Reinforced inlet valves SUBARU BRZ FA20D FA20C

SUBARU engines covered

The BRZ's FA20 is a naturally aspirated 2.0 litre Subaru flat-four with 16 valves and two camshafts per head. Coded FA20D then FA20C, it delivers 200 to 208 hp in the BRZ coupé (ZC6) built since 2012.

The engine has 8 inlet valves with a 5.46 mm stem. Their length changed during production: 103.3 to 103.45 mm on early engines, 105 mm afterwards, so you choose the length of the valves removed. A supercharger, a turbo or sharper camshafts load them far more than standard use.

SUPERTECH and FERREA reinforced inlet valves

The inlet valve opens on every cycle to let air in, closes by striking its seat and slides in its guide, dozens of times per second when the engine revs high. It runs between 400 and 550 °C; at 600 °C the chrome-silicon steel of a standard valve keeps only 250 MPa of strength against 500 MPa at 500 °C, a 50 % loss.

The SUPERTECH valves are EV8 stainless steel, with a stem thinned under the head (undercut) and a back cut that free the air path; EV8 holds 650 MPa at 500 °C and 550 MPa at 600 °C, 30 % then 120 % more than the original steel. The FERREA valves have a flat head: the Competition Plus valves for early engines, stainless with a chrome stem, gain 20 % in hot strength and fatigue resistance and extend seat life by 25 %; the 6000 series valves are EV8 stainless steel; the FERREA valves for 2015 engines are special alloy.

Both brands supply the standard size (35 mm head) and the +1 mm size (36 mm). With a larger head, the flow area at the seat grows: filling improves and the engine gains power, provided the 8 inlet seats are cut to 36 mm.

Inlet valve technical specification

SIVN-1050-2-8 and SIVN-1052-2-8: long valves for 2014 and later engines.

F2357P*8, F2358P*8, F6337*8 and F6338*8: 2012 to 2014 engines, 6.5 mm stem tip. F2379P*8, F2381P*8, F6349*8 and F6350*8: 2015 engines, 8.2 mm stem tip.

Fitting details

The +1 mm size requires inlet seats cut to 36 mm; at standard size the valve fits seats in good condition, simply lapped in.

Choose the length from the valves removed: 103.3 or 103.45 mm on early engines, 105 mm afterwards.

Technical guide

Our brands

	Based in San Jose, California, SUPERTECH Performance has been designing racing valves, springs and retainers for more than thirty years. Its parts go through ultrasound, X-ray and laser inspection, and each part number comes from work with engine builders on a specific cylinder head.
	FERREA Racing Components started in 1978 in Fort Lauderdale, Florida, founded by two engine builders of Argentine origin. Each valve is forged as one piece from bar stock, then CNC machined from end to end; the brand supplies NASCAR and drag racing.

How to choose

The groove is the recess machined near the end of the stem, in which the collets hold the retainer; here, size and length make the choice.

When reinforced valves become necessary

• Supercharger or turbo added to the naturally aspirated engine
• Sharper camshafts or stiffer springs
• Higher rev limit
• Cylinder head rebuilt for circuit, drift or rally
• Tired original valves or seats already reground

Compatible vehicles