12 May Fabricating Porsche 911 Exhaust : Part 3

For the Final segment of our 3 part series, we will talk about the work that goes into Fabricating Porsche 911 Exhaust systems on our 991 Carrera S project. In the last blog, we talked about the X-pipe and our secret of creating a great exhaust system. This blog will cover all the work that goes into creating a custom stainless steel exhaust for this 991 911 Carrera S.

Spacing can be tight in the back of a 911 Porsche, so fitment is absolutely crucial. With the design routing roughly mapped out and the material sizes in hand, we start test fitting pieces into place. Sections of straight pipe are placed into location with tape to verify routing. If the piece is correct, it is then removed and cleaned. If we need to slightly change direction of the tubing, the change is noted and made using various fabrication equipment. We cut or sand the tube into the desired angle, and bring back to check alignment. Before a piece is tack welded into place, it is cleaned meticulously.

To build a visually appealing system, you need to use high-quality materials and really take your time. Cleaning and fitment are critical, and it needs to be with the best material possible. We only use high-quality stainless steel when building our custom exhausts. Not only does stainless steel have the corrosion resistance for us to put a lifetime warranty on our work, but it allows us to make some truly beautiful pieces. When properly prepped, stainless steel used in our fabrication provides a uniform flow on the inside, maximizing the total gains possible. With this Carrera S, as with all of our exhaust builds, we aim to have the piece look as beautiful as it sounds.

Once the exhaust routing is finalized and the layout of the pieces tacked together, the final welds are started. We spend a large amount of time processing the raw pieces of pipe so that they match up as perfectly as possible prior to the actual welding taking place. Not only does this make for a great looking weld, but also great for exhaust flow. With no overlapping edges (and thus, no excess weld penetration) that can lead to turbulent exhaust flow, we can ensure the exhaust will make optimal power while having a clean sound. We further minimize interior flow disruption by fully back-purging all of our welds with inert gasses preventing oxidization of the inside of the pipe. Oxidization creates a pile of slag that adds turbulence, cutting down on power and altering the sound. Back-purging also adds an extra bit of strength and rigidity to the weld and the system as a whole.

Lastly, adding the exhaust hangers ensures the system remains secured to the vehicle. However, before we can finalize fabrication, we run the vehicle to heat it up to operating temperature. The thermal expansion of stainless steel can change the location of the exhaust by up to half and inch. By waiting to fabricate hangers till after we see how the exhaust expands and contracts, we can be sure that the system won’t develop a condition where it hits the body, or melts the bumper when hot. Once the expansion has been analyzed, we then utilize the factory mounts in the hangar construction so the system can be easily uninstalled if the vehicle ever needed to be returned to stock.

“Refined Violence”

With all of the panels back on the vehicle, it was time to turn our attention to the exhaust valve control. The valves are activated via vacuum that is supplied by a switch we located on the fuse box panel. The idea was to have two operational modes for this 911: Mode 1 would allow cruising with the sound remaining more or less at factory levels (this also tends to please discerning spouses); Mode 2 is activated via a switch that turns this car into something we describe as “refined violence”.

Fabricating Porsche 911 Exhaust systems isn’t easy, and We here at Fluid take pride in our work. After all, this garage was not founded on the principles of making a quick buck and disregarding quality for a better bottom line. There’s more to building a proper, powerful, and aesthetically pleasing exhaust system than just lining up pipes and welding them together. There’s a good deal of thought, precision, and effort that goes into every custom Fluid MotorUnion exhaust, and Mike’s 911 was no different. With all of the positives that we have promoted in building a custom exhaust, you maybe wonder if there is a catch somewhere. Well as we always try to show transparency and honesty with our customers, I will tell you there is a catch. Being a small company, we have decided to make sure that our fabrication quality is held under our extreme scrutiny; therefore, we have decided not to just pump these out quickly and cheaply. This may mean long wait times, and our pricing is usually a bit more than something that’s mass produced. Please understand, however, that to us, our reputation is everything. Creating an exhaust you love is extremely important to us. We care about every single car that rolls through these garage doors, as we believe in the passion involved in motoring. If you care enough about your car to bring it to us, we want to make sure that care is reciprocated and evident in our work.