Hot Hatch, Cool Turbo – Performance Intercooler for the 2023+ Toyota GR Corolla

As the Toyota GR Corolla enters its third model year, we’ve been hard at work expanding our lineup of performance products for the rally-inspired machine. The 1.6 liter three-cylinder G16E-GTS engine is the highest power-per-liter output of any Toyota road car engine with each cylinder responsible for 100 horsepower, boasting a total of 300 horsepower out of a remarkably small engine. The engineers at Toyota’s Gazoo Racing Division achieved this feat by pairing the G16E-GTS with a turbocharger capable of 26.3 psi of boost.

In the blog about our Performance Radiator for the GR Corolla we talked about how important cooling is for one of the most powerful three-cylinder engines in history. The same is true for the GR Corolla’s intercooler system. The turbocharger is a vital part of the GR Corolla’s performance, and when you’re driving the car how it's meant to be driven—setting lap times at the track, carving up and down mountain roads, or spirited cruising down your favorite backroad—that turbocharger is working hard, so it’s crucial to have an intercooler that works even harder. That’s why we set our sights on developing an intercooler designed to get the absolute most out of the GR Corolla.

Let’s take a look at what our engineers had in mind when they got to the drawing board.

• Create a performance intercooler that outperforms the stock intercooler
• Design the intercooler for a direct-fit application with the 2023+ Toyota GR Corolla
• Ensure our intercooler does not have significant pressure drop compared to the stock intercooler
• Use a bar-and-plate core design with cast-aluminum end tanks

Dan, our engineer, began by evaluating the stock intercooler to see where improvements could be made. The Toyota intercooler uses a 3.15” tube-and-fin design with 9 rows. After thoroughly scanning the GR Corolla’s engine bay with our FARO Design ScanArm to determine how much space we had to work with, Dan began his design for the new intercooler.

The result of his efforts was a much larger 3.94” thick bar-and-plate design with 12 rows. Compared to stock, our intercooler features a 52% increase in overall core volume and a 24% increase in fin surface area. Dan also incorporated anodized aluminum ducting to ensure optimal airflow through external fins, improving overall cooling effiency. Flow bench models showed our intercooler is 10% less restrictive compared to the Toyota intercooler.

These increases from our improved design indicated that our intercooler should outperform its stock counterpart, but “should” isn’t acceptable. Our next step was to get our intercooler installed and begin testing.

To obtain reliable data for comparison, we tested our 2023 Toyota GR Corolla with the stock intercooler and then with the Mishimoto intercooler. For both rounds of testing, we mounted the vehicle to our Dynapack™ dynamometer to perform consistent ramp tests.

With an ambient temperature of approximately 75°F the day of testing, the GR Corolla was brought to an operating temperature of 190°F by idling it on the dyno. Multiple runs were conducted with each intercooler until we were able to record consistent data. The car was kept running in between runs to maintain a consistent engine coolant temperature for each run. For the final round of tests, runs were made back-to-back with only 15 seconds between each round to simulate heat-soak conditions that might be experienced during aggressive driving.

Temperature

Thanks to the 24% increase in fin surface area and 52% increase in overall core volume, testing revealed the Mishimoto intercooler reduced the outlet temperature by about 38.5°F compared to the stock intercooler. The heat soak testing revealed an outlet temperature reduction of roughly 33°F, indicating that our intercooler is up to the task of demanding and aggressive driving conditions.

Pressure Drop

While monitoring temperatures, Dan also gathered data on inlet and outlet pressure to determine if he’d met his goal of minimizing pressure drop. A large decrease in boost pressure can cause strain on a vehicle’s turbocharger and add additional heat into the engine and intercooler, which can lead to a loss of horsepower in the short-term and a shortened lifespan for the turbo in the long-run. For a performance intercooler, this goal was crucial.

Testing revealed a success in meeting our goal. Data showed that our intercooler closely followed the pressure drop curve of the stock intercooler with a maximum deviation of only 1.1 psi, which is well within the acceptable range of pressure drop and won’t cause adverse effects to the GR Corolla’s intercooling system.

Power

The main purpose of a vehicle’s intercooler is to keep charge-air temperatures low. If those temperatures begin to climb, the vehicle’s ECU will reduce power to protect the engine. The idea behind a performance intercooler is that by cooling those charge-air temperatures more effectively while minimizing pressure drop, it’s less likely those temperatures will climb and the driver can maintain peak power in demanding conditions without damaging the vehicle.

Figures from our dyno confirmed a power increase with the Mishimoto intercooler compared to the stock intercooler. Data showed a max gain of 11.42 horsepower and 14.93 ft-lbs and a peak gain of 8.52 horsepower and 9.01 ft-lbs compared to the stock intercooler.

Not only does testing demonstrate that our intercooler is a significant upgrade over stock, the durable 4” thick bar-and-plate design is mated to cast-aluminum end tanks for serious dependability. This intercooler is truly a must-have for GR Corolla owners who’re looking to get the most out of the G16E-GTS without shortening engine or turbocharger’s lifespan.

With a superior design and proven to outperform OEM, we’re proud to add the Mishimoto Performance Intercooler to our line of offerings for the 2023+ Toyota GR Corolla.