipe, 2.5" mid pipe and and universal magnaflow exhaust, I have no rasp, thats because I had the shop add an aftermarket cat and a 40" resonator, man this thing is huge, but it was worth it, I love the sound I'm getting out of my system now, it almost sounds like a V6, I'll try to get some audio clips up soon, I was planning on doing it anyways.

 

whoa, 40 inch resonator...................jesus................pics please

 

Sure...tomorrow, yeah...its huge, when I saw it I was like, what truck did you get this from? he he, but this guy knows his stuff when it comes to custom exhaust systems, so I trusted him and like I said...it paid off.

 

The WRX engine is absolutely delicious.

 

out of curiosity does that big of a resonator or any resonator restrict flow any, it seems that it would.

 

if it does restrict... it would be VERY minimal. resonators are a straight through design. think of it as a pipe within a pipe, and the inner pipe is perforated.

 

Yeah it was the perforation of the inner pipe that made me think a little as it would cause turbulence and thus restricting it a little but your prob. right it wouldn't do it much.

 

think of newton's law or something like that... objects will continue in a straight line unless something acts on them. if exhaust gases are flowing straight down a pipe, and enter a resonator, even if that pipe is perforated, there are no other forces acting on the exhuast gases to make them want to deviate from the straight path that its already taking and go through the perforations. the perforations are there, but have very little effect on exhaust gases.

the only time i could see the perforations causing some turbulence is in boosted applications where the exhaust is semi-pressurized and wants to expand. Other than that though...

 

well newtons law does apply but at the atomic level only because gasses are un-uniform and molecules collide at random with themselves and the walls of the container (wall of exhaust) so molecules would be going through the preforation and becuase of it cause more colisions with the molecules heading the right direction thus slowing it down. ok enough science and sorry if I took the thread and sounded like a butt i was just wondering if anyone else noticed this idea

 

megan drift spec 2.5" with 2.5" midpipe and resonator, 2.5" s-pipe and 2.5" turbo downpipe

deep low tone with a WOOOSH every now and then

 

turbo's dont count... the turbo is a humongous muffling device.

that's how the srt-4 could get away w/o a muffler from the factory

 

tofuman, hks is a axleback, try greddy evo2 or sp2 with deep tones......and if you add a header to the sp2 it still sounds great with very very little rasp, but for the evo2 its over....

 

actually, it would be bermoulli's principle at work along the entire length of the exhaust - just had to put that in. Also, turbulent flow wont cause any exhaust restriction, as that is almost solely influenced by the diameter of the pipe, and obstructions along the way, like cats & mufflers (which effectively reduce the diameter of said pipe).

 

doesn't bermoulli relate pressure and velocity and not turbulent flow? and there are different types of restriction, for instance friction restricts flow which I think resonators act as (since it is a obstruction along the way).

 

new thread for you science nerds

 

but but... fine

 

lol

 

ive heard some HKS's get raspy at high RPM's even without a header. never had that with my TRD...it sounds mean with my fujita CAI.