AutoSpeed - Giant Muffler Comparison

What to Buy

The following table contains the best of each type of those mufflers tested. As can be seen, a straight-thru design gives easily the best mix of noise suppression and flow.

Muffler Type	Best example	Flow	Suzuki static noise	Cobra static noise	Seca static noise	Seca full-load noise
Baseline	-	353 cfm	102 dB(A)	99 dB(A)	100 dB(A)	122 dB(A)
Straight Through	Genie Tornado	359 cfm	91 dB(A)	90 dB(A)	89 dB(A)	107 dB(A)
Tri Flow	Genie Turbo	252 cfm	87 dB(A)	88 dB(A)	89 dB(A)	107 dB(A)
Dogleg	Walker Lukey L0099	285 cfm	93 dB(A)	91 dB(A)	90 dB(A)	108 dB(A)
Baffled	Berklee BB3912	162 cfm	85 dB(A)	88 dB(A)	82 dB(A)	105 dB(A)
Factory	Mazda 929	207 cfm	84 dB(A)	88 dB(A)	80 dB(A)	106 dB(A)

Unless you need to fit a muffler just so that you can pass a noise test, steer clear of baffled mufflers - their flow is typically only about half that of a same length piece of empty pipe. Tri-flow (reverse flow or turbo mufflers) also typically flow badly - even a good one only has about 70 per cent of the flow of an empty pipe. However, tri-flow designs can be significantly quieter (but not always!) than straight-through designs. Tri-flows can also have a deeper, mellower sound. A good dogleg muffler gives a very pleasing note, together with adequate flow and noise reduction.

The best bet then is a straight-through muffler. If used in conjunction with a cat converter and good resonator (or simply a second straight-through muffler), you will have a system that definitely has excellent flow and very probably has a good quality, quiet sound. The latter unfortunately can't be guaranteed - too many other factors determine the actual noise output.

Our recommendations are: