Top Contender – Street Performance Intercooler R&D, Part 2 – Production Sample and Test Results

Turbo boxer has a nice ring to it. It’s perfect for one of those boxing games found in a retro arcade. Then again, Top Contender probably fits best, but I called dibs on that. Really though, Turbo boxer is a great descriptor for the WRX’s powerplant. Much like those retro arcade games, tuning and modding your Subaru is all about finding the right combination for the hardest hitting punch, with the intercooler being an integral part of that proverbial button sequence.

We last left you with our master plan like some sort of Bond villain divulging our scheme for world domination before our dashing secret agent makes his daring escape. Unlike those campy nemeses, we followed through. From metal framework and 3D printed end tanks to full aluminum glory, let’s take a look at the WRX Street Performance Top-Mount Intercooler in the flesh. Well, in the metal.

Not only will our new intercooler fit with the stock engine cover, but you have the option to install the Mishimoto ducting for a more direct airflow to the core.

I would venture to guess that most of you aren’t here to ogle the outward appearance of our new intercooler design, but rather to see if it can walk the walk. Fair enough. Let’s get right down to business. Our intercooler testing consists of three different parts, and the first of those is to determine the flow of our new design. Cooling vs. flow is a fine line that has to be walked when creating performance intercoolers, specifically when it comes to the internal fin pitch. Something too tight will lead to better cooling but flow worse than the stock unit. Too loose and the hot charged air flows straight through without a chance to transfer the heat. Let’s take a look and see how our design stacks up.

The big question here: With the 12% increase in airflow through the intercooler over the stock unit, were cooling properties sacrificed for the sake of dissipating heat? To find out, we had to load up our donor WRX on the Dynapack system for the other two sections of our testing.

For part two of intercooler testing, we run a series of single dyno pulls to determine two things. The first is to find out if there are any extra ponies picked up after the install of the bigger and badder design, and then we look for a snapshot of the outlet temperature difference. Our donor vehicle was already sporting a Cobb intake map powered by a V3 Accessport in tandem with an aftermarket intake and cat-back exhaust, which is right in the sweet spot for our Street Performance Top-Mount.

Now, I would also venture to guess that a majority of you don’t solely drag race your WRXs, so repelling heat-soak is the key characteristic in these tests. To perform this test, our engineer basically stacks a series of power pulls back-to-back, without the chance for the intercooler to breathe in between. This give a true look as to how well the core can dissipate the heat under stressful conditions, and we can let the data speak for itself int this case.

Even with the outlet temperatures peaking at over 250°F, our intercooler’s outlet temperatures practically flatlined throughout our heat-soak test.

While we measured the heat, or lack thereof, traveling through the different intercoolers, we also kept records of other perimeters that owners of turbocharged vehicles might be concerned with. Namely, we measured the drop in psi from one end of the core to the other. A drop is to be expected when it comes to increasing the cooling capacity of intercoolers, but minimizing that drop is key for the best performance. We already noted that our engineer was able to balance cooling properties with airflow in this design, but how did that effect pressure. Well, when all was said and done, our top-mount had an average pressure drop of 1.2 psi, which is lower than the stock intercooler.

Finding that right combination for the best power move is tricky. It takes plenty of practice and patience. Our Street Performance Intercooler for your WRX is like hitting the right button sequence in that combination and nailing the uppercut. The best part is that this intercooler is now available for your WRX, so get yours today!

2015+ Subaru WRX Street Performance Top-Mount Intercooler

Still not sold? Worried about your specific tune or want to hear what some 3rd party testers say? That’s fine, so did we. Make sure to stay tuned for some 3rd party testing results from Area1320 Motorworks coming soon.

Thanks for Reading!

-Nick

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