Reinforced inlet valves SUBARU FA20F

SUBARU engines covered

The FA20F is Subaru's 2.0 litre direct injection turbo flat four with 16 valves. From 2013 it powers the WRX GJ, the Forester XT SJ, the Impreza GJ and the Outback BS 2.0 DIT, from 241 to 272 hp.

It has 8 inlet valves, Subaru part number 13201-AA640, held by 13210-KA031 collets. Raised boost, sharper camshafts or a higher rev limit load them well beyond stock use.

SUPERTECH reinforced inlet valves

The inlet valve lets in the air compressed by the turbo, closes on its seat on every cycle and slides constantly in its guide. It runs between 400 and 550 °C: at 600 °C an original chrome-silicon steel only holds 250 MPa against 500 MPa at 500 °C, 50 % of its strength lost.

SUPERTECH forges the SIVN-1049-2 from EV8 stainless steel, which keeps 650 MPa at 500 °C and 550 MPa at 600 °C, 30 % and then 120 % more than the original chrome-silicon steel. Its stem is relieved under the head (undercut) and its head has a back cut, two machining steps that clear the air path.

It comes in standard size, with a 34 mm head, a 5.46 mm stem and a length of 105 mm: the inlet seats keep their diameter.

Inlet valve technical specification

SIVN-1049-2-8: EV8 stainless steel, undercut stem and back cut.

Fitting details

In standard size the valve fits without cutting the seats; lap it onto a seat in good condition.

Technical guide

The brand offered

SUPERTECH Performance has been designing valves, springs and retainers for racing engines in San Jose, California, for more than thirty years. Each batch goes through ultrasound, X-ray and laser checks, and each part number is developed for a given cylinder head with engine builders.

How to choose

A single part number is offered for this engine:

When reinforced valves become necessary

• Boost raised after a remap
• Sharper camshafts or stiffer springs
• Higher rev limit
• Cylinder heads rebuilt for circuit or rally
• Worn or marked original valves

Compatible vehicles

OEM part number (inlet valve): 13201-AA640