Gutting an OEM Lib GT muffler for maximum airflow - 2009

[Sentinel]

But it's back breaking...

You had me till you said that.... I've already got one of those!!!!!

Exactly why I added it with your recent spinal discussions and seat activities. Might be well worth getting it priced up. SO worth while to bring the stereo up to quite a good standard for a factory item.

Haha - good man! Wouldn't happen to know someone... Someone that knows exactly what to do, lives in Melbourne, someone that I could trust not to damage my car, someone that's done it done it before..........

[cpitts]

Now hooooooooow did I NOT see that coming.

I'll stick it on the list of the detailing day tutoring, muffler gutting sessions and now car deadening days. Busy boy.

[Sentinel]

Now hooooooooow did I NOT see that coming.

I'll stick it on the list of the detailing day tutoring, muffler gutting sessions and now car deadening days. Busy boy.

Well, you know... Helping a fellow (broken) member out...

Haha!!

[at last!]

Honestly folks, doing the doors with sound deadening is not that hard or backbreaking. You can have a door trim off in 5 min's and then it's up to you how pedantic you get on applying the deadener. See other thread on how to do this.

Just buy a box of surgical gloves at the local chemist/supermarket and a cold beer and get into it. Change the gloves often. Use a blunt object to press the deadener onto the door. I used a firm brissle dish brush. I also recomend putting down a drop sheet and using a small box to sit on.

Honestly it's very easy...just put on the radio and get a beer and do it.

Happy to give more detailed info/help to anyone who wants it.

Andrew

[04GTLIB]

cpitts.
I started doing my standard mufflers today at work.
I've looked into getting 1 3/4" perforated pipe to run between the inlet and outlet and I'll then pack it with exhaust wadding/packing.
I will try and takes some pics of the perforated pipe installed and of the packing/wadding before I seal it up.
Thanks for starting things off with this post.

Cheers,
Rusty.

[cpitts]

No stress.

In all honesty, I'd give the perforated pipe a miss. I had my cans welded up by professional engineering and flow designers and I discussed all the flowing options and they advised:
- given the bends from the inlet to outlet any perforations would end up creating back pressure
- the 'ideal' solutoin was a solid pipe (larger than the inlet and outlet pipe) with very few ~3mm holes drilled along it to let some pulse pressure waves out into the outer muffler can

They went ahead and did this and it wasn't a cheap exercise (when I finally got the bill) and if I had my time again, I'd just leave the muffler can empty, purely for simplicity and the elimination of a weld trace around the back muffler pipe where the connector pipe was fixed to the back of the can.

My current recommendations on this exercise is: Cut, Gut and Shut. Quickest, lowest cost and I'd dare to say as good airflow as any other solution with the standard muffler.

If you've got the time and tools, do whatever you feel though. Free country.

Out of interest, this is the mob I used: http://www.agfab.com.au/
As you can see, they do pipework for refineries, hardcore underground pipework, etc. These little cans are entertainment value for these guys, that's about it.

[04GTLIB]

Bringing up an old thread guys, but wanted to say I finally got around to finishing these and installed them today.
I'm absolutely stoked with how they sound, they seem to be no louder than the STI mufflers.
My apologies guys, I couldn't get any before and after pics, as these would have made it a little easier to explain, but, I'll try my best.

- Firstly, I prepared (gutted) the standard mufflers exactly the same as Craig (cpitts) did.
- I then purchased some 2" stainless mandrel bends, and 2 lengths of 2" stainless perforated pipe.
- The mandrel bends were cut in half and then each half was trimmed up so when installed and welded in, both openings faced each other perfectly.
- I then welded the perforated pipe between the two ends. The perforated pipe was then wrapped in 2 layers of kayo wool (insulation) held in with stainless tie wire, I then filled the rest of the muffler up with off cuts of kayo wool (5cm x 5cm pieces).
- They were then closed up and welded shut.

I will try to post up a pic tomorrow taken from the tip end, so you can see the perforated pipe and mandrel bend. I will also try and post up a sound clip.
All in all, this has been a really interesting thing to do and I'm happy as with the sound of them so far.

A big thanks to Craig (cpitts) for providing the inspiration.

Cheers,
Rusty.

[Hotwire]

Rusty,

Did you do the welding yourself or pay someone to do it? how much did the bends & pipe cost as I would like to know the overall cost of this, as I would like to increase the note on my 04 Wagon also, without paying to much

Cheers
Lee

[04GTLIB]

Rusty,

Did you do the welding yourself or pay someone to do it? how much did the bends & pipe cost as I would like to know the overall cost of this, as I would like to increase the note on my 04 Wagon also, without paying to much

Cheers
Lee

Lee.

I did this all through my work mate, one of the perks of working at BP.

In all honesty, if you were to buy all the required pieces and then pay someone to do all the work, it would be cheaper buying a second hand set of Hi-tech's or STI's from one of the forum members.

Sorry mate, this probably isn't the answer your looking for, but I'm only being honest.

Cheers,
Rusty.

[04GTLIB]

This is the best pic I could get guys.
I really should have taken some pics during the mods.



Cheers,
Rusty.

[Arith]

Good work Rusty! I look to any sound clips you can provide in the future as I'm curious on their sound.

[cpitts]

<snip>
A big thanks to Craig (cpitts) for providing the inspiration.

Cheers,
Rusty.

w00t!!

The solution you've put in place is about as good as it gets without just putting a straight through pipe in.

Will be interested to hear what you think of it when you floor it through to redline in S# mode. Find a tunnel if you have one close and wind down the windows and do some WOT bursts.

[parso_rex]

I just might have to give this a try , anyone got a spare set of mufflers they want to off load......cheap

[cpitts]

Rusty,

Did you do the welding yourself or pay someone to do it? how much did the bends & pipe cost as I would like to know the overall cost of this, as I would like to increase the note on my 04 Wagon also, without paying to much

Cheers
Lee

The pipe bending is the expensive part of the exercise! You'll get a very similar result (but probably a little quieter) by simply gutting it out and getting it rewelded closed. Total cost should be ~$200ish depending on who you get to do the welding and how much tidyup work they need to do from your 'gutting' skills.

[smythie]

I just might have to give this a try , anyone got a spare set of mufflers they want to off load......cheap

Might be willing to provide a set for exchange