Glass pack sidepipes

[Cobrakiller]

Running live side pipes and keeping the noise level within the regulations is a challenge. I am thinking of using two 2.5'' 24'' glass pack mufflers ( hot dogs etc) Engine is a stock 430 hp LS3 with factory VE catalytic converters. Anyone tried this type of set up before? I need to keep the outside diameter of the mufflers under 4'' due to space limitations. Appreciate any feedback or ideas.

[guye]

The VE cats make a big difference, so that's a start. On my undercar system I had VF cat, one muffler (straight through) two baffle plates and three steel wool balls on each side and the system is 2.5" stainless pipes. That kept it under 90db each side as required.

Sorry, I know that's not exactly helpful for your sidepipes, but the baffle plates and wool balls might help. Are you after temporary of permanent notice reduction?

[Gav]

Glass pack mufflers are not known for being quiet.
If you are serious about muffling down your side pipes you might want to look into building them with a spiral or baffle arrangement.
I ran 2.5" perforated pipe packed with stainless wool and then wrapped with weld blanket.
They weren't the quietest but they were easy to live with.
The weld blanket made the surface temp of the pipes lower too.

[kyleb]

Originally Posted by guye

The VE cats make a big difference, so that's a start. On my undercar system I had VF cat, one muffler (straight through) two baffle plates and three steel wool balls on each side and the system is 2.5" stainless pipes. That kept it under 90db each side as required.

Sorry, I know that's not exactly helpful for your sidepipes, but the baffle plates and wool balls might help. Are you after temporary of permanent notice reduction?

And be careful not to overheat your 'wool balls'
That would be bad !!

[kyleb]

I found the easiest way to lower the db from my sidepipes is put in earplugs!!
Join the revolution I say..

[Cobrakiller]

Anyone using the spiral inserts? I have heard good things about them. The noise level is to pass the noise police test.

[MikeFromPerth]

What type of cobra is it? Just interested as I'm in Perth too.

[Paintwerks]

Originally Posted by Cobrakiller

Anyone using the spiral inserts? I have heard good things about them. The noise level is to pass the noise police test.

I believe Bernie (BMK) runs them in his sidepipes on his Kirkham. From what I understand, he left them in even after getting the car on the road.

[kyleb]

A possible solution:
You already have the cats fitted which drops the noise level some.
Fit the spiral wound internals with supertrapp ends.
Would be compact and adjustable.
How is the noise test done in W.A and what level do you need to achieve?

I used the magnaflow glass packs on my sidepipes which were ok when cruising but when you stepped into it then it would bark !!
We have to meet the noise level at a specific RPM which is where the ability to tune comes in.
Then you come across the performance/noise issue as well.
Cam changes etc will change the noise characteristics also.

[LoBelly]

Originally Posted by Cobrakiller

Anyone using the spiral inserts? I have heard good things about them. The noise level is to pass the noise police test.

I am running auger style inserts inside my sidepipes
The casings were custom made and the auger sits inside a perforated steel tube which is the inner for the main body of the side pipe.
Overall a 4" OD IIRC

They took a lot of bark out of the exhaust
I have followed my car from behind and cant really hear the exhaust
I have left them in for the last couple of track outings

LB

[Bryan Wilson]

I have glasspack sidepipes. And they arn't excessivly loud. I include a thumb sketch of their construction. I couldn't get pic to load so look at page 5 in my gallery.
Cheers,
Bryan

[Modena]

Mine are a 4" tube, 2.5" perforated inner which then has pot scourer donuts stretched over it. Sorry dont have a pic of the scourer setup to hand. Dont use steel "wool" as it can burn, whereas the scourers are more like wire mesh. I got the scourers from Woolworths, 3 to a pack were about $0.60 I think, needed less than I thought I would. Anyway with all this my system is pretty quiet but I think the cats do more than the pipes....

Modena's progress update

[guye]

Yes. To be clear, we used steel scourers not wool (as Ben says). And in the undercar setup I inserted them towards the rear, further away from the hot engine end as possible (as Kyle says). I get that this isn't so easy in sidepipes!

[Cobrakiller]

I am thinking of using these side pipe covers, they have a fiberglass insulator on the inside to keep the heat down. ( I have a confession, I don't own a cobra instead I have 63 Corvette coupe but my build is an ICV and this is the only forum that deals with ICV's, a lot of our issues are similar though) Max. pipe o.d. is about 3'' to 4'' depending on how far you space the covers out.

[Gav]

What ever you do, don't try to be different and put a Windsor in it!

[deano59]

Originally Posted by Gav

What ever you do, don't try to be different and put a Windsor in it!

why would he want to go slower for lol i like those covers not seen those before

[Rossba]

I had 2 cats and 4 mufflers on a under car system with a stock engine and was still 1db over in Victoria.
It was quite than a BF GT
Good luck getting it quiet

[Jaydee]

I have a fg cat on either side with a 1.2 metre hotdog with perforation, and I just had my first inspection. They produced about 100 db, then I stuffed 5 scourer into the end and it brought it down to 95 db. So Now I am looking for a very small diameter muffler to quieten it down to a legal level.
302 windsor. The engineer went through a lot of jargon about frequencies etc and tuning the exhaust to counteract them. We played with the idea of inserting to tin can into the end with a stiff wire and sliding the can inside the hotdogs whilst it is running until you hit the sweet spot . The test is done running the engine in neutral at 3300 rpm.
JD

[MikeFromPerth]

Originally Posted by guye

Yes. To be clear, we used steel scourers not wool (as Ben says). And in the undercar setup I inserted them towards the rear, further away from the hot engine end as possible (as Kyle says). I get that this isn't so easy in sidepipes!

Just so I understand... Are we talking about these sorts of things?

https://www.woolworths.com.au/Shop/B...roductId=10924

Or perhaps these?

https://www.woolworths.com.au/Shop/B...productId=2774

I never would have thought of stuffing such a thing in there! It really works huh?

[Modena]

yes these are what I used