991 SW Center Muffler Bypass Pipes

Description

Works great with FISTER 991 SPORT MUFFLERS!

3-D CAD designed with optimal flow, fit, weight savings and sound enhancement, our system replaces the center muffler on any Porsche 3.4L and 3.8L 991 Carrera. By utilizing appropriately-sized diameter tubing and straightening out the flow, we achieved our desired sound and minimized resonance. Our direct bolt-on exhaust installs into the factory location without any modification or compromise and is completely reversible. An overall weight saving of 7 pounds is achieved with a more aggressive idle and outside bark with a deeper tone. On the inside you can still talk on the phone and/or listen to the radio without any compromise. When you apply aggressive throttle you can hear a more exciting pitch and tone. Playing around with the throttle induces crackles and deeper howls more fitting for a 911.

The stock center muffler does not utilize a straight-through design and instead collects and merges in the center (hence you can often see a hot spot in the center) causing the sound to be more muted than some would like. Expect slightly better performance due to optimized exhaust gas flow.

Some cars, especially with higher mileage, may experience a slight increase in vibration (especially on PDK-equipped cars) when idling at a stop in Drive mode. These vibrations usually occur due to build-up from the oil breather in the throttle body, which can be alleviated by cleaning the throttle plate and bore. Additionally we have seen instances where the OEM (Bosch) Throttle Body has a defective bore/plate and with a little wobble or play in the throttle body, needs to be replaced after as a little as 15k miles. Inspect this carefully if you notice any vibration on these models. Most 991 cars with 30,000+ miles should have this cleaned, as even a tiny amount of build-up can effect the idle speed. We also recommend changing the spark plugs at the same time, which can make a significant difference in how smooth the car runs at idle. We have also noticed that the engine will run smoothest in Sport  or Sport Plus mode due to the increased idle speed.