Since the owner of Project Z doesn't own a trailer, the car gets driven long distances on the street to and from track events. Therefore we wanted an exhaust that gave decent power without adding an obnoxious amount of noise. We also wanted as much power as possible. In other Z exhaust evaluations, it looked like twin exhaust systems seemed to make the most power on the Z33. DC Sports exhaust filled the bill nicely. It is a true dual systems beautifully fabricated from polished 304 stainless. The muffler features a dual path perforated straight through core for both cylinder banks for super low restriction, while the large can volume provides plenty of room for sound absorbing materials to help reduce the sound levels.
The DC Sports exhaust's tips are simple medium diameter polished 304 stainless. Nothing too gaudy or screaming rice. Of all the common automotive grade stainless alloys, 304 polishes well and holds a shine without tarnishing the best.
The twin tubes are 60mm, enough for quite a bit of headspace in the power development department and quite a bit larger than stock. All the welding in the DC Sports exhaust is TIG.
The all important Y pipe features a siamesed X pipe or crossover. This really helps out mid range torque and prevents the V6 puttering motorboat sound that dual exhausts that are acoustically separated have. In our experience most of the power to be gained in a naturally aspirated VQ motor is to be found in this area as the stock muffler section if fairly unrestrictive.
We replaced the stock cats with Berk Technology high flow racing cats. In our past experience Berk's high flow cats have produced the best results over others we have tested on Nissan VQ engines. The Berk units have a low restriction metallic core and all TIG welded stainless construction with crush free mandrel bends. The Berk cats have a bung for the OBDII rear O2 sensors as well as extra bungs before the cat brick for wide band O2 sensors used for tuning, a nice feature.
Perhaps the reason why the Berk parts make the best power is that they are large diameter all the way through. We have found other high flow cats that actually neck down internally. You can see the difference here. The Berk parts match our exhaust.