Subaru devotees are usually interested in the improvement a steel Perrin uppipe offers. The reasoning is simple. Turbocharged Impreza models are not given a performance exhaust system. Drivers need to add parts that free up airflow in order to achieve better results. Installing an item such as a steel Perrin uppipe immediately upgrades an important portion of the exhaust. The engine gets to breathe more easily, initiating more boost and giving your car bigger horsepower potential. It is an easy way to replace the underwhelming stock configuration with a high quality answer. Everyone from professional racers to weekend hobbyists use steel Perrin uppipes in their WRX models.
Maintaining air density is a priority for mechanics. It is why WRX uppipes and other aftermarket components are used. Narrow pathways constrict the pattern of exhaust flow. This is due to slim tubing from the OEM. WRX uppipes sport a wider diameter (1.75” or 2”, depending on model year) that helps rush exhaust flow through. The effect is a higher velocity of flow that maintains an appropriate temperature. In turn, the exhaust coming from the headers and through the WRX uppipe is able to reach the turbo more efficiently, creating faster spooling. All around performance is also enhanced. If you are looking to get your car to a stage 2 setup, a WRX uppipe is a necessity.
Limit your expectations. A Perrin custom uppipe increases horsepower potential more than adding actual horsepower. In other words, it works best in conjunction with supplemental upgrades. That is not to say a Perrin custom uppipe will not offer a higher performance value. Installing one can generate an additional 5-7 HP. But when mated with pieces such as downpipes and equal length headers the difference is more pronounced. A full turbo kit configuration can add up to over 20 horses to your car’s capability. But in order to get the complete feel you will need a Perrin custom uppipe to build the foundation.
Two types of stainless steel are used in the construction of this piece. The tubing shown for each WRX racing pipe is 321 steel, which is recognized for its ability to withstand heat and maintain its integrity. The flanges, located at the end of each pipe, are made of 304 stainless steel and machined to 1/2” in thickness.