Process West Black Top Mount Intercooler w/ Shroud Subaru STI 2004-2005

Product Fitment:

2004-2005 Subaru STI

The Process West Top Mount Intercooler is engineered for Subaru STI owners who want improved cooling, reduced heat soak, and more consistent performance under hard driving.

Rather than simply using a larger core, Process West developed the intercooler, splitter, and Y-pipe as a complete system to maximize airflow and cooling efficiency.

Key Features & Benefits

• Optimized 90mm intercooler core
• Vehicle-specific splitter directs airflow across 100% of the core
• High-flow moulded silicone Y-pipe for even charge-air distribution
• Helps reduce intake temperatures and heat soak
• Supports more consistent power during repeated high-load driving
• Designed for efficient airflow through the factory-style top-mount location

Optimized Airflow

A larger intercooler is only effective when the ducting directs air across the entire core. Factory splitters can leave a significant portion of an oversized aftermarket intercooler without direct airflow.

The Process West splitter is sized specifically for the upgraded core, helping ensure the full intercooler surface receives ambient air.

90mm Core Design

Process West uses a 90mm core instead of the thicker 114mm designs found on some aftermarket intercoolers. Because air must turn sharply through the hood scoop before passing through a top-mount intercooler, excessive core thickness can increase airflow resistance.

The 90mm design balances cooling capacity with efficient airflow for improved thermal performance.

High-Flow Y-Pipe

The Process West silicone Y-pipe is engineered to distribute charge air evenly across the full width of the intercooler core, helping maximize its available cooling surface.

Proven Performance

Back-to-back testing on a 2005 Subaru WRX showed:

• Process West: 115.5 kW
• Factory intercooler: 107.5 kW
• Process West peak outlet temperature: 51°C
• Factory peak outlet temperature: 66°C

After three consecutive dyno runs, the factory intercooler reached 84°C and was still increasing.

During spirited road testing, the Process West system stayed below 43°C, while the factory intercooler reached 72°C and continued climbing.

What's Included

• Process West 90mm top mount intercooler
• Vehicle-specific intercooler splitter
• High-flow moulded silicone Y-pipe
• Mounting hardware and fittings