Muffler quietening

[byroncobra]

My hayabusa powered Rush is coming along slowly with an engine start and test drive recently.

It's apparent that the muffler is a little noisey, although it passes in the UK, it sounds sensational....

I've wrapped the exposed headers in this cool looking rock wool tape and sourced a heat shroud from Fleetguard....straight off a Kenworth, to cover the muffler. Hopefully the engineer will be satisfied.

Anyway, the research that I've found suggests jamming steel wool up the muffler and wiring it in. Any thoughts on how hard to pack it in and what coarseness to try, stainless too?

There is nowhere to put an internal baffle/reducer as i did with the Cobra.

[letsboogie351]

Greg
This bloke tried but I don't think it made much difference. Maybe try a reputable exhaust shop.

Dax Rush Hayabusa Exhaust Noisy - YouTube

this does sound pretty good though

Doug

[spookypt]

Greg if your up at MP I'll fill u in on what I did with the stainless. The $2 shop is your friend.

Spookypt

[leroy17]

I remember reading where someone stuffed chicken wire in the pipe. When I say stuffed I mean a length that was folded over and over and over.

I can't picture what access you have to do this.

[Rog246]

If you get a spud and shove it up the exhaust.......................oh wait a bit......that's for just married cars...............Sorry !!

[guye]

I was watching an episode of one of those American chop shop series the other night (can't remember what it was called, like those West Coast guys that restore muscle cars or make perverted classics).

Anyway, they were making their own mufflers with ~2 1/2 inch pipes drilled with hundreds of ~10mm holes encased on coarse grade steel wool - maybe two layers - then two layers of chop stand fibreglass mat, then all packed in a 4inch pipe.

Not sure if that helps, but someone else might have seen them and can tell you show it was perhaps...

[dhs.buckley]

i once used steel wool on an old holden that needed a roadworthy, unbolted the glass pack muffler and shoved 2 pot stainless mesh into one end worked a treat.
it was 121 db came down to 96db and passed the roady with about $3.00 spent.

[byroncobra]

Thanks for your input, good and bad.......
Doug, good spotting, that video shows the same muffler as mine but it's already packed with the glass padding.
I was thinking that I need to stuff the steel wool into the inner perforated tube, much as Mr Buckley suggests.
The problem is going to be weaving wire or something thru the sides og the muffler and all that packing to stop it blowing out.
Matt, unfortunately I can't get to MP this weekend.......my 18 year old insists that I stay home for her birthday party! Can you let me know what you did?

Cheers

[damage]

what about this sort of idea.

Dynatech Vortex Insert Cones, Exhaust Insert, Vortex, Cone-Style, 7.25 in. Long, 4 in. Diameter, Stainless Steel, Each

[kyleb]

Hi Greg
Supertrapp is worth a look. They have quite a range of products to do what your looking for.
I used 2 of them for my Cobra to pass noise testing for rego.
You can also adjust them for tuning.
Cheers

[renovationinnov]

Byron cob [greg] I have noise diverters in my side pipes
I got them from a muffler shop
they are adjustable to very restricted [quite] or fully open no restriction all noise
so i'll let you know what noise they allow as my noise test is on Thursday
but on the dyno I ran them in full open & half restricted & made some decent kw/n power from an ls1
rob

[spookypt]

Kids hey Greg! I need to see your set up to explain proper but I've dabbled with
All sorts of stuff. Super traps, cones, cut down cats, spirals, perforated tube, butterfly's, stainless scrubb wrapped pert tube, fibre matt wrapped tube, bananas the works....

If it's a muffler type set up I know Pete ransom ran super traps on his 40 with good success but u can't just affix them and hope they work. Had a fresh Porsche run em at qr and bang. You need to tune them.

For a cobra with live pipes perf tubes wrapped in matt worked the best for noise reduction while keeping flow almost unaffected. They made a huge difference on both live piped cobras... But as Scotty would say, if u want it quieter put a turbo on it!

Take some pics of your set up and I'll give u my 2 c worth.
Trust the 18th goes well. Shot gun on standby always helps you feel more at ease.

Spookypt

[Russell9318]

Originally Posted by Rog246

If you get a spud and shove it up the exhaust.......................oh wait a bit......that's for just married cars...............Sorry !!

I hope those married cars have stayed with in their own social status, I mean like a Lada Niva and a Ferrari, what would the offspring be.
Come on all you doctors out there, what would the offspring be??

Cheers

Russell

[400TT]

You can insert some homemade custom spirals into the centre of the muffler. Something to make the exhaust gas work and get more optimally silenced by the muffler. You can make tripod supports at end of the spirals and attach to inside of muffler tube.

If you want to go the steel wool route, you need to make baffle plates with holes in it to support and trap the steel wool. You can make them with a tab that is supported by bolt or screw. You drill a hole in the exhaust pipe, inserted you baffle plate and secure it with a screw through the tab. You will want the coarse steel wool from hardware shop and plenty of it, packed pretty hard. It is amazing what exhaust gas will travel through.

A little trial and error will get you there.

[byroncobra]

Here's a few pics.....

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[IMG]http://[url=http://www.clubcobra.com/photopost/showphoto.php/photo/83949][img]


[IMG]http://[url=http://www.clubcobra.com/photopost/showphoto.php/photo/83951][img]


I think stuffing steel wool is the easiest answer (if it works). I can jam it up the centre tube and wire it in, the end pipe should hide it all.

The cones look a bit like what I did for the Cobra, Damage, but I don't think I'll get one to fit in there

I might give you a call Craig to find out about "spirals"

Cheers Matt, keen to hear you're 2 bobs worth too........party went well, hope you had a hoot at Morgan Park. The weather was superb I'm guessing

[byroncobra]

arhhhh, bluddy pics are in my gallery........

[damage]

The spirals are pretty simple, google them they're about $60-$70

[guye]

Helpin' out a Cobra-bro...

Here's those pics for you Greg.