Gutting an OEM Lib GT muffler for maximum airflow - 2009

[lozza]

cpitts, can you OR anyone else confirm

are the mufflers you gutted on your car, the same muffs as on a tbSTI, except the STI ones have quad pipes exiting them?

in other words, if I open up my 07 tbSTI muffs will I find the same innards as yours

cheers

[Arith]

in other words, if I open up my 07 tbSTI muffs will I find the same innards as yours

No offense, but I think it would be quite foolish to gut STi mufflers, considering how much they're worth on the market. You're better off selling the STI's to someone who wants the STi's as they are, and using that money to have a local muffler shop custom make you a new set which will suit your needs better.

As for your question, I believe the STi and GT internals are pretty close, but the STi have x2 outlets instead of x1.

[cpitts]

are the mufflers you gutted on your car, the same muffs as on a tbSTI, except the STI ones have quad pipes exiting them?

in other words, if I open up my 07 tbSTI muffs will I find the same innards as yours

No, my gutted mufflers were from a MY05 GT.
Would your STi cans be the same inside, most likely not. HOWEVER, they will have a very similar set of internals, ie: chambers, various pipes of different diameters to help remove engine throb noise.

An example of this is the standard WRX muffler compared to the STi muffler. Both have stacks of chambers in them, just different pipes going out of the muffler, see here:
05 WRX


05 STi muffler

[cpitts]

<snip>You're better off selling the STI's to someone who wants the STi's as they are, and using that money to have a local muffler shop custom make you a new set which will suit your needs better.<snip>

Arith is spot on here! If you have STi's, sell them and get a pair of customs with the remaining cash.

Muffler shops have straight through cans with twin outlets that you can use. Just keep the output pipe size the same and you'll keep the volume to a sensible level.

[lozza]

cheers guys.

[lozza]

sorry for opening up an old thread and possibly two cans of worms(opinions) BUT this seemed the most appropriate place to post....I've gutted my STI cans.

before you call me crazy like Ben and others who have gone there before me, I wasn't prepared to pay $1200 for hitech quads, wanted to keep the sti tips and factory look, in my case all up cost was $200 and they sound and feel GOOOOD.

I'm happy to have opened up these VERY restrictive muffs, their resulting sound/performance compliments my other intake and exhaust mods to date.

pics and sound to be posted.

cheers
Laurie

[drndrn]

ooo interesting.. will be waiting to see results.

[cpitts]

Good work Laurie!

I like to see people taking a bit of initiative and having a go at these kinds of things. Ultimately an engine is just an air pump so taking out ANY restrictions in the mufflers (all those pressure chambers) will translate directly to throttle response and maybe a little more peak power (less likely). What you WILL feel though is a change in the torque delivery (not peak torque) as this is all about airflow speed, not volume.
You should end up with a flatter, wider torque curve which translatest to better drivability around town (one of my target goals).

And yes, $200 is better than $1200. (another one of my criteria)

Would really like to see the snaps of the inside of the STi cans.
Also the sound must be great now, the STi pipes sound good as they are. With some decent airflow now, they should really come to life!!

[Arith]

Good job, Laurie! Even though we all had our doubts at the beginning, more people are doing this with all good results.

[cpitts]

Good job, Laurie! Even though we all had our doubts at the beginning, more people are doing this with all good results.

There's no arguing with physics. Fluid dynamics FTMFW!!!!

[tangcla]

Interested to know the noise difference as well. I may contemplate doing the same to mine pending the review/verdict.

[mikee]

eagerly awaiting! O_O

[smythie]

see his profile thread for his comments on the sound

[castek]

pointless on an NA, more trouble than its worth.

have a look on my youtube, castek88, i have a vid of the car with a hotdog instead of standard centre muffler and gutted rear