Description
Fits: 2007-2008 Audi RS4
Overview
The APR High Pressure Fuel Pump (HPFP) increases fuel delivery volume by 41% over stock, enabling the direct injection system to meet the demands of high horsepower setups. This is achieved through enhanced displacement and high-quality components crafted to exacting tolerances.
How the Direct Injection System Works
- Low Pressure Fuel Pump (LPFP): Delivers fuel from the tank to the HPFP at approximately 4 to 6 bar.
- High Pressure Fuel Pump (HPFP): Elevates fuel pressure to a maximum of 136 bar, supplying high-pressure fuel directly to the injectors.
The Problem
Fuel displacement from the HPFP is tied to its internal bore size and camshaft stroke. Upgraded supercharger and turbocharger systems can strain the system, particularly at mid to lower RPMs, leading to insufficient fuel volume.
The APR Solution
APR addresses this issue by significantly increasing the HPFP's displacement. This ensures a higher volume of fuel is available at all RPMs, maintaining stable fuel pressure during demanding conditions.
Key Features
- 41% Increased Fuel Volume: Ideal for high-output builds.
- High-Quality Components: Utilizes genuine Hitachi parts made in Germany for optimal reliability.
- Precision Engineering: Tolerances as tight as .00004" (dimensional) and .00005" (geometric).
- DLC Coated Piston: Provides exceptional surface hardness and reliability.
- Comprehensive Rebuild: Includes new factory pumps and all necessary internal seals replaced.
Technical Specifications
- Material: Heat-treated bearing-grade stainless steel.
- Spring Seals Replaced: Ensures long-term reliability and performance.
- Includes Factory Pivoting Head: Reduces cam follower wear and piston side loading.
Internal Testing
Each APR HPFP is assembled under strict guidelines and tested on APR's test rig to ensure proper operation. This process helps identify potential issues like installation errors or leaking seals, significantly reducing the risk of damage to the engine's camshaft.
Proven Track Record
APR has led the HPFP upgrade market since 2006, supplying components for various race applications and achieving numerous motorsport victories. With thousands of pumps sold, APR's expertise ensures a product that meets high-performance standards.
OEM Components
APR HPFPs are built using genuine Hitachi components, ensuring OEM-level reliability. All parts are manufactured in the USA using medical-grade precision machinery.
Emissions Compliance
This product complies with the EPA’s Tampering Policy and is legal for on-street use in all states except California. Testing for 50-state compliance is ongoing.
Features Summary
- 41% Increase in Fuel Volume
- Supports High-Power Applications
- Fully Rebuilt and Machine Tested
- DLC Coated Piston and Upgraded Spring
- Extremely Tight Tolerances for Performance
