Special INOX (Cooper-Ring) Headgasket for 2.5L TFSI engine to reduce compression ratio and up to 84mm bore size. Thicker TTRS/RS3 head gasket to give a bigger piston to head clearance. The TFSI 2.5L engine has a very small quench that is riski in over rev situations. Once the piston hits the head, the rod bearings wipe out, and results in a damaged crank shaft. This thicker gasket is the strongest and best gasket available for the 2.5L TFSI engines! Features: 1,4mm thickness (0,9mm is OEM) Compression ratio from 10:1 on 9,6:1 lNOX Rings Gasket (best sealing) For extrem high boost (also NOS suitable) Bore size up to 84,00mm Plug & Play (no modifications needed on head or block) Perfect for our Mahle pistons Fits this models: Audi TTRS 2.5L TFSI Audi RS3 2.5L TFSI Mounting instruction: The grooves in the INOX rings must show to the head. Bartek the 2.5L-TFSI-Expert recommends the ARP studs . Manufacturer Information about the manufacturer BAR-TEK BAR-TEK Motorsport GmbH Im Rauschen Auel 3, 51491 Overath-Brombach, Germany info@bar-tek.com