Crock Posted July 15, 2016 Share Posted July 15, 2016 I am currently in the process of putting a 308 V8 in my HQ The 308 has a lumpy cam and Hurricane tuned headers I will need to have a low volume certification done once i am finished At the moment i am thinking about the exaust pipes I want to have a good loud sound I have been told to do straight pipes which i guess means no muffler The problem is when it goes for cert i dont think that will pass the sound test of under 90 decibells I would like any advice on this Thanks Quote Link to comment Share on other sites More sharing options...
AllTorque Posted July 15, 2016 Share Posted July 15, 2016 Have a read of this thread //oldschool.co.nz/index.php?/topic/39978-muffler-tech/ You will need some sort of muffler. Flowmaster mufflers are good on a V8 if you want a good rumble. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 15, 2016 Share Posted July 15, 2016 Fit buy pass valves. Quiet for Cert and WOF and loud for the track or when you just want more noise and it's legal. 1 Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted July 15, 2016 Share Posted July 15, 2016 My neighbour over the road has them on his 350. He alwaysopens them when he backs up the drive to piss off the other neighbour who he dislikes. 3 Quote Link to comment Share on other sites More sharing options...
Muncie Posted July 16, 2016 Share Posted July 16, 2016 A 2 chamber Flowmaster will be plenty loud and sound fantastic you wont be dissapointed a 3 chamber will still sound fierce but be a bit quieter however 3 chamber flowies are a huge muffler you might struggle for space. Go twin 2.5 inch into the muffler then single three inch over the diff. Quote Link to comment Share on other sites More sharing options...
cletus Posted July 18, 2016 Share Posted July 18, 2016 no, they are not. Â http://lvvta.org.nz/documents/standards/LVVTA_STD_Exhaust_Noise_Emissions.pdf 2.1 (3) 1 Quote Link to comment Share on other sites More sharing options...
Muncie Posted July 19, 2016 Share Posted July 19, 2016 Could that be interpreted as they may be fitted but have to be capped and fitted with fittings that require a tool to remove? Eg nuts and spring washers to pass Cert and warrant of fitness. Quote Link to comment Share on other sites More sharing options...
Crock Posted July 19, 2016 Author Share Posted July 19, 2016 A 2 chamber Flowmaster will be plenty loud and sound fantastic you wont be dissapointed a 3 chamber will still sound fierce but be a bit quieter however 3 chamber flowies are a huge muffler you might struggle for space. Go twin 2.5 inch into the muffler then single three inch over the diff. Quote Link to comment Share on other sites More sharing options...
Crock Posted July 19, 2016 Author Share Posted July 19, 2016 Why 2.5 in and 3 out Will 3 in and 3 out be different Quote Link to comment Share on other sites More sharing options...
Muncie Posted July 20, 2016 Share Posted July 20, 2016 Mainly its because ive had this exact setup on my commodore and it gives good results and ground clearance. 3 inch is bigger of course so everything is bigger and harder to thread around things. Ive driven an Hq with twin three inch right thru and it caught in everything which quickly wrecked the headers. Quote Link to comment Share on other sites More sharing options...
Kiwibirdman Posted July 20, 2016 Share Posted July 20, 2016 With a 308 twin 2.5 is more than enough. in fact for driving round on the street twin 2 inch is plenty. The HQ with a 308 in it I had years ago sounded awesome with twin 2 inch pipes and cheapy straight through mufflers. I put dump pipes on with caps that could be unbolted without jacking the car up and it ran mid 14's all day. Quote Link to comment Share on other sites More sharing options...
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