There is no secret as to why a turbo catted pipe is an important piece to any aftermarket exhaust setup. Drivers looking for solid performance gains know that their stock equipment isn't going to cut it. Factory exhaust systems are not intended to provide the air flow necessary for maximum horsepower. Invidia offers turbo catted pipes that go a long way towards giving your car exhaust an improvement in flow rate that delivers fast results.
Invidia high flow front pipes work to demonstrate increased airflow distribution throughout your entire exhaust system. OEM piping is narrow, holding back gases from being able to flow freely. The stock catalytic converter adds to this restriction. What an Invidia high flow front pipe does is help free up exhaust gases by eliminating the restriction caused by the cat. It is a direct replacement. Turbo catted pipes have 200 cell cats that guard the exhaust from spitting out smelly exhaust fumes, despite the removal of the converter. Using a wide 60mm diameter, Invidia high flow front pipes effectively free up the choked gases for a quick increase in horsepower coming from your Boxer engine.
Going with turbo catted pipes over the OEM configuration will unveil a jump in HP and torque that you will notice at the top end. This modification is most often used by owners of the Subaru BRZ or Scion FR-S and both models have undergone various dyno tests to conclude the amount of horsepower a turbo cat pipe is responsible for. The exact number varies due to extenuating circumstances such as the age of the cars at the time the tests were conducted and also if they featured any other performance exhaust parts. It is agreed by most that a turbo catted pipe adds on an extra 5-7 horsepower. There is also a noticeable improvement in throttle response, even in BRZ models otherwise void of custom parts.
Constructed of SUS304 stainless steel, Invidia turbo catted pipes are both rust and corrosion resistant. This is an important attribute, as many stock and custom car exhaust components are instead fashioned from aluminized steel or cast iron. Both of these materials are vulnerable to rusting and staining from constantly being in the trenches and exposed to exhaust gas. Stainless steel is commonly used for aftermarket exhaust parts because it is able to stand up to the heat emitted through the pipes and on top of their surface(s).
Invidia sizes and shapes their catted front pipes using mandrel-bending. When each pipe is formed and the diameter is determined (in this case, 60mm), the pipe is then placed in the mandrel. From here, the technician inputs the degrees of the bends that the pipe will show. What this process does is guarantee that where the bends are placed is not only of optimal efficiency, but also displays a perfect fitment and accounts for the ground clearance of the car. The goal of a performance pipe is to minimize the amount of bends, not have more of them. That means whatever bends are enacted are as subtle as can be. Mandrel-bent pipes deliver an accurate fitment with the best possible exhaust flow.
The flanges on each pipe are stainless steel, as well, and CNC-machined. Flanges that have slim bracketing are at risk to cracking. They also cannot be of a universal size. Different exhaust parts may have different flanges, making fitting them to each other while using gaskets sometimes very difficult. Computer-numeric-controlled machining is a process that Invidia uses to manufacture many of their parts, including pipe flanges. With CNC-machining, the flanges are digitally-measured according to the size of the pipe, the car the tuner high flow exhaust is designed for, and to fit to and in place of any stock exhaust parts.
When it comes to installation, high flow pipes come with a gasket, two nuts, two bolts, and instructions. Some suggest replacing older OEM gaskets prior to installing (if necessary). However, taking out the cat in favor of a turbo catted pipe deems your car ineligible to pass inspection in many states. Because of this issue, most of the time this is a customization employed by drivers who use their models in off-road situations such as racing competitions or demonstrations. It is recommended to consult your local motor vehicle bureau before installing a turbo catted pipe.