Fuel-It BMW N54 Port Fuel Injection (PI) Kit for E-Series 135i 335i 535i – Auxiliary Injectors, Fuel Rail & Manifold Spacer – E85 Flex-Fuel/Conversion Ready, Flow-Matched Bosch Injectors – JB4 Integration, Optional Ethanol Content Sensor

Fuel-It Auxiliary Port Fuel System for BMW N54 E-Series

Build reliable fuelling headroom on your twin-turbo N54 with this direct-port auxiliary fuel upgrade from Fuel-It. Perfect for higher boost road and track builds running pump petrol, blends, or full ethanol, this add-on rail and spacer plate introduces a second set of injectors to support power where the factory high-pressure pump starts to struggle. Clean, reversible installation. OEM-like fit. Proven on real cars.

At MJ Modifications we run Fuel-It hardware on our own N54 projects and our customers consistently report smoother high-load delivery, safer knock resistance on alcohol fuel, and repeatable performance. If you are searching for a BMW 135i 335i 535i flex-fuel upgrade, N54 auxiliary injectors, a manifold spacer rail kit, or an E-Series ethanol-ready fuelling solution, this is the setup you want.

Why add auxiliary port fuel to your N54

This system places six additional injectors between the cylinder head and intake manifold using a precision anodised spacer and matching fuel rail. It supplements the stock DI system, giving tuners the extra capacity required for high ethanol content, bigger boost targets, and aggressive calibrations. Control the extra injectors with your chosen tuning solution. No cutting or permanent mods needed on E-Series platforms.

Highlights and performance advantages

• Confident fuelling for high ethanol content including up to 100 percent E85, ideal for flex-fuel tunes
• Supports stock turbos and uprated turbocharger setups on BMW E-Series N54
• Bolt-on spacer plate and rail for a tidy, reversible install
• Flow-matched Bosch 52 lb injectors for consistent cylinder-to-cylinder delivery
• Optional ethanol content sensor and Bluetooth analyser for live blend monitoring
• Platinum package provides a 0 to 5 V output for JB4 integration
• Black anodised components with stainless hardware for durability

Package options

Basic Kit

Note: no fuel lines are included with the Basic Kit.

• Fuel-It black anodised intake manifold spacer
• Fuel-It black anodised auxiliary fuel rail
• Black anodised aluminium and stainless fixings
• Dual supply port provision for inlets in the stock location. Contact us for guidance
• Optional return port for use with an upgraded fuel pressure regulator
• Six of each:
  • Flow-matched Bosch 52 lb injectors
  • Extended-length steel studs and a spacer bolt
  • BMW OEM gaskets

Bronze Kit

• Everything in the Basic Kit
• Entry-level fuel line connection kit:
  • Two custom Fuel-It fittings to keep the stock connections at the HPFP and engine bay feed line
  • -6AN 3/8 inch upgraded fuel lines
  • High-flow Y-adapter
  • 90 degree elbow for the rail connection

Silver Kit

• Everything in the Basic Kit
• Entry-level fuel line connection kit
• Upgraded feed hose that fully replaces the factory fuel line

Gold Kit

• Everything in the Basic Kit
• Entry-level fuel line connection kit
• Upgraded feed hose that fully replaces the factory fuel line
• Integrated ethanol content sensor for blend monitoring. An analyser is required to view content

Platinum Kit

• Everything in the Basic Kit
• Entry-level fuel line connection kit
• Upgraded feed hose that fully replaces the factory fuel line
• Integrated ethanol content sensor
• Bluetooth ethanol analyser with JB4-friendly output
  • 0 to 5 V signal for JB4 integration
  • Bluetooth enabled. iPhone or Android app purchased separately

Vehicle compatibility

Designed for BMW E-Series models fitted with the N54 engine including 135i, 335i, and 535i. Ideal for those researching BMW N54 auxiliary injectors, direct-port fuelling add-on, E85 conversion hardware, flex-fuel setup, and additional fuel rail solutions.

Installation and fitting

Professional installation is recommended. For supply, fitting, and setup in the UK, book with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

Fitment verification

We confirm compatibility before dispatch. Provide your UK registration or the last 7 digits of your VIN at checkout so we can ensure this N54 auxiliary fuel rail kit is correct for your car.

Part number

E-N54-PI-BA-BA-BA-550

Brand

Fuel-It

Warranty

One year Fuel-It warranty.

Lead time and important notes

• Built to order. Please allow 2 business days for shipping
• For off-road use only
• Ethanol sensors infer content based on the absence of petrol. Contaminated fuel can produce artificially high readings

Get the most from your N54 build

Choose this Fuel-It auxiliary port fuel system to unlock dependable capacity, accurate ethanol blend data, and an OEM-plus install on your E-Series BMW. Perfect for flex-fuel calibrations, uprated turbo cars, and anyone chasing strong top-end fuelling under sustained load.

Common searches: BMW 335i E85 conversion kit, N54 auxiliary injectors, 135i flex-fuel upgrade, 535i additional fuel rail, N54 manifold spacer plate, direct port fuelling kit, ethanol content sensor bundle, JB4 ethanol integration, BMW E-Series fuelling upgrade.