Bisimoto-Spec, Porsche 911 Pulse Chamber, 1978-1989

Using advanced wave cancellation to reduce unwanted sound frequencies while enhancing scavenging through precision pulse tuning, the Bisimoto Spec Pulse Chamber for the Porsche 911 SC, 911, and M491/M490 (1978 to 1989 3.0–3.2L engines) delivers measurable performance and refined sound.

The result is a deep, throaty exhaust note with a documented 11–17 horsepower gain — with no other modifications required. Unlike conventional mufflers, this design improves both sound control and power while saving over 15 pounds compared to the factory unit. Constructed from pure stainless steel and weighing just 5 pounds, each unit is proudly made in the USA.

An optional removable arrestor provides 18+ decibels of sound reduction with no horsepower penalty. Secured with two 6mm bolts, it installs or removes in minutes for a more aggressive tone when desired.

Available in stainless steel, high-luster silver ceramic for a classic coated finish, or subtle black ceramic for a refined, understated look. Manufacturing prototypes are also available (used in testing and may show minor cosmetic imperfections). Please inquire for current availability and finish options.

Modern day science, for your classic Porsche.