Author Topic: GrimmSpeed Top Mount Intercooler, Splitter, Y-Pipe - Product Release  (Read 1625 times)

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Offline GrimmSpeed

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GrimmSpeed Top Mount Intercooler
MSRP: $679.99

GrimmSpeed TMIC Product Information

  • 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 Motor Damage Due To Foreign Matter

General Design

There are two primary considerations in the design of an intercooler: maximum heat transfer and minimum pressure drop. 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. 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 575hp before it’s likely that a FMIC might be better suited for your system. 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 welder, Josh, hand TIGs 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.


Performance is a difficult subject when discussing a top mount intercooler that can be used in many different systems, often times with different goals. For that reason, we’ve opted to use primarily stock-turbo cars running higher boost. This particular 2.0l TD04 car is running full exhaust (catted), a GrimmSpeed EBCS and a 19psi tune. First, we tested pressure drop to ensure that our aggressive core design didn’t negate its benefits with a massive pressure drop. The graph below shows boost pressure in the inlet and outlet end tanks, as well as the calculated pressure drop and a trendline. Because of sampling rates and the nature of the pulsing system, you’ll notice that there is a great deal of noise in the pressure drop measurements. What’s important is the trend and as you can see, the maximum recorded pressure drop is just above .2psi with an average of around .1psi. Data was collected using a DATAQ DI-148U sampling a pair of ProSense pressure transmitters at 240Hz. Next, we tested inlet and outlet temperatures using a pair of K-type thermocouples and high frequency multimeters. What we found is that with a stock turbo, the OEM WRX TMIC seemed to keep up OK until 5000rpm or so. At that point, the efficiency of the OEM TMIC drops off very quickly. As we continued doing pulls, performance of the OEM TMIC degraded very quickly and the GrimmSpeed TMIC refused to budge, no matter how much heat we put into it. The graph below shows the post-IC temperatures for the GrimmSpeed TMIC vs. OEM TMIC. Note that these pulls were both completed after the same warm-up procedure (a series of shorter pulls) but before the OEM TMIC was fully heat soaked (and just about useless). Lastly, the third graph shows the calculated efficiency for these two top mounts based on temperatures taken from the same two pulls. This graph shows that even before it’s heat-soaked, efficiency of the OEM TMIC begins to drop significantly after 3800rpm.

Of course, power figures vary from dyno to dyno, and actual power gains will vary from setup to setup. What's shown below are the actual before and after power curves for a Forester XT running a vf39 on an auto trans. After the first pull, the car was tuned for the GrimmSpeed TMIC, to take advantage of the additional cooling and much lower pressure drop. At 5000rpm, the car picked up an additional 35whp and 37ftlb.


  • 02-07 Subaru Impreza WRX
  • 04-13 Subaru Impreza STI
  • Subaru Forester XT
  • Baja Turbo

MSRP: $99.99

GrimmSpeed Y-Pipe Product Information

Tired of installing and reinstalling your OEM or aftermarket top mount intercooler using your awful, hard-plastic OEM y-pipe? Just bought an aftermarket or STI TMIC that require an STI y-pipe to fit? Want to stop choking your TMIC with those tiny plastic baffles? Maybe you're just looking to freshen up your engine bay with a touch of GrimmSpeed style. Well, there's something for everybody with the GrimmSpeed Y-Pipe Kit.

  • Two-Piece Casting - Allows for maximum adjustability/flexibility
  • Extra-Thick Flanges - Prevent heat and vibration from cracking casting
  • Machined Flanges - Ensures a leak-free seal, every time
  • 5-Ply High-Grade Silicone Couplers - Smooth interior to maximize airflow and minize restriction
  • Heat Resistant Reinforcement - Couplers keep their shap, even at high boost levels
  • Stainless Steel T-Bolt Clamps - Rust-proof construction with locking nuts

TMIC Splitter
MSRP: $199.99

GrimmSpeed TMIC Splitter Product Information

Tired of popping your hood only to have that ugly OEM Splitter remind you of how badly it deprives your fancy TMIC of the cool, ambient air that it requires? Perhaps you’ve upgraded to an STI scoop and want to really make use of that extra air? Maybe you’ve already got an STI splitter but want to squeeze every ounce of performance out of your top mount. After frustrations with this and more, the GrimmSpeed team has the real solution. Well, five real solutions. Introducing, the GrimmSpeed TMIC Splitter lineup.

  • 70% Increase in flow capacity to your TMIC - Massively improves your TMIC's ability to remove heat
  • Maximizes TMIC Efficiency - Lowers TMIC outlet temps, enables more aggressive tuning
  • Designed for even flow distribution - Forces entire core work to cool the hot charge air
  • CAD design and simulation - Ensures both fitment and function
  • CNC Laser Cut 5052 Aluminum - Resists fatigue due to heat and vibration
  • Durable DuPont Black Powdercoat - Protects splitter with an OEM finish
  • Custom EPDM Rubber Gasket - Provides excellent seal and longevity
Contact us with any questions!


Offline Longlivetheride

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Re: GrimmSpeed Top Mount Intercooler, Splitter, Y-Pipe - Product Release
« Reply #1 on: June 17, 2013, 11:56:10 am »
Group Buy?

Offline LilDrunkenSmurf

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Re: GrimmSpeed Top Mount Intercooler, Splitter, Y-Pipe - Product Release
« Reply #2 on: June 17, 2013, 11:59:37 am »
They just ran one, 50 ppl on NASIOC.
If the sea was vodka, and I was a duck.
I would swim to the bottom, and drink my way up.
But the sea isn't vodka, and I'm not a duck.
So give me the vodka, and stfu.
If you're having forum problems, I feel bad for you son, I got 99 problems but your post ain't one.

Offline GrimmSpeed

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Re: GrimmSpeed Top Mount Intercooler, Splitter, Y-Pipe - Product Release
« Reply #3 on: June 18, 2013, 08:37:14 am »
Group Buy?
Yep, we just ran one on NASIOC. No worries though, as it's priced very aggressively. You'll be able to find these at RSD and the like for around $599. We're currently out of stock, but will be back with a much larger production run in a month or so. I believe RSD is accepting backorders, if you're interested in getting your mitts on one as soon as possible!

Matt Beenen


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Re: GrimmSpeed Top Mount Intercooler, Splitter, Y-Pipe - Product Release
« Reply #4 on: June 18, 2013, 09:33:14 am »
That's one big core!

Thanks Matt for spreading the love on this one