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.
Frequently Asked Questions
Will this HPFP piston upgrade work on both the 2.9T and 3.0T EA839 engines in the B9 Audi S4, S5, RS4, RS5, and SQ5?
Yes. The TGK Motorsport HPFP Piston Upgrade Kit is specifically engineered for the EA839 engine platform shared across the 2018–2026 Audi B9 S4, S5, RS4, RS5, and SQ5 in both 2.9T and 3.0T configurations. One kit covers all of these applications — no variant selection required.
What causes the clicking noise from the stock HPFP, and how does TGK's one-piece tappet fix it?
The factory tappet on the EA839 HPFP is a two-piece design that allows a small amount of mechanical play between its components. Under the rapid cycling of the pump, this play produces an audible tick that becomes more pronounced as the tappet wears or heat cycles accumulate. TGK's custom one-piece tappet eliminates that articulation point entirely — the solid construction has no internal joint to flex or slap, removing the mechanical source of the noise rather than masking it.
Do I need a tune after installing the upgraded HPFP piston?
Yes a tune is required to install or run the upgraded piston — the increased displacement is a hardware improvement that your existing fuel management system can accommodate. However, if you are installing this kit as part of a broader performance build on your B9 S4, S5, RS4, RS5, or SQ5, pairing it with a supporting ECU tune will allow your calibrator to take full advantage of the improved fuel delivery capacity, particularly at high RPM and elevated boost levels.
What is included in the TGK HPFP Piston Upgrade Kit?
The kit includes the 11.70mm upgraded piston, a complete brand-new seal kit, and TGK's custom one-piece tappet. Everything needed to fully rebuild and upgrade your high pressure fuel pump internals is included — you will not need to source additional seals or tappet components separately.
Is this a drop-in upgrade or does it require machining?
The TGK HPFP Piston Upgrade Kit is designed to install into your factory EA839 HPFP housing without requiring any machining. It is an internal rebuild and upgrade procedure. We recommend this installation be performed by a qualified technician familiar with direct-injection fuel system components, as proper torque specifications and cleanliness during assembly are critical to pump integrity and long-term reliability.