Mike Bonanni posted on March 11, 2009 22:00
The stock cats have a small 46mm inlet with a 60mm outlet, with tiny under 2" tubing. The Berk parts are a much bigger 2 1/2" or 68mm in diameter all the way through with smooth mandrel bends to really uncork the system in this area. We think that the large diameter downpipes are the part mostly responsible for the gains in power that the Berk parts see.
The Berk parts are high quality pieces featuring 100% 304 stainless steel construction. The cases, tubes and flanges are all high grade 304. The transition from the tube to the cat is gusseted for additional strength. For tuning convenience, bungs for a wide band A/F O2 sensor are located in both downpipes before the cats. For an easy installation and a leak free seal a factory exhaust manifold compatible gasket is provided. Usually most aftermarket downpipes don't tool up a gasket for oddball OEM flanges and recommend red silicone seal in this area. Modern cars won't tolerate leaks before the rear o2 sensors or they will trigger check engine lights and Berk has proactively addressed this with their gasket.
What are some potential problems from using high flow catalytic converters?
There are a few potential problems that you may run into when replacing your car's factory catalytic converters with aftermarket ones. The first is violation of smog laws. Some states prohibit tampering with or replacing your car's factory catalytic converters with aftermarket parts. Basically check your local laws before installing if you are worried about this.
Second is the possibility of your car's check engine light coming on. On the 370Z, like most cars, there are a set of oxygen sensors that monitor the effectiveness of the catalytic converters and send those readings to your car's factory computer (ECU). If these sensors detect readings that are outside of a certain range, it will trigger your check engine light. On the Berk Technology down pipes, the oxygen sensors are positioned after the catalytic converters in the stock position using a 6mm sampling hole so this should not be a problem.