SuperTrapp mufflers are the only USDA Forest Service Approved spark arrestors that do not rely on restrictive swirl baffles or fragile screens. Sparks are funnelled into a collection chamber in the end cap, while exhaust gases exit between special diffuser discs. Even if the collection chamber filled to capacity, the small 0.023" gap between the discs still provides a back-up layer of spark protection.
The 5" diameter SuperTrapp 5S Series muffler is recommended for engines up to 100 HP, but it can also be used on engines up to 200 HP where compact size is a greater concern than noise reduction. An optional 5S Series Resonator (Part No. ST-5S-5500, sold separately) can be added to further reduce noise without affecting power. The 5S can also be installed after a conventional muffler in installations where maximum muffling is required. In fact, it can be tuned so quietly that mechanical engine noise may drown out the exhaust note!
This kit includes a male threaded inlet flange (to fit an exhaust pipe with 1" female NPT threads), clamp, end cap with collection chamber, and center retaining bolt.
Requires diffuser discs, sold separately:
3-Pack of 5 inch Diffuser Discs (Part No. ST-5S-6503)
Typical installations should use 1 disc per 7 horsepower for proper back pressure (e.g., an 85 HP engine should use 12 discs). Using fewer discs will further reduce noise but will also cause some power loss. More discs should be used on engines rated below 2400 rpm, or if the 5S will be used in conjunction with an existing muffler.
Optional resonator sold separately:
SuperTrapp 5S Resonator (Part No. ST-5S-5500)
Adding this resonator will reduce sound levels by 4 to 6 dbA without restricting power. For the most effective muffling, start by adding the resonator before subtracting diffuser discs.