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GrimmSpeed Top Mount Intercooler Kit – 02-07 WRX / 04-21 STI / 04-08 FXT

GrimmSpeed Top Mount Intercooler Kit – 02-07 WRX / 04-21 STI / 04-08 FXT


The Grimmspeed TMIC can support 550+ HP with a low pressure drop of only .16 psi at 19psi. The core flow area is 120% larger than stock and flows 1580cfm. Parried with Grimmspeed Y-Pipe and splitter kits you get one of the best performing TMIC on the market.





General Design

There are two primary considerations in the design of an intercooler: maximum heat transfer and minimum pressure drop. Unfortunately, one causes the other, so finding a perfect balance requires a detailed understanding of the intended application, some serious engineering power and the highest quality manufacturing processes. Fitment and quality are also critically important to ensure that the most safety-critical part of your turbo system is up to the task every time your foot hits the floor. We began by laser scanning an OEM TMIC to plot the mounting points and space claim in CAD with pinpoint accuracy. At the same time, we designed a custom bar and plate core with overall dimensions, fin density and fin types that would provide the insane heat transfer area we require with minimal flow restriction. With core size nailed down, we got to work designing end tanks that offered smooth flow, perfect fitment and even distribution of the hot charge air through the core. Countless revisions were tested in flow simulation before we finally found exactly the characteristics that we wanted. From there, 3D printed prototypes were used to confirm fitment and we began work on manufacturing details in preparation for verification testing and production.


The core of any top mount intercooler is the beating heart of the beast. The intercooler cools your hot charge air in two different ways. The first is by reducing temperature by transferring heat from your hot, compressed air by conduction through the fins of the intercooler. The second is from a small pressure drop due to the flow restriction in the fins. The idea when you’re selecting an intercooler is to find one that results in an overall increase in air density. Rather than designing the largest possible core, or the core with the highest possible fin density, we created a well-rounded unit that’s designed specifically for Subaru’s making up to 550whp. That said, this particular core flows over 1500CFM and will support up to 575whp before it’s likely that a FMIC might be better suited for your system.

End Tanks

In our pursuit of perfection (there’s that p-word again), we learned a great deal about aluminum casting. If you’ve done similar research, you know that every aftermarket end tank that you’ve handled was cast from a one-time-use mold made of re-used sand. Not our style. In typical GrimmSpeed fashion, we stepped outside of the box and explored other options. We quickly learned that we had stepped into big boy territory. I’ll let the photos do most of the talking, but here’s the scoop. To achieve the quality, tight tolerances, pressure tightness and strength that we required, permanent mold casting became our only option. Each and every end tank is cast from the same CNC machined mold, ensuring not just dimensionally-perfect castings with an amazing surface finish, but also excellent repeatability. With this method, we have perfect control over both the internal and external contours of each casting. After casting, every single mating surface is precision machined for a leak-free finish and unbeatable fitment. We will not be outdone.


We designed tabs to be laser cut and CNC bent from 5052 aluminum, selected for its ductile nature, to ensure that the bending and welding processes don’t compromise their integrity. These will accept your stock TMIC bushings and offer plenty of adjustability for tweaked brackets and ‘creative’ turbo setups. After each component has been inspected, our welders hand TIG each and every assembly. From there, each assembly is pressure tested to 50psi and is thoroughly cleaned before it’s sealed up and prepared for shipping.

Splitter and Y-Pipes sold seperatly

Quick Specs

  • Smooth End Tank Internal Contours – Designed for maximum flow
  • Machined Throttle Body Connection – Tight, leak and trouble-free seal
  • Machined Flange Faces and Internal Bores – Maximum pressure-tightness and unrestricted flow
  • Permanent Mold End Tank Tooling and Casting – Allows much tighter tolerances and higher strength
  • Stainless Steel Threaded Inserts – Prevent cross-threading or damaged threads
  • High-Density, High-Flow Core – Optimizes heat transfer and minimizes flow restriction for turbo Subarus
  • Cleaned, Inspected and Sealed Prior to Shipping – Prevent Engine Damage Due To Foreign Matter
  • Includes GrimmSpeed Inlet and BPV Gaskets – The best in the industry!


Additional Information

Thermal Dispersant Coating

Raw Core, Black Thermal Coating


  • 2002-2007 WRX
  • 2004-2021 STI
  • 2004-2008 FXT


Installation Guide

Install Guide