90/92 db in australia

[chris]

hello i am after some help building an exhaust system to meet
aussie regs do you guys over seas run cats before mufflers if so some pictures would be great most that i have seen seem to be mufflers
only or are very busy with cat then pipe then 180 bend then muffler
then 180 bend and then out,as muffler lenght is about 450/500mm
hoping to put cats inside muffler probably not possible but unless
you ask you wont know
thanks chris

 

[Ian Anderson]

Chris

I believe Frank Catt has made his silencers with a catalyser inside the muffler. His unit is one box as opposed to 2 separate units

His units are also very quiet and have got many cars onto Goodwood where the noise Gestapo are really strict, but I do knot know claimed db numbers

See Wealden Engineering Development

Ian

 

[Dave]

Sadly you are going to have to do the Cats 180deg bend, muffler 180deg bend, resinators thing. It's the only way you will get the 92 DB especially at the 3500rpm rev range the test is carried out at........ Just comply and do your own thing after rego.

 

[Jim Cowden]

Chris

You can put cats inside mufflers.
I have done it.
Used 4" ss tube for the bodys.
Cat core you buy from a company called catco, his name is costa.

Dave is right you need more muffler, from your collectors you struggle to get more than 500 mm.
By the time you cone in have a cat ,have a muffler cone out and tails your muffler is not long.

Jim

 

[Darrell]

Hi Chris
I am not sure whether you are looking for historic correctness; i built up a log muffler across the back of my car. The cats are immediately after the extractors and the log is immediately behind these. My car was comfortably under 90 db.

 

[Dave]

Hey Daz
How about a pic of your set up?
I am about to make my Pit exhaust soon.

Cheers
Dave

 

[Darrell]

Dave
Will do,may take a few days.

Drb #46
LS1 G50