Reinforced inlet valves MITSUBISHI HYUNDAI Evo X Genesis 4B11T G4KF

MITSUBISHI and HYUNDAI engines covered

The 4B11T is the 2-litre, 16-valve, twin-cam turbo four-cylinder of the Lancer Evolution X (CZ4A), built from 2007 to 2014. Its aluminium block and twin-scroll turbo make it a sought-after base for tuning. The G4KF is the 2-litre 16-valve turbocharged four-cylinder of the Theta family. Hyundai fitted it to the Genesis Coupé (BK) from 2008 to 2014, with 209 to 277 hp depending on the version.

It has 8 inlet valves, originally 1010A220. Raised boost, sharper camshafts or a higher rev limit load them much harder than in standard form.

FERREA and SUPERTECH reinforced inlet valves

On every cycle the inlet valve opens to admit air the turbo has already compressed, then presses back onto its seat; at high revs this back-and-forth happens several dozen times each second, while the stem slides tirelessly in its guide. Its service temperature settles between 400 and 550 °C, and at that level a common chrome-silicon steel drops from 500 MPa at 500 °C to 250 MPa at 600 °C, a 50 % loss of strength. Extra boost, sharper cams or higher revs make those impacts, the wear and the heat more severe still.

For these engines FERREA offers two ranges. Its 6000 Series, made in EV8 stainless, retains 650 MPa at 500 °C and 550 MPa at 600 °C, that is 30 % and then 120 % more than a chrome-silicon steel. Its Competition Plus, stainless steel finished with a chromed stem, is credited with 20 % more resistance to heat and fatigue and a seat that holds up 25 % longer. SUPERTECH, for its part, supplies a stainless treated by black nitriding: the process hardens and polishes the surface, protects the stem in its guide and slows its wear over the miles.

In +1 mm form the head diameter grows from 35 to 36 mm, while stem and length remain identical to the original. Air crosses the seat more freely, the cylinders fill further and the engine picks up power, once all 8 inlet seats have been cut to that new diameter.

Inlet valve technical specification

F6294, F2175P and MIVN-1017 are standard size; F6295, F2176P and MIVN-1019 are +1 mm.

Fitting details

The FERREA valves have a single groove: use collets made for that profile, such as K10091, and check their seating before releasing the springs.

With the 35 mm head the inlet seats keep their factory size; with 36 mm the workshop machines all 8 seats to that diameter.

Technical guide

The brands offered

	FERREA Racing Components has operated in Fort Lauderdale, Florida, since 1978, when two engine builders with Argentine roots founded it. Everything is made on site: valves are forged in one piece from bar and completed by CNC before heading to NASCAR, drag racing or the track.
	SUPERTECH is headquartered in San Jose, California, where it has built racing valves, springs and guides for over thirty years. Each series is engineered around a precise cylinder head, examined using ultrasound, X-ray and laser, then signed off with tuners on track or at the strip.

How to choose

Here the choice starts with the size, which depends on your inlet seats, then the FERREA series; SUPERTECH offers one black nitride stainless version.

When reinforced valves become necessary

• Larger turbo or raised boost pressure
• Wilder cams or stronger valve springs
• Rev cut moved higher
• Head rebuilt for rally, circuit or time attack
• Mitsubishi or Hyundai valves damaged, or seats already refaced

Compatible vehicles

OEM part number (inlet valve): 1010A220

Related products

With the 4B11T head off, now is the time to replace its 8 exhaust valves too; you will find them in a reinforced version on this page: