What goes into building a quality exhaust system?

What is the production process like?

What materials should be used and why?

These are all questions I thought about before my employment at A.W.E. Tuning.

I’ve learned a great deal about exhaust systems in my time here and wanted to pass on some of the information to you. Allow me to show you some behind the scene aspects of what it takes to actually manufacture an A.W.E. Exhaust System. Bear in mind that even before we get to the manufacturing stage, a great deal of time and effort has been spent in the prototyping phase between sound, power, and fitment testing.

Raw Materials:

Mild or aluminized steel is typically used by muffler shops because of the low raw material cost. This low grade material has a tendency to rust and chip. Ever see a rusted out exhaust on the side of the road? Chances are it was made of mild or aluminized steel.



All of our exhausts are composed entirely of stainless steel tubing. Stainless steel is used because of its resistance to corrosion and stability at elevated temperatures. It won’t rust like mild or aluminized steel and will most likely outlast your car. In short, it’s the right material for the job.

Further, our mufflers use a combination of stainless steel and composite acoustic packing materials to minimize part throttle droning.


Mandrel Bends:



We bend all the T304 Stainless Steel Tubing used in our B6/B7 exhausts with a German made CNC mandrel bending machine. A mandrel bender differs from a generic tube bender in its ability to support the tube internally while the bend is being created. This prevents the tube from crimping or collapsing at the bend, ensuring a consistent diameter of the tube all the way around the bend which is critical for optimum air flow.


TIG Welding:

TIG welding is a much slower process than MIG welding. A TIG weld is no stronger than a MIG weld. Why then is the majority of our B6/B7 exhaust TIG welded? TIG welds are much cleaner than the equivalent MIG weld. Where MIG welds will resemble pools of liquid metal a TIG weld will appear like a running river.

An example of a quality TIG weld:



When we weld an item, like the resonator section of an exhaust, it is filled with Argon. This is called “backpurging” and is done to keep contaminants and air out of the weld bead. Such a pure weld creates a stronger joint and also provides a smoother internal finish which is better for flow.


Fixture Table:

A Fixture Table (or jig) can be considered the heart of the production process. It is a precision piece that we use to ensure all our systems fit together perfectly.

It takes time to develop a fixture table that can reliably be used to fabricate production items. Length of tubing, angles of joints and placement of flanges all must be exact to ensure proper fitment and alignment. One wrong measurement could throw off the fitment of a complete system. We take great care when designing our fixture tables

Here is a picture of a completed straight pipe section of our B6/B7 S4 Exhausts in the fixture table:



Once the individual components have been assembled and double checked for correctness, everything gets placed in its respective spot on the fixture table. A member of our Fabrication Department will then carefully weld the components together.

Polishing:



We polish the components of our B6/B7 Exhausts before they are assembled in the Fixture Table. Polishing is the most labor intensive portion of assembling these systems. It takes a great deal of time, but the luster our systems have afterward is well worth it.

Final Finishing:

During final finishing, all welds are cleaned up, the sharp edges are removed from the flanges and all brackets/hangers are attached to the system.

Here is Frank, one of our expert fabricators, attaching hangers onto the Resonator Section of a B6 S4:





Final Inspection:

Before an exhaust is sold, it must pass a final inspection.

We go over the entire system to make sure the welds are complete, hangers are straight and flanges are smoothed and chamfered. Once it has passed inspection the exhaust is cleared for sale.



This wraps up our tour of an A.W.E. Tuning exhaust system. I hope you found it insightful.

Feel free to ask any questions you may have regarding our production process or our exhaust systems.

Cheers

 

Nice writeup Alex!

 

I want your exhausts!