Once your custom Subaru uppipe is in place and ready to go, performance instantly improves. Sport compact racers often concentrate on overhauling the stock exhaust system. That is because most car owners see the OEM setup as constrictive and underwhelming. In order to glean the most results, the addition of a custom Subaru uppipe is a common occurrence. Designed to fit your exhaust as if it came from the OEM, this pipe encourages a higher degree of airflow while accounting for potential heat expansion. GrimmSpeed manufactures their custom Subaru uppipes for WRX, STI, LGT, and XT models.
It can be difficult to manage proper exhaust airflow when the goal is more horsepower. A Grimmspeed flex up pipe makes it easy. It helps to understand what this part is responsible for. A Grimmspeed flex up pipe essentially connects the exhaust to the turbo. The stock pipe can do this, but does so with a catalytic converter. The Grimmspeed flex up pipe does not have the cat for two main reasons. First off, the catalytic converter can be incredibly restrictive to exhaust flow. Secondly, it eliminates the possibility of grimy particles finding their way from the cat to the turbo. With a Grimmspeed flex up pipe, you are liberating exhaust while protecting your turbo from incidental contamination or damage.
Heat also plays a role. One of this mod’s biggest attributes is its flexibility, called an “uppipe flex joint.” Particularly for race models exhaust heat can become a factor. While keeping Subaru race exhaust accessories cool is always a priority, a high amount of heat has to be accounted for. An uppipe flex joint is created specifically to handle this heat coming from the exhaust flow. GrimmSpeed crafts each joint from 321 stainless steel with an interlocking liner. What this does is handle the expansion created by the hot exhaust as well as the contraction when heat is dispersed. Thus, the uppipe flex joint presents a smoother exit for airflow while helping the exhaust maintain adequate density.
Quality material can always be counted on. Grimmspeed Impreza up pipes are crafted from T-304 stainless steel (except the interlocking liner). The flanges are intended for extra strength and precise mating to other parts, measuring in at 1/2” thick. They are also CNC-machined to make installation cleaner and easier. All GS race pipes come with hardware and instructions.