GrimmSpeed 2002-2007 Subaru WRX, 2004-2008 Forester XT Top Mount Intercooler With Y-Pipe

GRM090001.1 / GRM090024.1 - GrimmSpeed 2002-2007 Subaru WRX, 2004-2008 Forester XT Top Mount Intercooler With Y-Pipe

Cooling You Can Count On

When it comes to top mount intercooler performance, maximum cooling and minimum restriction are the name of the game. As air is compressed by your turbocharger, its temperature increases. Removing that heat helps increase air density and maintain consistent performance, especially as boost and driving demands increase.

The OEM top mount intercooler can handle normal use at stock boost, but as additional heat is introduced through higher boost or harder use, heat soak quickly becomes a limiting factor.

This complete kit pairs the GrimmSpeed Top Mount Intercooler with our cast aluminum Y-Pipe Kit, providing 2002–2007 WRX and 2004–2008 Forester XT owners with a complete, purpose-built intercooler system. The included Y-pipe, silicone couplers, clamps, and hardware provide the connections needed to install the GrimmSpeed TMIC while maintaining the airflow, fitment, and durability the entire system was engineered around.

QUICK SPECS:

• High-Density, High-Flow Core – Optimizes heat transfer and minimizes flow restriction

• Smooth End Tank Internal Contours – Designed for maximum flow

• Machined Throttle Body Connection – Tight, leak-free seal

• Machined Flange Faces and Internal Bores – Maximum pressure-tightness and unrestricted flow

• Permanent Mold End Tank Tooling and Casting – Allows tighter tolerances and increased strength

• Stainless Steel Threaded Inserts – Help prevent cross-threading or damaged threads

• One-Piece Cast Aluminum Y-Pipe – Precise fitment and smooth airflow

• Machined Y-Pipe Flanges – Provide a flat mating surface and leak-free seal

• 5-Ply High-Grade Silicone Couplers – Reinforced to maintain their shape under boost

• Stainless Steel High-Torque Clamps – Durable, rust-resistant construction

• Includes GrimmSpeed Inlet and BPV Gaskets

DESIGN:

There are two primary considerations in the design of an intercooler: maximum heat transfer and minimum pressure drop. One naturally affects the other, so finding the right balance requires understanding the application and engineering the entire system accordingly. Fitment and build quality are equally important to ensure reliable performance every time you put your foot down.

We began by laser scanning an OEM TMIC to plot mounting points and available space in CAD with pinpoint accuracy. At the same time, we developed a custom bar-and-plate core with the dimensions, fin density, and fin design needed to provide substantial heat-transfer area without introducing unnecessary restriction.

With the core dimensions established, we designed end tanks that provide smooth airflow, proper fitment, and even distribution of charge air through the core. Countless revisions were tested through flow simulation before 3D-printed prototypes were used to confirm fitment.

For this kit, the intercooler is paired with the GrimmSpeed Aluminum Y-Pipe. Inspired by the OEM design, the Y-pipe uses a one-piece aluminum casting engineered to distribute charge air evenly across the intercooler's inlet end tank. After casting, its flanges are machined for precise fitment and a reliable seal.

CORE:

The core is the heart of any top mount intercooler. Rather than simply designing the largest core possible or packing in the highest possible fin density, we created a balanced unit specifically for turbocharged Subaru applications.

The custom core flows over 1,500 CFM and was designed around applications making up to approximately 550 whp, with the ability to support roughly 575 whp before a front mount intercooler may become better suited to the system.

This approach provides the heat-transfer capability needed for demanding setups while keeping airflow restriction and pressure drop extremely low.

END TANKS:

To achieve the quality, tight tolerances, pressure tightness, and strength we required, we chose permanent-mold casting for the intercooler's end tanks.

Each end tank is cast from the same CNC-machined mold, providing excellent dimensional consistency, surface finish, and repeatability. This method also gives us precise control over both the internal and external contours of each casting.

After casting, every mating surface is precision machined for a leak-free finish and consistent fitment.

ALUMINUM Y-PIPE:

The included GrimmSpeed Y-Pipe replaces the need to source a separate STI-style Y-pipe when installing the GrimmSpeed TMIC on these applications.

Its one-piece aluminum casting provides smooth, consistent airflow without the distortion that can occur with less rigid designs. Thick, machined flanges provide strength and a reliable seal, while the included 5-ply silicone couplers are fiber reinforced to maintain their shape under higher boost levels.

The turbo-side 90-degree coupler is slightly oversized so it can be trimmed as needed for compatibility with a variety of stock-location turbo setups.

Together, the intercooler and Y-pipe create a complete system designed around airflow, cooling efficiency, fitment, and durability.

FITMENTS:

• 2002–2007 Subaru Impreza WRX

• 2004–2008 Subaru Forester XT

Options and Part Numbers

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