MY07/08 Sedan GT-B Stock or Tuned by STi exhaust (Cat back)

[cpitts]

Good luck man. I don't envy the noise the car will make with a hallowed out muffler.

It'll sound nice, trust me. Done this numerous times on WRX's with GREAT aural results. And no, there's no drone or excess noise as you're not changing the size of the resonant chambers or diameter of the exhaust tips.

While that theory is all and good, and you'll see a quicker response at the low end, I think the OEM diameter will act as a bottle neck for gains at the mid to high end, especially since it's a turbo.

I was able to achieve (easily) 165kW ATW (at AVO) with a WRX with nothing more than a gutted muffler and the remainder of the exhaust stock. The myth of a 3" exhaust is marketting up to a certain power level. The critical restrictions in airflow are more the chambers in the mufflers and resonators, not the pipe diameter. The next biggest restriction to more instant delivery of power is the dump pipe (the first 10-20cm after the turbo in reality) after which it's just airflow dynamics.

I'll keep the finer details (and dyno charts) of this argument to another thread. This is a thread about me trying to get some experimental mufflers!!!

c'mon guys! Surely there's some lying around somewhere????

[Arith]

If you can make it work, and work well, more power to ya! Good luck!

[GTSPECB STI]

Experimenting -> yes. (refer here for an example of what's gonna happen http://www.corptech.no-ip.org/doodads/htdocs/cars/MY05WRX_mod_gutmuffler.asp )

LOL I love the Ghetto zorst mod.

[cpitts]

Experimenting -> yes. (refer here for an example of what's gonna happen http://www.corptech.no-ip.org/doodads/htdocs/cars/MY05WRX_mod_gutmuffler.asp )

LOL I love the Ghetto zorst mod.

And what's even cooler is that it works! Total loss of 1kW @ 160kW ATW compared to no muffler at all, so not bad for backyarder action .

[gtspec]

oh so u done this mod already? any sound clips?

[cpitts]

Yep, that's my website!

Here's another directory with some pics of the after work and some MP3's of the results. You'll really need a set of headphones (or decent low freq PC speakers) to hear the extra throb.

http://www.corptech.no-ip.org/upload/2006-01-18%20WRX%20Modded%20Muffler/

The extra airflow created a lot more wind across the mic so the high rev stuff distorted a bit (oops) but as a side benefit, you can hear the turbo spooling down when the revs drop down to idle.

This on my recently deceased '05 WRX.

EDIT: The idea of this exhaust mod is NOT noise, it's about airflow. Tip size, length and shape largely determines noise, just like a trumpet/trombone. Change the length/size of the pipe the air has to go through, the sound will change.

[Cagie]

The mufflers on the TB STi are Hi-Tech units from what I've been advised.

Especially ones made domestically (Hi-Tech is a local company in Darlinghurst, Sydney and the mufflers are manufacturered in Bathhurst).
[EDIT -> Opps, Resonate already mentioned that]

You are correct. The factory in Bathurts is the old Everlast Muffler factory.

For those that are as old as me you may recall Everlast Mufflers prior being sold to Midas.

As for the owner of Hi Tech. Lets just say he knows his stuff and is a great guy.

[SkoobyGT]

Lambros always looks after me