Spool Performance BMW B58 Gen1 Auxiliary Split Fuel System

Spool Performance BMW B58 Gen 1 Auxiliary Split Fuel System

The Spool Performance BMW B58 Gen 1 Auxiliary Fuel System is engineered for enthusiasts pushing beyond the limits of the factory fueling system. Designed around proper fuel architecture, this system separates direct injection (DI) and port injection (PI) supply to deliver stable, predictable fueling at higher power levels while maintaining a clean, OEM-style installation.

Every component is built for real-world usability, long-term reliability, and consistent performance as your build evolves.

Why a Split DI + PI Fuel System Matters

As power increases on the B58 platform, sharing a single fuel feed between DI and PI introduces instability:

• DI pulse cycles can create pressure fluctuations that affect PI injectors
• PI systems require boost-referenced fuel pressure for consistency
• Higher boost levels make fueling less predictable

By separating the fuel supply:

• DI and PI systems operate independently
• Fuel pressure remains stable under load
• Fuel delivery becomes consistent and repeatable at higher power levels

Key Features

• True split DI and PI fuel system architecture
• Retains OEM fuel pump top hat using precision aluminum fittings
• Plug-and-play wiring harness compatible with Reflex controller
• Dual Walbro 450 fuel pumps included
• Optional Walbro 525 fuel pump upgrade available
• Choice of standard relay or solid-state relay (PWM control)
• Compact, boost-referenced fuel pressure regulator
• Triple-layer PTFE fuel lines for durability and ethanol compatibility

Clean OEM-Style Installation

• No repinning or modification of factory wiring required
• Direct integration with OEM fuel pump top hat
• Optional billet top hats available separately
• Designed for clean, factory-like fit and finish

High-Quality Fuel System Components

• PTFE inner core for full fuel and ethanol compatibility
• Stainless steel reinforcement for high-pressure strength
• Nylon outer layer for abrasion resistance
• Built for high-heat, high-vibration environments and aggressive fuel blends

Scalable Performance

• Dual Walbro 450 pumps support high horsepower builds
• Optional Walbro 525 pumps for more demanding setups
• Flexible control options for precise fuel delivery
• Designed to grow with your build

Performance Benefits

• Stable and consistent fueling at high boost
• Improved reliability for high-performance applications
• Better fuel pressure control under load
• Supports large turbo and port injection setups
• Maintains drivability while increasing fuel capacity

FITMENT

BMW M240i / M240i xDrive (F22 / F23) – 2016–2018
BMW 340i / 340i xDrive (F30 / F31 / F34) – 2016–2018
BMW 440i / 440i xDrive (F32 / F33 / F36) – 2016–2018

Additional Notes:

• Designed specifically for B58 Gen 1 (B58B30) engines
• Not compatible with B58 Gen 2 / B58TU platforms unless otherwise specified
• Professional installation recommended
• Compatible with Reflex controller systems
• Ideal for high-performance street and track builds

Upgrade your BMW B58 Gen 1 with the Spool Performance Auxiliary Split Fuel System for maximum fueling control, scalability, and reliability as your build reaches higher performance levels.

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.