Reinforced exhaust valves VW Golf 4 New Beetle Polo 1.8T 20V

VW engines covered

At Volkswagen, the 20-valve 1.8T turbocharged four-cylinder powers the Golf IV and its GTI version, the New Beetle and the Polo GTI 9N, with 150 or 180 hp depending on the engine code (AGU, AQA, ARZ, AUM, AUQ, AWP, AWV, BBU, BJX, BKF and others).

Its five-valve-per-cylinder head devotes two of them to the exhaust, 8 exhaust valves in all, with hydraulic tappets. The Volkswagen part 058 109 611 E has a 29.9 mm head, a 6 mm stem and a length of 103.9 mm; it is the first part to suffer the extra heat of a remap or a higher flow turbo.

SUPERTECH and FERREA reinforced exhaust valves

Sitting just upstream of the turbine, the exhaust valve of a turbocharged engine sees its head metal go beyond 1,000 °C, against 760 to 870 °C on a naturally aspirated engine. It only sheds that heat by contact: roughly 75 % through the seat and 20 % through the guide. For the original steel, the EV8 family is used, dropping from 550 MPa at 600 °C to 300 MPa at 800 °C; when too hot, the head fatigues, distorts and ends up sealing poorly.

At SUPERTECH, the AEVN-1103 is black nitride stainless steel; the AEVI-1103, AEVI-1103S and AEVI-1106S are Inconel, a nickel alloy still at 860 MPa at 732 °C and 554 MPa at 816 °C, nearly 85 % above EV8 steel around 800 °C; the AEVI-1103S-HS and AEVI-1106S-HS move to Nimonic with a hollow stem holding sodium which, molten at 97.8 °C, transfers heat from the head to the stem. At FERREA, the F1554P and F1555P have 3 grooves.

The AEVI-1106S, AEVI-1106S-HS and F1555P widen the head to 30.9 mm instead of 29.9 mm: the cylinder empties faster towards the turbo and fills better on the next cycle, for a power gain; the exhaust seats must then be recut to that diameter.

Exhaust valve technical specifications

SUPERTECH note: the single groove AEVI-1103S, AEVI-1103S-HS, AEVI-1106S and AEVI-1106S-HS are fitted with KPR-6S/7 collets.

Valve fitting

The collets follow the number of grooves: SUPERTECH pairs the KPR-6S/7 with its four single groove versions.

With a 29.9 mm head the exhaust seats stay as they are; at 30.9 mm they are cut to the new size.

For sealing, the Volkswagen part number of the valve stem seals is 036 109 675 A.

Technical guide

Our brands

	SUPERTECH Performance has been designing racing valves and valvetrain parts in California for more than thirty years. For the Volkswagen group 1.8T 20V it covers nitrided stainless steel, Inconel and sodium filled Nimonic, at standard size as well as +1 mm.
	FERREA was founded in 1978 by Horacio Ferrea and Daniel Urrutia and manufactures in Florida and Argentina. On the 1.8T 20V, its 3-groove valve comes at standard size and with a head one millimetre larger.

How to choose

The groove determines the collets; the size then decides the work on the seats:

When reinforced valves become necessary

• Higher boost pressure after a remap (Inconel version recommended)
• Fitting a higher flow turbo
• Changed camshafts or valve springs
• Regular track driving
• Cylinder head rebuild with tired exhaust valves

Vehicle compatibility

OEM part number (exhaust valve): 058 109 611 E

Don't forget the inlet valves

If the 1.8T 20V cylinder head is off, take the opportunity for the inlet valves: