Reinforced exhaust valves Nissan GT-R R35 VR38DETT

Nissan engines covered

The VR38DETT is the 3.8 litre twin-turbo V6 with 24 valves fitted to the Nissan GT-R R35 since 2007, including the NISMO versions.

Its two cylinder heads carry 12 exhaust valves. The reinforced standard-size valve has a 32.15 mm head, a 5.95 mm stem and a 92.0 mm overall length. With two turbos right after the cylinder heads, these valves live permanently in very hot gases.

SUPERTECH and FERREA reinforced exhaust valves

On the VR38DETT, two turbos mounted right against the cylinder heads keep the exhaust side in intense heat, almost without respite. Measured in the metal, the valve head then passes 1,000 °C, where an unboosted engine stays between 760 and 870 °C. Roughly three quarters of this heat flow out through the seat; the guide takes around 20 %. For steel, the EV8 family serves as the benchmark: 550 MPa at 600 °C, but only 300 MPa at 800 °C. Any gain in boost pressure, revs or torque adds to this heating, and the head ends up fatigued, warped, unable to close its seat.

Reinforced valves therefore rely on nickel superalloys. SUPERTECH uses Inconel, which holds 860 MPa at 730 °C and 554 MPa near 815 °C, some 85 % better than EV8 steel near 800 °C, in solid form (NEVI-1060, NEVI-1062) or hollow and sodium-filled (NEVI-1062-HS), the sodium carrying heat from the head towards the stem. At FERREA, the Competition Plus series comes in Super Alloy, another nickel material built for turbo engines; the brand claims 20 % higher strength at high temperature and a seat that wears 25 % more slowly.

At +1 mm, the head grows to 33.2 mm from both makers, with stem and length unchanged. Burnt gases escape sooner, fresh air finds its way in more easily and power climbs. Afterwards, every one of the 12 exhaust seats is cut to suit this larger diameter.

Exhaust valve technical specifications

Valve fitting

Before refitting the springs, compare the valve lock groove with the collets you reuse.

At 32.15 mm the seats stay as they are; with a +1 mm version, the 12 exhaust seats are cut to the diameter of the new head.

All these valves keep a 6 mm stem and a 92 mm overall length: the original guides are fine if they are within tolerance.

Technical guide

Our brands

	SUPERTECH is based in California, in Silicon Valley, where for over 30 years it has produced valvetrain components for racing engines. Every valve it makes, be it stainless steel, titanium or Inconel, is studied individually for one engine and then refined alongside first-rate tuners.
	FERREA Racing Components, a company launched in 1978 by Horacio Ferrea with the help of Daniel Urrutia, makes its valves at two sites, in Florida and Argentina. Stainless steel, titanium, nickel superalloys: its parts equip competition engines on every continent.

How to choose

Kept in place by the retainer, the collets grip the stem by its groove. Two questions remain: should the head be enlarged, which means machining the seats, and which material suits the boost you are aiming for?

When reinforced valves become necessary

• Turbo boost raised (Inconel version recommended)
• Camshafts replaced by sharper profiles or reinforced valve springs fitted
• Maximum revs pushed higher
• Heads rebuilt for track, time trials or drag racing
• Original valves marked, worn or burnt

Vehicle compatibility

OEM part number (exhaust valve): 13202-JF00A, 13202-JF00B, 13202-JF00C, 13202-JF00D

Don't forget the inlet valves

With the VR38DETT heads off, take the opportunity to replace the inlet side too, with a new set of valve stem seals. On the inlet side, the GT-R has its own page: