Reinforced exhaust valves Porsche 996 Turbo GT2 M96.70

Porsche engines covered

The M96.70 is the turbocharged 3.6 litre flat-six fitted from 2000 to 2005 to the Porsche 911 type 996 Turbo, Turbo S and GT2, coupe and cabriolet, with 420 to 483 hp depending on version.

It has 12 exhaust valves, two per cylinder, just upstream of the turbochargers: boost pressure and long periods at full load expose them to very hot gases.

FERREA reinforced exhaust valves

Each opening plunges the exhaust valve into gases that have barely burnt. The metal of its head reaches 760 to 870 °C on a naturally aspirated engine and passes 1,000 °C on a turbocharged engine like this one. About 75 % of the heat leaves through the seat, nearly 20 % through the guide. An EV8 family steel keeps 550 MPa at 600 °C but only 300 at 800 °C: the head distorts, fatigues and sealing is lost.

FERREA makes both valves in its Super Alloy, a nickel-based alloy reserved for the hottest exhausts, and supplies them with a single groove, in standard size and oversize.

The F2272P takes the head from 32 to 33 mm while keeping the 5.95 mm stem and the 109.1 mm length: the flow area increases, burnt gases leave the cylinder faster and the engine gains power; the 12 exhaust seats are machined to this diameter.

Exhaust valve technical specifications

Both sets are 109.1 mm long with a 5.95 mm stem; only the head changes.

Valve fitting

FERREA pairs these valves with its 6° K10092 collets: check that they fit exactly in the single groove of the stem.

Use the strip-down to fit new valve stem seals and check the clearance of each guide around the 5.95 mm stem.

Regrind the exhaust seats with the new valves; the 33 mm F2272P requires them to be machined to its size first.

Technical guide

Our brand

FERREA, a valve maker founded in 1978, produces in Florida and Argentina. For the M96.70 it offers two Super Alloy references: F2271P in standard size (32 mm) and F2272P enlarged by 1 mm (33 mm).

How to choose

Both sets share material and groove; only the size sets them apart:

When reinforced valves become necessary

• Raised boost pressure or larger turbochargers
• Engine remapping
• Repeated track sessions
• Burnt or leaking exhaust valves
• Cylinder head rebuild

Vehicle compatibility

OEM part number (exhaust valve):

Don't forget the inlet valves

With the cylinder heads removed, it is the time to replace the M96.70 inlet valves and valve stem seals as well.