12 May 991 Carrera S Exhaust : Part 2
In this blog of our 3 part series, we will talk about the goal of our 991 Carrera S Exhaust project. In the last blog, we talked about the “why” and “what” of our exhaust builds. In this blog we will talk about the “How”, or the secrets to getting that perfect sound as well as why the starting point of our 991 Carrera S Exhaust project, is the X pipe.
For the last nine years, Fluid MotorUnion has made a business out of fabricating custom exhausts for a wide variety of vehicles. When we design such an exhaust, we’re typically doing so for one of three reasons:
1) The current market offerings cannot cope with the power we are looking to run on our projects.
2) We are looking to amplify a particular sound attribute
3) Current aftermarket offerings do not meet the needs of the customer.
With Mike’s 911 we wanted the car to sound exotic, yet refined while also giving him the option for a “tamer” level at the flip of a switch. However, shopping around we could not find something that easily met our goals for his project. We knew what we wanted to accomplish, so we had to really analyze the system to determine how to achieve this in the most effective way possible. We decided that the center canister used to combine and muffle both engine banks would be the simplest way to accomplish our goals. We would need to redesign the system with only smooth merges and increase the diameter while making the routing of the factory exhaust bypass tubes more direct.
The most crucial part to a great sounding exhaust on any V-configuration engine is balancing the firing of multiple cylinder banks together. If this is not done properly, you can end up with an exhaust that sounds like two separate three cylinder engines. The best way to achieve this balance is by merging the separate banks as smoothly as possible. To accomplish this, we designed a gentle transitioning, high flowing X-pipe that allows the high-speed pressure wave from the exhaust pulse to be blended properly with the wave from the opposing bank. We call it our “Smooth Merge X-pipe”
We talked about x pipes before, so by now it would seem that our design is something like our “secret sauce” Using our special design “smooth merge x pipe” as a starting point, we first place it into its intended location and then see how all of the connecting pipes can best be routed. The X-Pipe takes up the most space, so by removing the factory center section and putting the X pipe in place as a starting point, we can ensure our system will have enough room.
To get the x pipe in place we have to first do some disassembly work on the 991 Carrera S Exhaust project. The rear bumper needed to come off in order to access and replace the center muffler. Taillights and spoiler also needed to be removed to access the bolts that hold the bumper cover onto the vehicle. Once the bumper cover, crash bar, and various exhaust shields were removed, we finally had access to remove the factory muffler. With the space cleared up, now the Fabrication can really get going!
Check back with us for the last part of our blog, and to hear how it all turned out!