Supertech High Performance Engine Valves, Springs, Valve Accessories, Pistons and Block Guards Supertech valve spring kit SPRK-H100DR/BM-16 Dual valve spring kit BMW 30,39kg/35,70mm (67 @ 35.70) Dual valve spring kit 30,39kg/35,70mm (16)SPR-H100DR/BM(16)+RET-K20A/T2+(16)SEAT-BM50 With the help of Supertech valve springs & titanium valve spring retainers, higher RPM/s can be run. It also eliminates valve flutter at high RPM/s. At high RPM/s, the rocker arms can break and the valve springs can jam. This can lead to engine damage! The Supertech valve springs have an extra adjusted spring rate. Advantages: The valve train becomes lighter thanks to the titanium valve spring retainers The motor revs up faster Higher motor RPM/s can be run The valve train becomes more stable during power increases We recommend our Supertech black nitrided intake valves and Inconel exhaust valves with all Supertech valve spring kits. Likewise, we offer the full range of Supertech: Valve keepers, mechanical tappets (rigid tappets) with matching shims and forged pistons. Make: BMW Fits: BMW S42 / M42 Supertech/s valve springs are made of an extreme pure chrome-silicon-vanadium-steel alloy to assure a very good durability for performance motors with high revolutions. They are developed with the use of computer simulations to prevent material fatigue under extreme conditions. The holder are made of a certified titanium alloy and CNC milled for the perfect fit to provide a long durability.