AP Axle Back Exhausts

Exhaust Muffler

Creating a OEM replacement exhaust may seem easy, but there are key elements to take into consideration as well. There is a fine balance between performance and sound. With the engineering Porsche has done in the new 991 including the economy mode, drone will be even more present than before. If you are not in Sport Mode, the car can be running at 1500rpm as your cruising at 40mph down the road. Previous 997 Turbo had a drone spot of around 2200-2800rpm. So reducing backpressure to gain performance while keeping a clean sound for daily driving is priority one! Typically a X-Pipe design gives the car a bit of a muffled tone. That is because of the turbulence where the X junction is merged. Many people like this sound, however the turbulence can affect performance. We chose to do our system in full 3 inch Titanium with dual resonators. From the catalytic converter, the exhaust gas goes through 1 resonator, U turns through another resonator, and then out the exhaust tip. This gives each turbo its own full 3" outlet. With the U-turn and 2 resonators, this should create a clean sound. Utilizing this with the stock catalytic converters will give some increases over stock while keeping you emission clean and CEL free. The exhaust is designed to work with the OEM or with AP's 3. 5" carbon fiber tips. As tested on our Mustang AWD Dyno, we compared the 991 Turbo with the new Agency Power muffler to the stock muffler system. The muffler freed up exhaust flow quite a bit gaining almost 40 ft per lbs of torque at 4100rpm. This is the peak torque and where the turbochargers come on full blast. Horsepower peak gain was approximately 20 awhp at 5000rpm. The new Agency Power mufflers weigh in at just 8. 05lbs where the stock is 24. 5lbs, saving you up to about 16. 45lbs off the rear end. Providing even faster turbo spool up and larger top end gains is possible with the combination of our Agency Power headers and race pipes.