Process West Intercooler: What Actually Changes on the GR Yaris
The stock intercooler on the GR Yaris is a plastic tank-and-tube unit sitting behind the bumper. It works fine for daily driving. It gets hot when you push the car hard, and the intake air temperatures climb fast. That causes timing pull and power loss. The Process West unit replaces that whole assembly with a fabricated aluminum core and a larger crossflow design. I installed one on my GR Yaris about two years ago and ran it through a normal track weekend. The first session got IATs into the low 140s Fahrenheit after three pulls on the dyno. That's normal for the stock setup. After the swap, the same run stayed in the upper 90s. The car felt sharper off idle too, especially with the tune I was running.
Unleash The Beast How Process West Intercooler Transforms Your Gr Yaris
The main thing going on here is thermal mass and airflow efficiency. The factory unit has a small core packed between the radiator and the bumper opening. Heat soaks into it during repeated runs, and the plastic housings don't help. Process West makes their cores from welded aluminum extrusion. The internal fin structure is more open than the stock design, which means less restriction and better heat rejection. The end tanks are also billet or TIG-welded, not injection-molded plastic. Here's what most people miss. A bigger intercooler isn't automatically better. If you run one that's too large without supporting the rest of the system, you can actually get slower throttle response because the charge air takes longer to travel through the extra volume. The Process West unit is sized to match the Yaris's 1.6-liter inline-three flow rate, which is why it doesn't feel sluggish. The OEM core is undersized but also low-volume. The PW unit sits in a sweet spot. Installation isn't hard but it does require some disassembly. You remove the front bumper cover, disconnect the intercooler piping, and drop the stock unit. Process West includes new silicone couplers and bolts. Make sure you check the fitment of the up_pipe bracket, because on some builds the factory bracket clears fine and on others it rubs slightly against the new core end tank. I had to loosen the bracket mounting bolt, tap it back with a rubber mallet, and retorque it. Took about ten minutes to fix.
One thing worth noting is the temperature sensor placement. The GR Yaris has an intake air temp sensor on the charge pipe near the throttle body. The stock intercooler cools the air right at the front, so the sensor reads cool temps early in a run but those temps climb as the core soaks. With the Process West unit, the sensor reading is more consistent across repeated pulls, which matters if you're running a tuned ECU that uses IAT for timing corrections. On a stock tune, the car will still pull timing somewhat, just less aggressively because the temperatures stay lower. You'll want to pair this with a proper tune. Running the car on stock map with a much more efficient intercooler is fine, but you're leaving boost and timing on the table. The Yaris's engine management is pretty conservative by default. A tune that takes advantage of the lower charge temperatures will make more power throughout a session instead of just at the beginning. The downsides are minimal but worth mentioning. The unit is more expensive than the stock replacement options from generic brands. You also need to keep the front end clean. The open core design traps bugs and road debris faster than the plastic unit, so plan to remove the bumper and wash the core every few track days or heavy street use. A front mount filter screen helps but can add a small amount of restriction.
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If you're only doing occasional Sunday drive stuff, this upgrade is overkill. But if you're track day regular or live somewhere hot and run the car hard on the street, the Process West intercooler is one of the highest-value bolt-ons for this car. The GR Yaris is a tight package and space is at a premium, so getting an intercooler that actually fits and performs without requiring fabrication is rare. This one does.
