Dynamometer: Raceline 224X Dynojet
Just prior to our Power Pages testing, the FR-S was introduced less than a week ago at local dealerships, yet we somehow managed to get our grubby paws on a “Whiteout” colored Scion to spin on the dyno. Plenty of aftermarket manufacturers have already begun developing numerous parts in anticipation of the car’s debut as evidenced over the last few months. From superchargers to body kits, the 86/FR-S has been received with open arms and that’s a good sign for both the car and our industry. The unmistakable styling cues and sleek exterior design of the FR-S is a welcoming invitation to many who have become accustomed to the average consumer cars being sold in the United States that portray the look and feel of your average grocery getter. Weighing in at less than 2,750 pounds (MT) the FR-S is not only lightweight, but it’s also designed with a well-balanced chassis that had been engineered to perform in considerable fashion both on and off the track.
By far the biggest controversy of this car has been the 4U-GSE engines. The flat-four boxer engine was a joint collaboration with Toyota and Subaru. The factory-rated 200hp boxer engine enables the FR-S to achieve excellent weight distribution, the lowest CG ever for a production vehicle, but the biggest question on every tuner’s mind was how would this direct injection engine fair on the dyno? Upon installing our first aftermarket part and conducting a few dyno pulls, we were quickly educated on the fact that the FR-S 4U-GSE boxer engine doesn’t take kindly to bolt-on modification. It’s as if the factory ECU seemingly pulls out a bright red stop sign every time you tamper with this engine. For those looking to generate more horsepower with your FR-S, continue reading along, you will see through our extensive dyno testing that simply slapping on aftermarket parts without tuning offers minimal gains at best.
With the car strapped to the dyno, we made a series of pulls as the FR-S laid down consistent figures on the average of 160.3 hp and 132.7 lb-ft of torque to the wheels. We also monitored the engine’s air/fuel ratio, which ran approximately 14.9:1 from 1,300 to 3,000 rpm at low-end, 13.1:1 from 3,200 to 6,200 rpm in the midrange and richened up significantly at the top end (12.0:1 and lower) from 6,300 to redline at wide open throttle—an indication that the ECU was tuned significantly rich throughout the powerband to preserve the motor for longevity.
HKS Super Hybrid Drop-In Panel Filter
The HKS Super Hybrid Filter is a direct replacement panel filter designed to fit into the factory FR-S airbox. This maintenance-free filter helps to increase airflow and filtration over the stock unit. Using a three-layer dry filter, the super hybrid filter separates and catches dust particles and optimizes airflow direction through the filter while the replaceable element eliminates the need to re-oil the filter. The first layer catches larger dust particles while the second and third dual-density polyurethane layer filters out smaller particles. Why test a panel filter rather than a cold air intake, you ask? The answer is simple. Our inaugural testing commenced during a time when no short ram or cold air intakes were available due to the FR-S’s week-old release on the market. Panel filters were already available and plenty abundant due to the filter’s shared design with the 2011-and-newer Scion tC.
The FR-S 4U-GSE boxer engine loves to breathe. Unfortunately the factory panel filter’s restrictive cotton gauze design chokes the engine’s performance. For testing purposes, we also dyno’d the factory airbox without a filter, which lost 2 hp and 2 lb-ft of torque in the process. As the air flows over the MAF sensor, removing the filter from inside the box creates air turbulence and improper airflow over the MAF, causing the ECU to compensate for the changes and attributes to the power loss.
Dyno testing the HKS filter revealed an increase in power and torque throughout the powerband, with the largest gains of 5 hp and 4 lb-ft of torque at 6,600 rpm over our previous run. Consistent gains of 3 hp and 3 lb-ft of torque were seen from 6,000 to redline over our baseline run. The air/fuel ratio was recorded to run slightly leaner with the new intake filter coming in at 12.8:1. The leaner air/fuel condition was an accrediting factor to our increased horsepower.