Compliant exhaust nsw

Zedn · #1 (**permalink**) 03-16-2016, 03:26 AM

Hi all,

Just wondering if those who have passed now noise test in the last few years can tell me what exhaust set up they used? I have factory ls3 cats, two hsv centre mufflers, but then not sure what else to put on it. Was think of just buying another 2 mufflers for the rear but don't know if that's quiet enough.

Also what pipe size? Was thinking 2.5"

boxhead · #2 (**permalink**) 03-16-2016, 04:43 PM

I used 6 foot of 3 foot chicken wire in each side pipe.
Folded over to fit in 3 foot long side pipe and rolled up like a toilet roll :-)

It still hasn't fallen out.

Slo-poke · #3 (**permalink**) 03-16-2016, 06:42 PM

Did that make a noticeable difference in noise? And was there any noticeable difference in performance due to the restriction ?

stephen low · #4 (**permalink**) 03-16-2016, 07:53 PM

Zedn

My original exhaust just squeaked in by 1 or 2 dBA and was the standard Ford AU cats on a 2 1/4" system I think with an X pipe and two proper 14" mufflers (ie not high flow) at the rear.

New 2 1/2" system is a lot bassier which in itself wouldn't help and is a mite louder overall. Using an X pipe, hot dogs and 14" mufflers these all high flow though.

Believe I recall the commentary that SS systems are slightly better noise sink and the X pipe and cats all help baffle to a degree.

Use a reputable exhaust provider for their knowledge and perhaps aim at a system leaving capability to build in additional baffling eg hot dogs perhaps if needed.

My first bloke nailed it sort of but not sure he had much knowledge.

Zedn · #5 (**permalink**) 03-16-2016, 11:48 PM

Thanks. I measured the hsv pipes and they are 2.75 down to 2.25 inch. Sounds like if I just run the factory set up to the intermediate muffler and then 2.25 into a second oem muffler it should be right. It's actually hard to buy oem mufflers as they are all high flow. The hsv rear muffler is way to big to fit under the cobra.

boxhead · #6 (**permalink**) 03-17-2016, 12:17 AM

It did bring the noise level down a fair bit, also took the ear splitting "Bark" out of it.
I did not notice a decrease in power, but i dare say there would have been something changed.

Quote:

Originally Posted by Slo-poke

Did that make a noticeable difference in noise? And was there any noticeable difference in performance due to the restriction ?

stephen low · #7 (**permalink**) 03-17-2016, 03:15 AM

So just a slight thread hijack related to exhaust note, tone and warble??.

Would the state of tune of an engine or any other factor affect what you hear from the exhaust output.

I ask as my new system sounds terrific at idle but I'd describe the noise under power as perhaps uneven with a flutter. Not that my engine seems to be much out of kilter either! Am thinking my compromise to 2.5" for the moment may be having an impact.

Gav · #8 (**permalink**) 03-17-2016, 02:41 PM

Most definitely.
Displacement, compression, firing order, cam, heads the list goes on to what will change the exhaust tone.

SydneyChris · #9 (**permalink**) 03-29-2016, 03:08 PM

Did something rather ugly, but effective for mine.. rear exit pipes with two valiant mufflers paired together on each side. Liverpool Exhaust did the work.. effective for rego purposes..

Have seen them also do a very clever active noise cancelling solution with two converging pipes per side on a Pace car.. relatively small muffler required to get a rego compliant result.