Active Exhaust With Pre-Muffler

 

THE single most powerful bolt-on exhaust component for your SC or Carrera.  The active exhaust valve is activated by engine load, opening during aggressive dips into the throttle.  YOU decide the sound characteristics of your 911 by your driving style and choice of main muffler.  Removable tailpipe silencer cuts the sound level of the open valve in half should you desire a less aggressive note when you get on it.  This system is STOCK QUIET during idle and cruise with a SPORT SOUND under acceleration when coupled with an OE muffler and slightly louder than stock using our MKM33 muffler.  Designed using a dyno, this system partially waste gates exhaust flow at the optimum ratio for peak performance.  The tailpipe silencer was also designed using the dyno to silence the flow just to the point where performance gains began to drop off.  Dyno graph shows difference with valve open and closed.  Total system showed a 19HP IMPROVEMENT on the 3.2L Carrera.  Improvements are further enhanced with a matching chip to take advantage of the reduced back pressure (chip not included).

Pre-Muffler Active Exhaust is designed for use with all impact bumper Porsche 911 1975-1989 models having OEM heat exchangers.   Weight is 8 pounds.  This muffler is designed for ultimate performance and sound using an F1 style merge collector, straight through 2.5″ flame tube, heavy duty vacuum activated valve and oversized exit flange.  O2 sensor is located at the F1 merge for optimal reading of all cylinders.  When installed on the Carrera this product alone will surpass the performance increase seen when converting from the OEM exhaust system to standard 1.5″ SSI heat exchangers.  Sound level when valve is closed is the same as OEM pre-mufflers which is a bit louder than a catalytic converter.  Active Exhaust comes with everything needed to install.  See INSTALLATION INSTRUCTIONS tab for helpful hints.  Complementary products are our MKM33 Single Outlet muffler or MKM73 GT3-Look muffler.