S1 Honda/Duratec Quiet System
Okaaaaaay - after much persuasion - here is my solution to the NOISE problem on these conversions. More power = more NOISE! Whilst the standard 2bular 7"dia K-Series silencer has been fine for most trackdays, these conversions have been having problems meeting decibel limits.
I have used the 2bular H2 silencer. This has two internal noise-cancelling chambers. A complete PITA to fabricate and weld. You can see the internal spot-welds used to secure the plates forming the chambers. With no straight-thru perforated core-pipe, a lot of strength is lost in the unit, so doubling up on the end-plates helps reinforce those areas. I use a double-skinned silencer to cancel any drone caused by the open chambers.
So, a double-skinned silencer and 6 baffle/end-plates - more weight and cost but all necessary to help control the decibels.