Subaru FA20 Engine

1. Specifications
2. Overview, problems
3. Performance tuning

Subaru FA20 engine specs

Subaru FA20 engine reliability, problems and repair

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. New sports naturally aspirated flat-4 FA20 engine was developed specially for this car. It was built on the basis of FB20 cylinder block, modified into square bore/stroke ratio. Diameter of its cylinders and piston stroke is 86 mm. Unlike usual FB20, this motor uses new pistons, new crankshaft, and the compression ratio was increased to 12.5.
FA20 engines use new heads with direct injection system of Toyota D4S, and also variable valve timing system AVCS is used on intake and exhaust camshafts. Also 4-2-1 headers are installed on this motor.
Such naturally aspirated engine was called FA20D or Toyota 4U-GSE and it showed 200 horsepower at 7,000 rpm, and torque 205 Nm at 6,400-6,600 rpm.
Except FA20D, there is also turbocharged version which is called FA20F/FA20E, better known as FA20DIT. This motor replaced EJ207 and EJ205.
FA20DIT engine uses non-forged pistons with the decreased compression ratio 10.6, its heads flow better, combustion chambers were improved in these heads and new camshafts are applied.
On the intake part there is the plastic intake manifold with TGV valves, and new turbo manifold is also used.
FA20 DIT engine uses twin scroll Garrett MGT2259S turbocharger. The maximum boost pressure is 15.9 psi (1.1 bar), and power is 272 HP at 5,600 rpm, torque 350 Nm at 2,000-5,200 rpm. Also, the over boost mode is available, at this mode boost pressure can increase to 22 psi (1.5 bar) for several seconds.
FA20 firing order is 1-3-2-4.

Subaru FA20 engine problems and malfunctions

1. FA20 rough idle. The problem is caused by ECU software. You need the new modified software for your ECU.
2. FA20 stalls. The problem with cam gear, which leads to the loss of pressure of engine oil.

For this engine it is necessary to use the best quality gasoline, and also to use original high-quality engine oil and change it twice more often than it is recommended. It will allow to keep reliability and will increase an engine resource.

Subaru FA20 engine tuning

FA20 Turbo. Supercharger

You are very lucky if you have turbocharged FA20 DIT, it will be easy for you to increase its power. For this purpose you need to buy only 3-inch aftermarket cat-back exhaust system, cold air intake, boost controller and adjust ECU. For cars with an automatic transmission it is desirable to have transmission cooler. It will give you 300-320 WHP. It will be excellent if you install aftermarket radiator and a frontal intercooler. It will be enough for active driving, but for receiving 400+ horsepower, you will need turbo kit.

Owners of BRZ and 86 are not so lucky as they need a turbo kit at once. It is possible to install cold air intake, straight exhaust system, to adjust ECU and to receive additionally 20-25 HP. That is all you need, you shouldn’t try to build high rev naturally aspirated, it is expensive and Subaru BRZ turbo will be quicker anyway.
The best choice for your Toyota 86 is supercharger kit, you should install it on FA20 stock internals. Such kits have max boost pressure 9-10 psi (0.6-0.7 bar), and it is enough to receive 280-300 horsepower. It is simple and optimal variant to receive great power.

To receive 350+ horsepower, you need the new fuel pump, fuel injectors, pulley and water/methanol injection. Don’t forget about transmission cooler and aftermarket radiator.
Instead of supercharger kit, you can install turbo kit on the basis of Garrett GTX3076R. Such kit is possible to install on stock internals and to receive 400 ++ WHP, and even up to 500 WHP (sport fuel).
FA20 stock internals keep more than 500 WHP, and if you use sports fuel and adjust ECU correctly, than over 600 horsepower.

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