Those looking for a GrimmSpeed ceramic downpipe are interested in sustained, professional-level performance. Loosening up exhaust is almost always one of the first priorities for a Subaru owner. The reasoning behind this is simple. Although Subaru designs and assembles turbo models, they do not account for them adequately within the exhaust system. The factory pipes are not wide enough in diameter to properly usher airflow. They are also underwhelming when it comes to durability.
Naturally, for drivers who want more acceleration out of their vehicles, supplementing the turbo is of high importance. A GrimmSpeed ceramic downpipe plays a significant role in making that happen. It works due to how the exhaust is configured. Stock pipes have catalytic converters, which are responsible for filtering out harmful, smelly exhaust fumes. The converters perform this duty with a catalyst. Dirty airflow passes through the pipe, through the catalytic converter and is then filtered. This process somewhat “cleanses” the fumes. However, it is also restrictive. Not only is exhaust given a detour, but it is also passing through a narrow OEM tube. Exhaust is choked back just enough to halt any potential for elevated performance.
Swapping out the stock part in favor of a GrimmSpeed ceramic downpipe opens up the airflow. It does this mostly due to its wider diameter. Since the tubing is roomier, airflow is freed up and can travel faster. The GrimmSpeed ceramic downpipe also replaces the factory catalytic converters, effectively taking out the additional hindrance. When done correctly and with no other mods present, a Subaru turbo downpipe offers about 15-20 extra horsepower. That number might be an approximation, but it is representative of the median increase experienced by most.
Every GrimmSpeed ceramic downpipe is molded, bent, and machined using T-304 stainless steel. The employment of stainless steel is intended for improved durability and resistance to corrosion. It is meant to be both a higher performing part as well as a heavier one. Finally, the most attractive option is whether to have your GS Subaru downpipe given a coating of ceramic paint. Doing this presents a couple of critical benefits.
As exhaust is given free reign a substantial amount of heat is created. Heat inside the pipe on one hand, is good. It helps the exhaust move easier. On the other, too much of it can cause collateral issues. When the tubing becomes too hot, heat can radiate through the surface, affecting nearby components. It also means heat is escaping from the confines of the pipe, thus displaying a counterproductive quality. Engine bay temperatures rise enough as it is. Greater exhaust flow piles on, sometimes enacting a critical increase during intense driving.
This is where a GrimmSpeed ceramic downpipe comes in. The outside coating provides the initial layer of heat dissipation, cutting down secondary transfer. Without it, the surface of the part radiates heat. But the inside coating is just as crucial. Here is where temperatures are at their highest. The ceramic paint prevents heat soak from the exhaust infiltrating the tubing. It keeps the air heated properly without it escaping. The overall result is more efficient airflow, quicker turbo spooling, and of course, more horsepower.
The material of the GrimmSpeed ceramic downpipe matters almost as much as the coating itself. When applied to a high quality metal (in this case, 304 stainless steel), the paint improves exhaust performance and lengthens the serviceable life of the part. Some drivers will wrap their GS Subaru downpipe, but this is usually not necessary. In fact, it could actually be detrimental. Moisture can (and often does) find a way between the wrap and the pipe. Being that the Grimmspeed part is made of stainless steel and hosts a ceramic coating, wrapping it is inconsequential at best. In the event there is moisture buildup between the wrap and the surface, there could be a risk of damaging the coating.
Another factor that makes a ceramic coated downpipe popular is the look. Most other sections of the car exhaust are steel or iron. Since many Subaru modders enjoy displaying their parts, having a sleeker, more unique look is part of the attraction. Each GrimmSpeed ceramic downpipe is given a black coating at headquarters and is thoroughly inspected prior to shipping out. In addition, they also offer ceramic paint for other sections. When browsing for Impreza exhaust accessories check to see if there is an option for ceramic coating prior to placing your order.