2001-2007 Subaru WRX/STI Top-Mount Intercooler Part 3: Test Fitting and Data Collection
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Armed with a 3D printed prototype and a full day of test fitting, we were able to produce some very insightful renderings of how this intercooler was going to look. Initial flow testing and calculations showed that performance would be ideal for our target power range. After spending some time with Solidworks, Kevin produced the fantastic rendering you see below.
This design features smooth CFD- (computational fluid dynamics) tested cast end tanks for optimal flow. We designed several different core units with differences in fin height, fin pitch, bar size, and thickness. Our plan was to investigate the effects of these changes through testing on a variety of different vehicles running different boost pressures and making different horsepower numbers. Our cooler utilizes the factory bypass valve flange so an aftermarket unit is not necessary. Because of the single- entry end tank, a silicone S-shaped hose is needed to route air from the turbocharger to the intercooler. This hose will be included with the intercooler kit.
Soon we had a full prototype, and it looked fantastic. The castings are extremely accurate and the welds are perfect. It was now time to install this on our WRX and begin some initial testing. This first round of testing had been completed prior to the move to our new facility. Because of this we rented a dyno for the day at PSI Proformance in Lansdale, PA.
We started by removing the factory intercooler and preparing it for collecting data. We would be collecting some baseline data on the stock cooler to compare to the Mishimoto intercooler later.
As you can see we chose to tap both the throttle body side and the Y-pipe side of the intercooler so that we could capture both boost and temperature data at each point. This would allow us to see total pressure loss across the core, as well as the reductions in temperatures of this tube-and-fin cooler. The factory coolers are reasonably adequate for a stock or lightly modified WRX. Once the power and boost is increased, these coolers become fairly prone to heat-soak, which can rob a good deal of power.
All our data are collected using PLX devices that can capture a variety of measurements including exhaust gas temperatures, air intake temperatures (AITs), coolant temperatures, and vacuum/boost. This is a great tool that helps shed light on real-world results when installing our products.
After setting up the sensors and strapping our wagon to the dyno we were ready to make a few pulls. Everything went well and we captured some great data for the factory WRX top-mount intercooler.
After grabbing a quick lunch we were treated to the symphony of this gorgeous Ferrari F430, fitted with a new exhaust fabricated by the talented folks at PSI Proformance. Needless to say, it put our old wagon to shame.
Below is a first look at our prototype intercooler as we tapped each end tank for our sensors and prepared to make a few pulls.
After a few pulls of carefully monitored runs, we were rather pleased with the horsepower/torque that was produced. A collection of temperature and pressure data was acquired and would need to be compiled.
Our next round of testing was executed in the comfort of our brand new facility! Check back for fully installed images of this cooler and more dyno runs.