Simons Mufflers

Simons’ silencers are straight-through units for a custom or modified exhaust, and each is named by its body and bore. The named bodies, ‘Super’, ‘Turbo’, ‘Heavy’, ‘Split’, ‘Slim’, ‘Handy’, ‘Duo’, ‘Duplex’, ‘Big’ and ‘Oval’, are made for pipe from 63.5 mm (2.5 inch) to 89 mm (3.5 inch). A separate series of compact silencers, Micro, Midi, Small, Medium and Big, is sized for 44.5 mm and 50.8 mm pipe. Larger round and oval cases, up to 300 mm across, take pipe up to 4 inches.

Each title gives the pipe diameter in millimetres and inches, followed by the material. Stainless steel is the more common, and many silencers are also offered in mild steel.

Choose the bore to match the pipe it joins, then decide how much case the car has room for. Where one large case will not fit, two smaller silencers in series are a common alternative.

Mount the silencer on flexible hangers so that engine movement does not crack the pipe, and leave clearance from the floor and fuel tank for heat.