Product Description
The AEM 25-103BK B16 B-Series High Volume Fuel Rail is a black-anodized billet-aluminum fuel rail designed for compatible Honda B16A2 and B16A3 applications, including the 1999-2000 Civic Si and 1994-1997 Civic del Sol VTEC.
With a 1/2-inch internal fuel bore, support for factory-style or custom fuel plumbing, and an auxiliary 1/8 NPT port, the 25-103BK can be used in anything from a factory-style B16 fuel system to a larger return-style JBtuned B-Series fuel-system configuration.
Quick Specs
- Manufacturer: AEM Performance Electronics
- AEM Part Number: 25-103BK
- Engine Applications: Honda B16A2 / B16A3
- Fuel Rail Bore: 1/2 inch
- Material: CNC-machined billet aluminum
- Finish: Black anodized with AEM laser engraving
- Auxiliary Port: 1/8 NPT
- Fuel-Line Compatibility: Factory-style or custom AN fuel plumbing
- Fuel Injectors Included: No
- Installation Hardware / Fittings: Included by AEM
AEM 25-103BK B16 Fitment
AEM officially lists the 25-103BK for the following Honda applications:
- 1999-2000 Honda Civic Si – B16A2
- 1994-1995 Honda Civic del Sol VTEC – B16A3
- 1996-1997 Honda Civic del Sol VTEC – B16A2
The 25-103BK is also commonly considered when building a B16-powered Civic, Integra, or other Honda swap. Because swapped vehicles can use different intake manifolds, injectors, fuel-pressure regulators, and fuel-system layouts, verify the specific engine and intake-manifold combination before ordering.
1/2-Inch High-Volume Fuel Bore
AEM manufactures the 25-103BK with a 1/2-inch internal fuel bore. The larger rail volume helps support increased fuel-flow requirements and also helps dampen fuel-pressure pulsations created by larger injectors.
AEM rates the fuel rail itself for fuel-flow capability in applications up to 1,000 horsepower. This is a fuel-rail flow-capability specification and is not a horsepower rating for the complete vehicle or fuel system.
Actual fuel-system capability depends on the fuel pump, injectors, regulator, feed and return plumbing, filter, electrical supply, fuel type, engine combination, and tuning.
Factory Fuel Line or Custom AN Plumbing
The AEM 25-103BK can support both factory-style and custom fuel-system configurations.
AEM supplies a fuel-line fitting for use with the applicable factory fuel line. The rail is also pre-tapped for compatible -6AN / 9/16-18 fuel fittings when custom fuel plumbing is being used.
This makes the 25-103BK useful whether the goal is simply replacing or upgrading the original B16 fuel rail or incorporating the rail into a larger aftermarket fuel system.
Choose the Fuel Pressure Regulator That Matches Your System
The correct fuel-pressure-regulator arrangement depends on how the rest of the B16 fuel system is being configured.
Factory-Style / Rail-Mounted Regulator
The AEM rail retains the conventional Honda B-Series rail-mounted fuel-pressure-regulator layout, allowing compatible factory-style regulator arrangements to be used.
AEM Adjustable Rail-Mounted Regulator
For the B16A2 and B16A3 applications supported by this rail, the appropriate adjustable AEM rail-mounted regulator is the AEM 25-300BK Honda / Acura Adjustable Fuel Pressure Regulator.
The 25-300BK mounts directly to the compatible Honda or AEM fuel rail and provides an adjustable 1:1 vacuum / boost-referenced regulator while retaining the compact rail-mounted configuration.
External Regulator / Larger Return-Style System
For larger custom fuel systems, the rail can instead be incorporated into an external-regulator configuration using a regulator such as the AEM 25-302BK Universal Adjustable Fuel Pressure Regulator.
External-regulator systems should be configured as a complete feed-and-return system so the rail, regulator, fuel lines, filter, pump, and return plumbing work together as one fuel-delivery system.
1/8 NPT Auxiliary Port
The 25-103BK includes an additional 1/8 NPT port. AEM provides this port for uses such as a fuel-pressure gauge or a fuel supply for a wet nitrous system.
It can also provide a convenient location for compatible fuel-pressure instrumentation when the overall fuel-system layout supports the installation.
Keeping the OEM Honda Fuel Filter?
If the vehicle is retaining the factory firewall-mounted Honda fuel filter and only needs the engine-side feed connection upgraded, the JBtuned B-Series OEM Filter-to-Rail Fuel Line provides the Level 1 starting point for compatible B-Series fuel systems.
This configuration retains the OEM fuel filter and existing chassis plumbing while upgrading the fuel connection between the filter and the B-Series fuel rail.
Building a Tucked or Higher-Capacity B16 Fuel System?
For turbocharged, higher-output, or cleaner tucked B16 builds, the fuel rail is only one part of the complete fuel-delivery system.
The JBtuned B-Series Fuel Line Tuck Kit upgrades the engine-bay feed and return plumbing, replaces the large OEM firewall-mounted fuel filter with a compact inline filter, and retains the factory chassis fuel lines.
For builds that need the factory chassis fuel plumbing replaced from the tank to the engine and back, see the JBtuned B-Series Full Tucked Fuel System.
For a complete PTFE fuel system configured around ethanol-content-sensor integration, see the JBtuned B-Series Complete Flex-Fuel System.
What Is Included?
AEM supplies the 25-103BK with the hardware, fittings, and injector O-rings required for the supported AEM fuel-rail installation.
- AEM 25-103BK B16 high-volume fuel rail
- Applicable installation hardware
- Factory fuel-line fitting
- Injector O-rings
- 1/8 NPT auxiliary-port plug
Fuel injectors, fuel-pressure regulator, aftermarket AN fuel lines, fuel pump, and other fuel-system components are not included unless purchased separately.
Installation Notes
Fuel pressure must be safely relieved before removing or servicing the fuel rail. Inspect injector seals, O-rings, and other sealing components during installation and replace any damaged components as required.
After installation, pressurize the fuel system and carefully inspect the rail, injectors, regulator, fittings, and fuel-line connections for leaks before starting or operating the vehicle.
If you are using the 25-103BK in a B16 swap or custom fuel-system combination and are unsure which regulator or JBtuned fuel-system configuration is appropriate, contact JBtuned before ordering.
