TGK Motorsport High Pressure Fuel Pump Piston Upgrade Kit - Audi EA839 2.9T/3.0T

The factory high pressure fuel pump on the EA839 2.9T and 3.0T engines found in the 2018–2026 Audi S4, S5, RS4, RS5, and SQ5 B9 platform runs a piston that was engineered to meet OEM fuel delivery requirements — not the demands of a modified or high-performance build. Under elevated boost, aggressive cam profiles, or increased injector duty cycles, the stock piston displacement becomes the bottleneck in your entire fueling system. The result is lean conditions at high RPM, inconsistent fuel rail pressure, and audible ticking from the factory two-piece tappet assembly that worsens with heat cycles and wear. These aren't minor inconveniences — on a turbocharged direct-injection engine pushing serious power, inadequate fuel delivery is a reliability and tuning ceiling you will eventually hit. The TGK Motorsport High Pressure Fuel Pump Piston Upgrade Kit resolves all of this at the source. The piston bore is increased to 11.70mm, delivering meaningfully greater fuel volume per stroke to keep rail pressure stable under full load on your B9 S4, S5, RS4, RS5, or SQ5. Every kit ships with a brand-new seal and tappet kit, and TGK's custom one-piece tappet design mechanically eliminates the flex and slap inherent in the OEM two-piece unit — killing the click without a tune patch or band-aid. This is a purpose-built internal upgrade that gives your EA839 the fuel delivery foundation it needs to support real performance.