Product Description
The AEM 25-104BK High Volume Fuel Rail is a black-anodized billet-aluminum fuel rail designed for compatible Honda F22A1, F22A4, F22A6, H22A1, H22A4, and H23A1 engines.
Common applications include Honda Accord and Prelude combinations using these F-Series and H-Series engines, as well as compatible H22 / H23 swap configurations.
With a 1/2-inch internal fuel bore, support for factory-style or custom fuel plumbing, and an auxiliary 1/8 NPT port, the 25-104BK can be used in anything from a relatively straightforward factory-style fuel system to a larger return-style performance fuel system.
Quick Specs
- Manufacturer: AEM Performance Electronics
- AEM Part Number: 25-104BK
- Engine Applications: F22A1, F22A4, F22A6, H22A1, H22A4, H23A1
- 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 25-104BK F22 / H22 / H23 Fitment
AEM currently lists the 25-104BK for the following Honda engines:
- F22A1
- F22A4
- F22A6
- H22A1
- H22A4
- H23A1
These engines are commonly found in Honda Accord and Prelude applications. The rail may also be used in compatible engine-swap combinations using the supported engine and intake-manifold configuration.
Because H22, H23, and F22 swaps can use different intake manifolds, injectors, regulators, and fuel-system layouts, verify the specific engine and intake-manifold combination when using the rail outside its original vehicle application.
1/2-Inch High-Volume Fuel Bore
AEM manufactures the 25-104BK with a 1/2-inch internal fuel bore. The larger rail volume supports increased fuel-flow requirements and helps dampen fuel-pressure pulsations created by larger injectors while remaining compatible with factory-size 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 25-104BK can be incorporated into either a factory-style fuel system or a custom aftermarket fuel system.
AEM supplies the appropriate fuel-line fitting for compatible factory fuel-line installations. The rail also provides threaded fuel connections for builders converting to custom -6AN / 9/16-18 plumbing.
This gives the 25-104BK flexibility for naturally aspirated street cars, turbocharged builds, engine swaps, and more complete aftermarket fuel-system configurations.
Choose the Correct Fuel Pressure Regulator
The correct AEM rail-mounted fuel-pressure regulator depends on which engine application is being used with the 25-104BK.
F22A1 / F22A4 / F22A6
For compatible F22A-series applications, the appropriate rail-mounted AEM regulator is the AEM 25-300BK Honda / Acura Adjustable Fuel Pressure Regulator.
H22A1 / H22A4 / H23A1
For compatible H22 and H23 applications using the AEM rail, the corresponding rail-mounted regulator is the AEM 25-303BK Honda / Acura Adjustable Fuel Pressure Regulator.
Both regulator versions provide an adjustable 1:1 vacuum / boost-referenced fuel-pressure-regulator solution while retaining the compact Honda rail-mounted regulator arrangement.
External Regulator / Larger Return-Style Fuel 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 25-104BK includes an additional 1/8 NPT port. AEM provides this port for applications such as a fuel-pressure gauge or an additional fuel supply for a wet nitrous system.
The port can also provide a convenient location for compatible fuel-pressure instrumentation when the overall fuel-system configuration supports the installation.
Building an H2B Civic or Integra?
The AEM 25-104BK is also a strong fit for H2B engine-swap applications using a compatible H22 / H23 fuel-rail configuration.
If this rail is being installed as part of an H2B swap in an EG / EK Civic or DC Integra, see the JBtuned H2B Fuel Line Tuck Kit.
The JBtuned H2B kit provides the engine-bay feed and return plumbing needed to integrate the H-Series engine into the Civic / Integra chassis fuel system and can be configured around compatible aftermarket fuel rails and regulator arrangements.
The H2B Fuel Line Tuck Kit is specifically for H2B-swapped Civic / Integra applications and is not intended as a fuel-line kit for a conventional Accord or Prelude installation.
What Is Included?
AEM supplies the 25-104BK with the hardware, fittings, and injector O-rings required for the supported fuel-rail installation.
- AEM 25-104BK 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, washers, and other sealing components during installation and replace 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 25-104BK in an H22, H23, F22, or H2B swap combination and are unsure which regulator or fuel-system configuration is appropriate, contact JBtuned before ordering.
