CARBON FIBRE 'AFTER' MUFFLER, 'SUPER' MUFFLER SPECIFICATIONS

The below sizes are based on the outlet diameter (id) of the muffler, match

this to the outlet diameter of the engines exhaust system (pipe or muffler).
Size Type Weight gm Max. dia mm

X

 Length mm 2 cycle 4 cycle
7.0 mm After 19 31

x

 139 .25 .50
7.0 mm Super 23 31

x

 139 .25 .50
8.5 mm After 21 33

x

 147 .40 .80
8.5 mm Super 28 33

x

 185 .40 .80
10 mm After 26 35

x

 185 .45 .80
10 mm Super 34 35

x

 198 .45 .120
12 mm After 29 37

x

 165 .60 .120 - .160
12 mm Super 39 37

x

 209 .60 .120 - .160
14 mm After 44 42

x

 205 .90 - .108 .160+
14 mm Super 53 42

x

 245 .90 - .108 .160+
16 mm After 68 49

x

 235 20 - 35cc  
16 mm Super 80 49

x

 290 20 - 35cc  
22 mm After 140 56

x

 285 35 - 65cc  
22 mm Super 160 56

x

 370 35 - 65cc  
4 Stroke Rectangular 33 38 x 33

x

 177 .60 - .90 .120 - .160

PLEASE NOTE... When using in a high heat / low cooling environment i.e., cowled, high nitro, helicopter etc. It is best to use one size larger.

AFTER MUFFLERS

The Bolly After Mufflers have been designed to suppress exhaust noise levels of conventional mufflers and tuned pipes (P-Types), whilst remaining a practical size and low weight.

Amazingly, in many cases the noise levels are reduced markedly AND power levels increased, when using a Bolly After Muffler. As a result of their use, is the extra heat that can be generated, especially if the muffler is too small or the prop load too big. See the Book section on 'thermal efficiency'.

The average noise drop of 5dB for a 200 rpm increase. In some instances, we have measured a noise decrease of over 20dB (in a marine set-up).

Do not attach an After Muffler directly to a 4 cycle engines exhaust pipe (the heat will melt the silicon). For 4 cycle engines, use a flexible steel exhaust (as available for most 4 cycle) to position the After Muffler (and silicon joiner/s) further away from the exhaust outlet.

Optimum performance is obtained by using an After Muffler of similar or larger size than the exhaust outlet ie, an 8.5mm or 10mm After Muffler on a 8mm muffler outlet of a .40 engine muffler.

The Super Muffler

The Bolly ‘Super’ Muffler has an extra muffler chamber in comparison to the After Muffler, hence the longer length. The Super Muffler is more effective at noise reduction than the 'After' muffler. The Super Muffler can be used as ‘the’ muffler, when used in conjunction with an alloy exhaust header.