Spool FX-170 HPFP Upgrade | BMW N55
The Spool Performance FX-170 is a High-Pressure Fuel Pump (HPFP) upgrade for BMW N55 engines. This pump is specifically designed for single turbo -35i models where the stock fuel system quickly becomes a limitation in tuning.
What is the FX-170?
The FX-170 is an upgraded HPFP with a larger piston diameter than the stock pump. This allows for approximately +50% greater fuel flow.
- Approx. +50% flow compared to stock
- Full E85 compatibility
- Plug & Play installation without cutting or wiring changes
- Enables higher fuel delivery at increased power levels
Additional capacity allows for:
- Higher ethanol blends
- Larger turbochargers
- Wider tuning possibilities
Why is an upgrade necessary?
The stock N55 HPFP is a significant limitation in tuning:
- Insufficient fuel delivery for higher power levels
- Limited use of ethanol blends
The FX-170:
- Significantly increases fuel system capacity
- Expands the platform's fuel limits
- Enables more powerful and safer tuning
Software Requirements
- Requires software modifications before use
- Calibration must be performed before using the pump
Spool:
- Provides necessary calibration data to the tuner
- Assists in finding an experienced tuner if needed
Note: Spool does not offer ready-made custom tunes
Important note: LPFP
The low-pressure fuel system is critical:
- Insufficient supply can damage the pump and injectors
- HPFP lubrication relies on fuel flow
- Lack of fuel can lead to wear and failure
Recommendation: ensure adequate low-pressure side upgrade