F20C vs FA20 Comparison
Honda released the S2000 in 1999, powered by the screaming F20C engine. In 2013, Toyota and Subaru launched the FRS & BRZ, along with the FA20 boxer engine to the masses.
The Honda was designed as a tribute to the 50th anniversary of the company, and was as much a demonstration of everything the company stood for as it was a car. It was priced to compete with the BMW Z4 and was never intended as an everyman's car.
The Scion FRS & Subaru BRZ were designed from the outset as an affordable rear wheel drive coupe with excellent handling dynamics.
Let's explore the specific differences.
In the following dyno image, taken of a GT86 and a S2000 on the same day, we can see these differences play out. Ignore the blue and green lines and look at the orange and red lines above.
Below 6,100RPM, the FA20 produces more torque and hence power under the curve. My theory on the torque dip is engineered into the engine to meet emissions and fuel economy requirements over the lifecycle of the platform.
While both have variable valve timing systems, the way they work is completely different. The AVCS system in the FA20 seems to be optimised for low to mid-range torque. The ECU commands a solenoid which advances or retards the camshaft rotation by up to 35 degrees. Coupled with direct injection, it produces a nice amount of low-end torque for a 2.0L engine.
As the Toyota engine has moves past peak torque, VTEC switches the cam profile, and the boost in torque coupled with the high RPM takes the Honda engine to another class.
Honda's VTEC has a more aggressive secondary camshaft profile that you can see in almost every F20C dyno sheet - a 'jump' in torque as the engine passes the engagement RPM, producing a great amount of high-end torque for a 2.0L engine.
Toyota had a similar system on their 2ZZ engine, which appeared on the Toyota Celica and Lotus Elise. Because the FA20 is a boxer engine, implementing such a system would incur a weight penalty as there are two cylinder heads on the engine, as opposed to only one on the F20C.
Honda's engine shines as bright today as it did 13 years ago. Simple bolt on modifications and tuning can take that engine to 135hp/l and beyond. The FA20 seems to be limited by a lack of reliable camshafts and the inherent purpose of the valvetrain design.
The Toyota motor is still young, and here's hoping that there will be some radical innovations in the cylinder head to add more fire to the top end.