Reinforced exhaust valves Ford Focus RS ST Mustang 2.3 EcoBoost

Ford engines covered

The 2.3 EcoBoost is Ford's 2.3 litre, 16-valve direct injection turbocharged four, fitted to the Focus III RS from 2015 to 2018, the Focus IV ST since 2019, the Mustang VI since 2014 and the Everest II since 2025.

Its 8 exhaust valves work constantly in the gases that feed the turbo; raised boost pushes their temperature and load higher still.

FERREA and SUPERTECH reinforced exhaust valves

On a turbocharged engine, the metal of the exhaust head goes beyond 1,000 °C, against 760 to 870 °C naturally aspirated. About 75 % of the heat leaves through the seat and 20 % through the guide. An EV8 family steel is the benchmark: 550 MPa at 600 °C, no more than 300 MPa at 800 °C; beyond that, the head fatigues, distorts and no longer seals properly.

FERREA offers its Super Alloy for this engine, a nickel-based alloy intended for turbo engines, at standard size and +0.5 mm. SUPERTECH adds two Inconel valves, a nickel-based superalloy that keeps 860 MPa at 732 °C and 554 MPa at 816 °C, about 85 % more than EV8 steel around 800 °C; their hollow sodium filled stem, liquid from 97.8 °C, carries heat from the head to the guide.

With the +0.5 mm oversize, the head goes from 30 to 30.5 mm: burnt gases leave more easily, and the 8 exhaust seats are machined to the new diameter. The FEVI-2502F-HS-8 goes further, to 31 mm (+1 mm), with the same seat machining.

Exhaust valve technical specifications

The F2370P and the FEVI-2501F-HS-8 are standard size; the F2371P is +0.5 mm and the FEVI-2502F-HS-8 +1 mm. The SUPERTECH valves have a flat head and a single lock groove.

Valve fitting

Before refitting, check that the collets match the groove of the chosen valves.

At 30 mm the seats stay at their size; with a 30.5 or 31 mm head the 8 exhaust seats are machined to the new size.

The FERREA valves have a 5.46 mm stem and a 104.75 mm length; the SUPERTECH valves a 5.45 mm stem and a 104.7 mm length. A sodium filled valve is never drilled or cut.

Technical guide

Our brands

	FERREA, founded in 1978, makes its valves in Florida and Argentina. For the 2.3 EcoBoost it offers its Super Alloy at standard size and +0.5 mm.
	SUPERTECH Performance, a Californian maker of competition valves for more than thirty years, completes the range with two sodium filled Inconel valves, at standard size and at +1 mm.

How to choose

Size comes first, then material:

When reinforced valves become necessary

• Boost raised by remapping
• Larger turbo
• More aggressive camshafts
• Track and acceleration
• Cylinder head rebuild with marked exhaust valves

Vehicle compatibility

OEM part number (exhaust valve):

Don't forget the inlet valves

An open 2.3 EcoBoost cylinder head is the right time to replace the inlet valves and the valve stem seals too.