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Here is what a merged collector looks like on the inside. All of the exhaust primaries are smoothly tapered and blended together with maximum flow and minimal turbulence.
The stock Porsche collector is simply a dump box for the primaries. We feel that this is where much of the power gains over stock are made. The Dundon header also has larger in diameter and longer primaries than stock as well. The Porsche headers are shorter for better packaging to allow for bigger cats and the secondary side mufflers.
The Dundon Motorsports system is held together with high-quality stainless V-band clamps. This speeds assembly and disassembly of the modular exhaust system allowing quick reconfiguration from street to race versions of the exhaust.
We will be testing the street version of the Dundon Motorsports exhaust. The main difference is that the street version has a pair of high flow cats.
The only performance difference is that the race system has a few more hp in a narrow area between 5000 and 5500 rpm. This is because the front of the cat brick interferes with wave propagation at this rpm. Since you hardly see that RPM when driving the car hard with its close ratio PPK 7-speed transmission, the slight narrow power dip is unnoticeable to the driver.
The cat has a tig welded 304 stainless body, but the tubing is 321. The welds are quite clean and awesome looking.
Bungs for all four 02 sensors are placed before and after the cat.
