Active Exhaust for Headers

MKM34STAE – Active Exhaust for Headers, 911S Tailpipes.  $CALL
MKM29STAE – Active Exhaust for Headers, 911GT3 Tailpipes.  $CALL
Now you can have the sound and performance of a Sport muffler combined with the tranquility of our Street muffler!  Our Active Exhaust System for Headers is a true dual function muffler.  At idle and cruise the exhaust flows through the STREET MODE path giving a nice tone that is a little louder than stock so you can enjoy that flat six sound while carrying on a conversion in the cockpit.  Step on the gas and the vacuum operated valves open diverting flow to SPORT MODE.  This path relieves back pressure allowing full use of tuned headers for the power and sound you expect out of your Porsche at speed!
Dump pipes are adjustable and can be pointed out where they are seen or pointed down where they are hidden behind the valance.  These mufflers are designed for use on G-body impact bumper 911 but can be used on Early 911 or 914/6 with modifications to the dump pipes.  Optimum power is achieved when combining with our Tuned Headers.  Not recommended for use with carburetors or intakes that reduce the vacuum signal produced by the engine.  Minimum of 12″ vac required to fully close the valves.  Valve cracking pressure is adjustable and may be adjusted to compensate if vac levels are close to minimum.   Custom Valances are available for use with this muffler.  Active Exhaust Mufflers for Headers come in either 911S (tailpipes 11″ on center) or 911GT3 (dual center out) configuration.  Call for custom spacing options.  Muffler comes with all hardware to install and make fully operational.  These mufflers are build to order.  Please allow 1-6 weeks to ship, call if lead time is an issue.

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All M&K Exhaust mufflers are produced utilizing 321 stainless steel. 321 stainless steel is used in the aviation industry for it’s higher quality alloys which withstand high heat applications. 

M&K Exhaust is the only muffler manufacturer to offer 321 stainless exhaust systems for Porsche automobiles. Most other manufacturers use lower quality 304 stainless. 304 is not as durable as 321 in handling the constant heat cycling exposure produced during the lifetime of an automobile. 304 is also not as resilient as 321 in withstanding the acids given off by an internal combustion engine. If you are looking for the best a lifetime product can offer, 321 stainless steel must be your choice.

All M&K stainless performance mufflers are shipped in raw form. Optional finishes are available at an additional cost.

Note:

  1. Shipment to US 48 states is free
  2. Add $50 for shipment to international destinations, Alaska, Hawaii and Puerto Rico