Reinforced exhaust valves Audi S2 RS2 2.2 20V turbo 3B ADU

Audi engines covered

The 2.2 20V turbo five-cylinder powers the Audi S2 (code 3B, 220 hp, 1990 to 1992) and RS2 (code ADU, 315 hp, 1994 to 1995), the latter developed with Porsche. Its four-valve-per-cylinder head comes from the competition 20V quattro.

It carries 10 exhaust valves, run by hydraulic tappets. The Audi part 027 109 611 B measures 28.0 mm at the head, 7.0 mm at the stem and 98.2 mm in length. Higher boost, richer fuelling or sustained driving: on these often tuned engines, the exhaust side is the first to take the rise in temperature.

SUPERTECH and FERREA reinforced exhaust valves

On the S2 and RS2, the 2.2 20V five-cylinder sends its exhaust straight into the turbine, and all 10 exhaust valves sit in that stream. The metal of their heads, which stays between 760 and 870 °C when there is no turbo, rises here beyond 1,000 °C. It cools by contact: the seat takes up nearly 75 % of the heat, the guide about 20 % through the stem. EV8 steel serves as the benchmark for the stock valve: 550 MPa at 600 °C, only 300 MPa near 800 °C. Beyond that the head fatigues, bends and the seat no longer closes cleanly.

SUPERTECH covers three materials on this engine. Its stainless versions are VWEVN-1034, black nitrided, and VWEVN-1035 in EV16. Its Inconel versions, VWEVI-1034F, VWEVI-1035 and VWEVI-1037, rely on a nickel superalloy that keeps 860 MPa at 732 °C and 554 MPa at 816 °C, about 85 % above EV8 near 800 °C. VWEVI-1035-HS pairs Nimonic with a hollow stem filled with sodium, liquid from 97.8 °C, which draws heat away from the head. FERREA answers with its 6000 series, F6027 and F6028, made from EV8 stainless steel, their stems hard-chromed.

Several references enlarge the 28.0 mm stock head: 28.5 mm for VWEVN-1035, VWEVI-1035 and VWEVI-1035-HS, 28.6 mm for F6028, 29.5 mm for VWEVI-1037. More diameter means more area for spent gases: the cylinder purges better toward the turbo, takes a denser charge and power follows. Each exhaust seat must then be cut to suit the new head size.

Exhaust valve technical specifications

The VWEVN-1034, VWEVN-1035, VWEVI-1035, VWEVI-1037 and VWEVI-1035-HS have a dished head; the VWEVI-1034F has a flat head.

Valve fitting

For this cylinder head family, the SUPERTECH valves are fitted with the KPR-VW7-S collets, the VS-VW7-E seals and the GDE-VW8V-7A guides.

At 28.0 and 28.1 mm, close to the Audi size, the exhaust seats are checked; from 28.5 to 29.5 mm they are cut to the chosen diameter.

The original stem seals carry Audi part number 027 109 675.

Technical guide

Our brands

	A Californian designer of racing valvetrain parts for more than three decades, SUPERTECH offers the widest range for the 20V five-cylinder: stainless, Inconel and sodium-filled Nimonic, from the Audi size up to a head enlarged by 1.5 mm, in flat or dished form.
	FERREA dates back to 1978 and to its two founders, Horacio Ferrea and Daniel Urrutia. The valves are made in workshops located in Florida and Argentina. For the 2.2 20V turbo the brand supplies two valves from its 6000 series, one at stock size and one at 28.6 mm, both made of hard-chromed EV8 stainless.

How to choose

Fix the size first, since it sets the work needed on the cylinder head, then the material: stainless for use close to stock, Inconel or sodium-filled Nimonic once boost and temperature climb clearly.

When reinforced valves become necessary

• Remap with raised boost pressure (Inconel version advised)
• Bigger turbo or more efficient intercooler
• Camshafts or valve springs replaced
• Regular track sessions under heavy load
• Head reopened for worn or pitted exhaust valves

Vehicle compatibility

OEM part number (exhaust valve): 027 109 611 B

Don't forget the inlet valves

Removing the cylinder head of the S2 or RS2 2.2 20V turbo? Replace the five-cylinder's inlet valves at the same time; you will find them through the link below: