Spool Performance Fuel & Injector Upgrades – Audi RS Models (HPFP, E85 Kit & DI Injectors)
26th Dec 2025
Spool Performance Audi C8 RS6 Avant FX-350 Upgraded High Pressure Fuel Pump System - SP-EA825RS6-FX350
Order link:
The Spool Performance FX-350 Upgraded High-Pressure Fuel Pump System is a complete, high-output fueling solution engineered specifically for the Audi RS6 Avant (C8) equipped with the EA825 engine. Designed for high-horsepower and high-ethanol applications, this system removes the factory high-pressure fuel pump limitation that commonly restricts tuned and modified RS6 platforms.
At the core of this system are two Spool Performance FX-350 mechanical high-pressure fuel pumps, each featuring a larger internal bore than the factory units. This design delivers approximately 90% more fuel flow than stock, allowing the engine to safely support higher power levels, increased boost pressure, larger turbochargers, and elevated ethanol blends up to full E85.
The FX-350 operates at fuel pressures of up to 350 bar, significantly increasing injector efficiency while reducing injection time. Higher pressure combined with increased flow improves fuel atomization and combustion stability, especially under demanding performance conditions. Compared to lower-output pump solutions, the FX-350’s increased operating pressure directly translates into greater usable fuel delivery where it matters most.
This system is fully plug-and-play, requiring no cutting, splicing, or irreversible vehicle modifications. All components are engineered for direct fitment and long-term reliability. The FX-350 pumps are fully E85 compatible and built to withstand the demands of aggressive performance tuning.
To ensure fuel system protection and consistency, the kit includes a Bosch-spec 10-micron high-flow fuel filter, designed to protect both the high-pressure fuel pumps and injectors without introducing pressure drop on the low-pressure side. Optional integration of the Spool Performance Ethanol Content Monitor allows real-time ethanol percentage and fuel temperature monitoring through a mobile application, ensuring accurate tuning and fuel quality awareness.
The Spool Performance FX-350 system is intended for serious enthusiasts and high-performance builds. Custom ECU calibration is required to safely operate this system. Proper low-pressure fuel supply is also critical to prevent damage and ensure long-term reliability of the high-pressure fuel pumps.
Fitment
Vehicle Compatibility:
-
Audi RS6 Avant (C8)
Model Years:
-
2020–2024
Engine:
-
EA825 4.0T Twin-Turbo V8
Drivetrain:
-
Quattro AWD
Notes:
- Designed exclusively for Audi RS6 Avant C8 with EA825 engine
- Not compatible with other Audi or Volkswagen platforms
- Custom ECU tuning is required
- Adequate low-pressure fuel system support is mandatory
What’s Included
- 2 x Spool Performance FX-350 upgraded high-pressure fuel pumps
- 1 x Bosch-spec 10-micron high-flow fuel filter
- Upgraded fuel lines
- Required installation hardware
- Optional Spool Performance Ethanol Content Monitor kit with mobile app support
Why Upgrade the High-Pressure Fuel Pump
The factory high-pressure fuel pump on the Audi RS6 Avant becomes a limiting factor once power levels, boost pressure, or ethanol content are increased. The Spool Performance FX-350 eliminates this bottleneck by delivering substantially higher fuel volume and pressure, enabling safer and more consistent fueling under extreme load.
This upgrade is essential for:
- High-horsepower builds
- Larger turbocharger setups
- High ethanol or full E85 applications
- Reduced injector duty cycle at elevated power levels
Tuning and Fuel System Requirements
- ECU calibration changes are required before operation
- Improper tuning can result in engine or fuel system damage
- Low-pressure fuel supply must be sufficient to prevent cavitation or pump failure
- Failure to support the low-pressure side can void warranties and damage components
Note: 'New' merchandise may be returned for exchange or refund within 15 days from the date of shipment. 'New' merchandise must be unused and free from installation or mounting damage. Installation or modification of parts waives your right to returns, refunds, or exchanges.
Spool Performance Audi C8 RS7 Sportback FX-350 Upgraded High Pressure Fuel Pump System - SP-EA825RS7-FX350
Order link:
The Spool Performance FX-350 Upgraded High-Pressure Fuel Pump System is a high-capacity fueling upgrade engineered specifically for the Audi RS7 Sportback (C8) equipped with the EA825 engine. This system is designed to eliminate the factory high-pressure fuel pump limitation that restricts power output on tuned and ethanol-fueled RS7 platforms.
At the heart of the system are two Spool Performance FX-350 mechanical high-pressure fuel pumps, each featuring an increased internal bore compared to the factory pumps. This design delivers approximately 90% more fuel flow than stock, enabling the engine to safely support higher boost levels, larger turbochargers, and increased ethanol content up to full E85.
The FX-350 operates at fuel pressures of up to 350 bar, significantly improving injector efficiency while reducing injection duration. Higher operating pressure enhances fuel atomization and combustion stability, particularly under high-load and high-RPM conditions. Compared to lower-output pump solutions, the FX-350 provides a substantial increase in usable fuel delivery for demanding performance applications.
This Spool Performance system is fully plug-and-play, requiring no cutting, splicing, or permanent modification to the vehicle. All components are engineered for direct installation and long-term reliability. The FX-350 pumps are fully E85 compatible and built to withstand the demands of aggressive tuning and high-horsepower builds.
The kit includes a Bosch-spec 10-micron high-flow fuel filter, designed to protect the high-pressure fuel pumps and injectors from contaminants without introducing pressure drop in the low-pressure fuel system. An optional Spool Performance Ethanol Content Monitor is available, allowing real-time ethanol percentage and fuel temperature monitoring through a mobile application to support accurate tuning and fuel quality verification.
The Spool Performance FX-350 system is intended for serious performance enthusiasts. Custom ECU calibration is mandatory, and proper low-pressure fuel system support is required to ensure reliability and prevent component damage.
Fitment
Vehicle Compatibility:
-
Audi RS7 Sportback (C8)
Model Years:
-
2020–2024
Engine:
-
EA825 4.0T Twin-Turbo V8
Drivetrain:
-
Quattro AWD
Notes:
- Designed exclusively for Audi RS7 Sportback C8 with EA825 engine
- Not compatible with other Audi or Volkswagen platforms
- ECU tuning is required prior to operation
- Adequate low-pressure fuel system support is mandatory
What’s Included
- 2 x Spool Performance FX-350 upgraded high-pressure fuel pumps
- 1 x Bosch-spec 10-micron high-flow fuel filter
- Upgraded fuel lines
- Required installation hardware
- Optional Spool Performance Ethanol Content Monitor kit with mobile app support
Why Upgrade the High-Pressure Fuel Pump
The factory high-pressure fuel pump on the Audi RS7 becomes a restriction once power output, boost pressure, or ethanol content is increased. The Spool Performance FX-350 removes this limitation by delivering significantly higher fuel volume and pressure, allowing safer and more consistent fueling under extreme performance conditions.
This upgrade is essential for:
- High-horsepower builds
- Larger turbocharger setups
- High ethanol or full E85 fueling
- Reduced injector duty cycle at elevated power levels
Tuning and Fuel System Requirements
- ECU calibration changes are required before operation
- Improper tuning can cause severe engine or fuel system damage
- Low-pressure fuel supply must meet increased demand
- Insufficient low-pressure fueling can damage the high-pressure pumps and void warranties
Note: 'New' merchandise may be returned for exchange or refund within 15 days from the date of shipment. 'New' merchandise must be unused and free from installation or mounting damage. Installation or modification of parts waives your right to returns, refunds, or exchanges.
Spool Performance Audi RSQ8 FX-350 Upgraded High Pressure Fuel Pump System - SP-EA825RSQ8-FX350
Order link:
The Spool Performance FX-350 Upgraded High-Pressure Fuel Pump System is a high-output fueling solution developed specifically for the Audi RS Q8 equipped with the EA825 engine. This system addresses the factory high-pressure fuel pump limitation that becomes evident when increasing power, boost, or ethanol content on performance-oriented RS Q8 builds.
The system features two Spool Performance FX-350 mechanical high-pressure fuel pumps, each engineered with a significantly larger internal bore than the OEM pumps. This design delivers approximately 90% more fuel flow compared to stock, allowing the engine to safely support higher horsepower levels, increased boost pressure, larger turbocharger configurations, and high ethanol blends up to full E85.
The FX-350 is capable of operating at fuel pressures of up to 350 bar, which improves injector efficiency while reducing injection duration. Higher operating pressure enhances fuel atomization and combustion stability, especially under sustained high-load conditions. Compared to lower-output fuel pump upgrades, the FX-350 provides a substantial increase in usable fuel delivery for demanding performance applications.
This Spool Performance system is fully plug-and-play, requiring no cutting, splicing, or permanent vehicle modifications. All components are designed for direct installation and long-term reliability. The FX-350 pumps are fully E85 compatible and built to withstand aggressive tuning and high-performance driving conditions.
Included in the system is a Bosch-spec 10-micron high-flow fuel filter, engineered to protect both the high-pressure fuel pumps and fuel injectors from contaminants without introducing pressure drop on the low-pressure side of the fuel system. An optional Spool Performance Ethanol Content Monitor is available, providing real-time ethanol percentage and fuel temperature data through a mobile application to support accurate tuning and fuel quality monitoring.
The Spool Performance FX-350 system is intended for serious performance applications. Custom ECU calibration is mandatory, and sufficient low-pressure fuel system capacity is required to ensure proper operation and prevent component damage.
Fitment
Vehicle Compatibility:
-
Audi RS Q8
Model Years:
-
2020–2024
Engine:
-
EA825 4.0T Twin-Turbo V8
Drivetrain:
-
Quattro AWD
Notes:
- Designed exclusively for Audi RS Q8 with EA825 engine
- Not compatible with non-RS Q8 models or other Audi platforms
- ECU tuning is required prior to operation
- Proper low-pressure fuel system support is mandatory
What’s Included
- 2 x Spool Performance FX-350 upgraded high-pressure fuel pumps
- 1 x Bosch-spec 10-micron high-flow fuel filter
- Upgraded fuel lines
- Required installation hardware
- Optional Spool Performance Ethanol Content Monitor kit with mobile app support
Why Upgrade the High-Pressure Fuel Pump
The factory high-pressure fuel pump on the Audi RS Q8 becomes a performance bottleneck when power output, boost pressure, or ethanol concentration is increased. The Spool Performance FX-350 eliminates this restriction by delivering significantly higher fuel volume and pressure, ensuring consistent fueling under extreme performance demands.
This upgrade is ideal for:
- High-horsepower RS Q8 builds
- Larger turbocharger configurations
- High ethanol or full E85 fueling
- Reduced injector duty cycle at elevated power levels
Tuning and Fuel System Requirements
- ECU calibration changes are required before operation
- Improper tuning can result in engine or fuel system damage
- Low-pressure fuel supply must meet increased fuel demand
- Inadequate low-pressure fueling can damage the high-pressure pumps and void warranties
Note: 'New' merchandise may be returned for exchange or refund within 15 days from the date of shipment. 'New' merchandise must be unused and free from installation or mounting damage. Installation or modification of parts waives your right to returns, refunds, or exchanges.
Spool Performance Audi C8 RS6 Avant EA825 E85 Ethanol Analyzer Kit - SP-EA825-ETHANOL-KIT
Order link:
The Spool Performance E85 Ethanol Analyzer Kit is a precision fueling upgrade engineered specifically for the Audi RS6 Avant (C8) equipped with the EA825 engine. Designed for performance enthusiasts, this kit provides instant and accurate ethanol content readings, allowing drivers to safely monitor fuel blends from pump gas to full E85 without guesswork.
The kit features high-quality, ethanol-safe components engineered for reliable and repeatable measurements. Its plug-and-play design ensures clean installation with minimal effort, maintaining the factory appearance and functionality. Compatible with flex-fuel tuning setups, the Spool Performance Ethanol Analyzer Kit integrates seamlessly with ECU strategies, digital dashboards, and data logging systems.
This system empowers drivers to maximize performance while maintaining engine safety under varying ethanol concentrations. Knowing the exact ethanol content helps prevent detonation, ensures correct fueling, and allows drivers to safely exploit the advantages of high-ethanol fuels.
Fitment
Vehicle Compatibility:
-
Audi RS6 Avant (C8)
Model Years:
-
2020–2024
Engine:
-
EA825 4.0T Twin-Turbo V8
Notes:
- Designed specifically for Audi RS6 Avant C8 EA825 engine
- Not compatible with other Audi or Volkswagen models
- Fully compatible with E85 or flex-fuel tuning setups
- Plug-and-play installation with minimal modifications
Key Features
- Instant ethanol content readings for accurate fueling
- Designed exclusively for Audi RS6 Avant C8 for a clean fit
- Durable, high-quality, ethanol-safe components
- Plug-and-play wiring harness and tidy routing for easy installation
- Compatible with flex-fuel tunes and digital display integration
- Provides confidence and safety for high-power E85 applications
What’s Included
- 1 x Spool Performance Ethanol Analyzer module
- Plug-and-play wiring harness
- Installation hardware and instructions
Why Upgrade
Monitoring ethanol content is critical for safe, high-performance tuning, especially when running E85 or mixed fuels. The Spool Performance Ethanol Analyzer Kit removes uncertainty, providing real-time, accurate data so your RS6 Avant operates safely and efficiently under all fueling conditions. This upgrade is essential for anyone running flex-fuel tunes or maximizing performance on ethanol blends.
Note: 'New' merchandise may be returned for exchange or refund within 15 days from the date of shipment. 'New' merchandise must be unused and free from installation or mounting damage. Installation or modification of parts waives your right to returns, refunds, or exchanges.
The standard shipping rate applies to orders within the continental United States. If you intend to place an order outside of the continental US, please reach out to support@x-ph.com for assistance.
Spool Performance IFX-EA150 Upgraded DI Injectors for EA839 - SP-IFX150-EA839
Order link:
https://x-ph.com/spool-performance-ifx-ea150-upgraded-di-injectors-for-ea839-sp-ifx150-ea839/
The Spool Performance IFX-EA150 Upgraded Direct Injectors are engineered to unlock the full fueling potential of vehicles equipped with the EA839 engine platform. Designed for high-boost, high-airflow builds, these injectors deliver 35% more flow and an additional 1,000 psi of maximum rail pressure capability, providing the fueling headroom necessary for aggressive tuning, ethanol blends, and big-turbo applications.
Factory EA839 injectors can become a limiting factor when increasing boost, airflow, or ethanol content. Issues such as high-RPM pulse-width extensions, late injection events, and cylinder-to-cylinder imbalance may occur when the direct injection system is pushed beyond its stock design. The IFX-EA150 injectors eliminate these constraints by delivering increased flow, higher pressure, and optimized spray patterns, ensuring consistent fueling under extreme conditions.
Key advantages include:
- 35% Increased Flow Capacity – Delivers more fuel per injection event with reduced pulse width at high RPM.
- +1,000 psi Additional Pressure Capability – Enhances atomization and combustion consistency under high cylinder pressures.
- Shorter Injection Window – Achieves fueling targets earlier in the cycle for cleaner, more complete combustion.
The IFX-EA150 supports higher boost levels, more aggressive ignition timing, and stable fueling at high RPMs where stock injectors fall short. They enable safe use of ethanol blends, including E50–E85, without exceeding the limits of the DI system. These injectors are ideal for big turbo, hybrid turbo, and high-ethanol EA839 builds, providing consistent lambda, safe injector pulse widths at redline, and stable spray patterns even with ethanol’s higher volumetric demand.
When paired with a Spool Performance FX-350 high-pressure fuel pump, the IFX-EA150 injectors provide full E85 fueling capability for high-power EA839 platforms.
Spool Performance provides full tuner support and calibration guidance, ensuring your injectors integrate seamlessly with your ECU and performance setup.
Fitment
Audi
- S4 (B9)
- S5 (B9)
- A6/S6 (C8)
- A7/S7 (C8)
- A8
- Q7
- Q8
- SQ5
Porsche
- Cayenne (2019+)
- Panamera (2019+)
- Macan S/GTS/Turbo (2019+)
Volkswagen
-
Touareg
Engine:
-
EA839 3.0T Twin-Turbo V6 / applicable DI configurations
Notes:
- Designed specifically for high-performance EA839 applications
- Optimized for E85 and high-ethanol blends
- Works best when paired with FX-350 HPFP for full E85 support
- Requires proper tuning for safe operation
Key Features
- 35% more flow than OEM injectors
- +1,000 psi increased pressure capability
- Shorter injection window for cleaner combustion
- Optimized for E50–E85 ethanol blends
- Stable fueling at high RPM and high boost
- Ideal for big turbo and hybrid turbo EA839 builds
- Tuner-friendly with calibration support from Spool Performance
What’s Included
- 4 x Spool Performance IFX-EA150 Direct Injectors
- Installation instructions and calibration guidance
Why Upgrade
Factory EA839 injectors can limit high-performance builds, especially when using ethanol blends or large turbos. The Spool Performance IFX-EA150 injectors provide higher flow, increased pressure, and optimized atomization, allowing your EA839 engine to reach its full potential safely and reliably. Perfect for enthusiasts seeking maximum power with E85 compatibility and consistent fueling across all cylinders.
Note: 'New' merchandise may be returned for exchange or refund within 15 days from the date of shipment. 'New' merchandise must be unused and free from installation or mounting damage. Installation or modification of parts waives your right to returns, refunds, or exchanges.
The standard shipping rate applies to orders within the continental United States. If you intend to place an order outside of the continental US, please reach out to support@x-ph.com for assistance.
Spool Performance IFX-EA150 Upgraded DI Injectors for EA825 - SP-IFX150-EA825
Order link:
https://x-ph.com/spool-performance-ifx-ea150-upgraded-di-injectors-for-ea825-sp-ifx150-ea825/
The Spool Performance IFX-EA150 Upgraded Direct Injectors are engineered to unlock the full fueling potential of vehicles equipped with the EA825 engine platform. Designed for high-boost, high-airflow builds, these injectors deliver 35% more flow and an additional 1,000 psi of maximum rail pressure capability, providing the fueling headroom required for aggressive tuning, ethanol blends, and big-turbo applications.
Factory EA825 injectors can quickly become a limiting factor when boost, airflow, or ethanol content is increased. Symptoms such as high-RPM pulse-width extensions, late injection events, and cylinder-to-cylinder fueling imbalance may appear when the direct injection system is pushed beyond its stock design. The IFX-EA150 injectors eliminate these constraints by providing increased flow, higher pressure, and optimized spray patterns, ensuring reliable fueling under extreme conditions.
Key performance advantages include:
-
35% Increased Flow Capacity – Delivers more fuel per injection event with reduced pulse width at high RPM.
-
+1,000 psi Additional Pressure Capability – Stronger atomization and improved combustion consistency even under extreme cylinder pressures.
-
Shorter Injection Window – Meets fueling targets earlier in the cycle for cleaner, more complete combustion.
The IFX-EA150 supports higher boost, more aggressive ignition timing, and stable fueling at high RPMs where stock injectors fall short. They enable safe operation on ethanol blends, including E50–E85, without exceeding the limits of the DI system. These injectors are ideal for big turbo and hybrid turbo EA825 builds targeting 800–1000+ whp, providing consistent lambda, safe injector pulse widths at redline, and stable spray patterns even with ethanol’s higher volumetric demand.
When paired with the Spool Performance FX-350 High-Pressure Fuel Pump, the IFX-EA150 injectors provide a complete DI-only fueling solution, supporting full E85 capability and simplifying high-power builds without requiring port injection. This pairing ensures OEM-like reliability with extreme fueling capacity and a clean, emissions-friendly configuration.
Spool Performance provides full tuner support and calibration guidance, ensuring seamless integration and optimal performance.
Fitment
Audi
- RS Q8
- S8
- RS6 Avant (C8)
- RS7 Sportback (C8)
- A8 (60 TFSI)
- SQ7
- SQ8
Porsche
- Panamera (V8 models)
- Cayenne (V8 models)
Lamborghini
-
Urus
Engine:
-
EA825 4.0T Twin-Turbo V8
Notes:
- Designed specifically for high-performance EA825 applications
- Optimized for E85 and high-ethanol blends
- Works best when paired with FX-350 HPFP for DI-only full E85 support
- Requires proper tuning for safe operation
Key Features
- 35% higher flow than OEM injectors
- +1,000 psi additional rail pressure capability
- Shorter injection duration for cleaner combustion
- Supports E50–E85 ethanol blends safely
- Maintains consistent lambda under high load
- Stable atomization and spray pattern at high RPM and ethanol volume
- Ideal for big turbo and hybrid turbo EA825 builds
- Compatible with Spool Performance FX-350 HPFP for complete DI-only fueling
- Tuner-friendly with calibration support from Spool Performance
What’s Included
- 4 x Spool Performance IFX-EA150 Direct Injectors
- Installation instructions and calibration guidance
Why Upgrade
Factory EA825 injectors are a bottleneck in high-power builds, especially on ethanol blends or large-turbo applications. The Spool Performance IFX-EA150 injectors provide higher flow, increased pressure, and optimized atomization, enabling your EA825 engine to reach its full potential safely and reliably. When combined with the FX-350 HPFP, this creates the strongest DI-only fueling strategy available, supporting extreme power levels without the complexity of supplemental fueling.
Note: 'New' merchandise may be returned for exchange or refund within 15 days from the date of shipment. 'New' merchandise must be unused and free from installation or mounting damage. Installation or modification of parts waives your right to returns, refunds, or exchanges.
The standard shipping rate applies to orders within the continental United States. If you intend to place an order outside of the continental US, please reach out to support@x-ph.com for assistance.