The Power Of The Pulse Wave

Bisimoto Reinvents The Exhaust With Porsche’S 911 Classic

- Aaron Bonk

Within those tubes of steel running underneath and hidden from sight is where spent exhaust gases exceeding 1,200 degrees F move at the speed of sound, interacting with what lies at the other end. It’s here where an exhaust system’s ability to purge an engine of all those fumes will determine just how much power can be made and how much noise there’ll be while doing it. And according to the people at Bisimoto Engineering, as far as Porsche’s ’75-’89 911 is concerned, there’s a whole lot of room for improvement—and in a most unconventional way.

THE BISIMOTO SOLUTION

The 911’s rearmost exhaust bits are heavy. They’re also restrictive, and a few decades later, they don’t look all that great either. Forget about the dangling tube hanging off the side of Bisimoto’s Pulse Chamber Without any supporting mods, the modest little bolt-on’s good for an easy 15 whp. How it manages that 15 hp is the part you’ll care about, and it starts with this exhaust’s ability to harness the power of pulse wave.

IT’S ALL ABOUT SCAVENGING

The namesake of Bisimoto’s deceivingly simple-looking exhaust is indicative of its ability to take advantage of an engine’s exhaust pulse waves. According to Bisimoto’s founder and lead engineer, Bisi Ezerioha, here, kinetic energy generated by resonant exhaust gas pulses can be harnessed to increase scavenging.