Naturally aspirated, flat four engine for Subaru and Toyota sports cars
By Dave Hagen
At the beginning of 2012, the joint Subaru and Toyota model was put into production. You know it as Subaru BRZ, Toyota 86 or Scion FR-S. This new, naturally aspirated, flat four FA20 engine was developed specially for these sports cars. It was built based on a FB20 cylinder block, modified into square bore/stroke ratio. The diameter of its cylinders and piston stroke is 86mm. Unlike the usual FB20, this motor uses new pistons, a new crankshaft, and the compression ratio was increased to 12.5:1.
FA20 engines use new heads with a direct injection system of the Toyota D4S, a variable valve timing system AVCS that is used on both intake and exhaust camshafts. Also, 4-2-1 headers are installed on this motor.