DEVELOPMENT: Our aim was to increase the volume of the rear exhaust while maintaining a refined tone and level of volume, even with upgraded catalytic converter sections. The factory valves are electronically controlled unlike older “open or closed” vacuum-style valves. Able to work variably, the valves will gradually open and close depending on several factors of engine operation. Even under full throttle application in Sport mode, the valves will still not stay open 100% of the time. With this in mind, it was imperative that our system have a smooth transition during valve operation.
To tame drone, we made use of our bespoke X-pipe muffler. Internally, this muffler is quite unique. It has little to no restriction in the flow path, using straight-through piping that is perforated to allow exhaust gases to escape and become muffled in the surrounding packing material of the muffler body. We incorporated an internal X-pipe to allow the exhaust flow to merge smoothly. These characteristics combined were crucial towards reducing and smoothing out the drone in the 2,000-2,400rpm range while enhancing that higher pitched note we were after in both the valves closed and open conditions. With valves open exhaust gases are free to flow through 3″ piping with an x-pipe to enhance the tone before exiting out the tips. Exhaust gases still have a secondary flow path to “talk” with the muffler, encouraging a fuller, more robust tone.
