An important aspect of a performance exhaust is how the exhaust tubing is bent.  Whereas some companies will market "performance", these claims can be somewhat inflated.

There are two common methods of exhaust tube bending.  The most common form, usually found at the local Midas or Meineke exhaust shops, is pressure bending.  This is when a tube is put into a machine and bent around a die.  Depending on how much pressure is put onto the tube, around the die, determines the actual bend.  This form of exhaust "fabrication" is very commonplace when replacing mufflers on Ford Taurus with 150,000 miles or when replacing the muffler on a Chrysler minivan.

Mandrel bending has become the standard in aftermarket systems, since it most closely matches how factory exhausts systems are produced.  Everything from the $299 Honda Civic exhaust with the coffee can tip, although commonly produced in China or Taiwan, has mandrel bent tubing.  This allows the original diameter of the exhaust tubing to retain its shape throughout the entire system, even in the bends.

As shown in the pictures to the right, a pressure bent tube can actually decrease in size in the bend, from 2.25" to 1.97".  Of course, the tubing of a "performance exhaust" can only be as large as the smallest diameter, and thus, in this case, can be much smaller than advertised.

Rogue Engineering's exhaust systems are produced entirely in North America using the latest exhaust manufacturing methods such as mandrel bending, TIG welding (vs. MIG welding) while surpassing performance and quality of many competing products produced overseas (or who knows where).

Mandrel vs. Pressure Bending

Unbent section of tubing
(shows 2.25")

Pressure bent tube is now less than 2" in diameter

Mandrel bent tube retains its full 2.25" diameter