Radium Engineering Fuel Rail for 90-97 Accord/92-01 Prelude

Radium Engineering Fuel Rail - 1990-2001 Honda Accord/Prelude (F/H Series)

You swapped an H22 into your Accord or you're building a turbo F22 and the stock fuel rail can't keep up. You're running E85 and you need 35% more fuel volume than pump gas or you're pushing 300 whp and the stock rail's choking flow. The stock fuel rail's got a tiny bore and when you're trying to flow enough fuel for serious power, the pressure drops from the inlet end to the far end. Your first injector's seeing full pressure and your last injector's seeing 5 PSI less. Now you're tuning for the leanest cylinder and dumping extra fuel into the other three just to keep things safe. That's a bandaid, not a fix. Radium's fuel rail's got a way bigger internal bore than stock. We're not talking about a slightly larger bore. We're talking about enough bore to flow fuel for E85, for a turbo setup making 400 whp, or for whatever you're building without the rail becoming the restriction. The rail's CNC machined from 6061 billet aluminum, anodized, and laser-etched. The injector bores are 11mm ID just like stock so your factory injectors drop right in. The rail's got four 8AN ORB ports so you can set up your fuel system however you want. Inlet here, return there, regulator on the rail, fuel pulse damper, fuel pressure gauge, whatever. This does NOT come with fittings. You're buying those separately based on how you're setting up your fuel system.

Here's What Happens When Your Fuel Rail's Too Small

Your stock Accord or Prelude fuel rail works fine when the engine's stock. It doesn't work fine when you're asking it to flow 50% more fuel. Here's what actually happens. The fuel enters the rail at one end. As it flows through the small bore to feed each injector, it loses pressure from friction. By the time it gets to the last injector, the pressure's lower than it was at the first injector. On a stock setup that pressure drop might be 1-2 PSI. Nobody cares. On a high-flow setup with E85 or a turbo, that pressure drop's 5-8 PSI. Now cylinder one's rich and cylinder four's lean. You can't tune it out because the fuel pressure distribution's uneven. You end up running the whole engine richer than it needs to be just to keep cylinder four from going lean and detonating. You're leaving power on the table and you're burning extra fuel because your fuel rail's too restrictive. Radium's rail fixes that. The larger bore means the pressure drop from end to end is minimal. All four injectors see the same pressure. You can tune each cylinder properly instead of bandaiding the whole map to protect one lean cylinder.

Four 8AN ORB Ports - Set It Up However You Want

The rail's got four ports and they're all tapped 8AN ORB. That's way more flexibility than the stock rail gives you. Here's how most people set it up. One port's your inlet from the fuel pump. One port's your return to the tank if you're running a return-style system. One port's for a direct-mount fuel pressure regulator if you're mounting it on the rail. One port's for a fuel pulse damper or a fuel pressure gauge or you plug it if you don't need it. You can also set it up completely different. If you're running a returnless system with the regulator at the tank, you only need one inlet port and you plug the other three or use them for a damper and a gauge. If you're running a custom setup with dual feed or something weird, you've got four ports to work with. The 8AN ORB threads mean you're using O-ring boss fittings. Those seal with an O-ring in a groove instead of tapered pipe threads. They seal better and they don't leak. Radium sells 8AN ORB adapters to convert to 8AN hose ends if you're running braided line. They also sell direct-mount regulators and fuel pulse dampers that thread straight into the ports.

You're Buying Fittings Separately - Here's What You Need

This rail doesn't come with fittings. You're buying those separately because everyone's fuel system is different. Here's what you actually need. If you're running a return-style fuel system with a regulator on the rail, you need one 8AN ORB inlet fitting, one 8AN ORB return fitting, one 8AN ORB direct-mount regulator, and one 8AN ORB plug for the fourth port. You'll also need 8AN braided fuel line and 8AN hose ends to connect everything. If you're running a returnless system with the regulator at the tank, you need one 8AN ORB inlet fitting and three 8AN ORB plugs. Add a fuel pressure gauge or a fuel pulse damper if you want them. The fittings aren't included because there's no universal setup. A guy running a stock fuel system on E85 needs different fittings than a guy running a turbo setup with an aftermarket regulator and a fuel cell. Figure out how you're setting up your fuel system, then buy the fittings you need. Make sure you've got clearance for whatever you're bolting to the rail. A direct-mount regulator's big. A fuel pulse damper's big. They stick out and they might hit your intake manifold or your throttle body. Check Radium's dimensional drawings before you order.

Stock Injectors or OEM-Equivalent Only

This is an upgrade rail. It's not a top-feed conversion. That means you're using stock injectors or aftermarket injectors that are physically identical to stock. The injector bores are 11mm ID. That's the same as the factory rail. Your stock Honda injectors fit. Aftermarket injectors designed as drop-in OEM replacements fit. The injectors need to be the same height as stock and the O-rings need to be the same size and style as stock. If you want to run completely different injectors like a side-feed to top-feed conversion, this rail won't work. Talk to your tuner about what injector flow rate you need. Then talk to the injector company and make sure the injectors they're selling you are the right physical size to fit this rail. Most people either keep their stock injectors or upgrade to something from Injector Dynamics, Bosch, or Deatschwerks that's designed as an OEM replacement. Don't just buy injectors based on flow rate. Buy injectors that flow what you need AND fit the rail.

Fits F-Series and H-Series Engines in Accords and Preludes

This rail fits 1990-2001 Accords and 1992-2001 Preludes with F-series or H-series engines. If you've got an F20A, F20B, F22A1, F22A4, or F22A6 in your Accord, it fits. If you've got an H22A1, H22A4, or H23A1 in your Prelude or your Accord (some JDM Accords had H-series), it fits. The CB-chassis Accords from 1990-1993, the CD-chassis Accords from 1994-1997, and the CF-chassis JDM Accords from 1998-2002 with F-series engines all use this rail. The BB-chassis Preludes from 1992-2001 with H-series engines all use this rail. Pull your stock fuel rail off, bolt this one on, connect your fittings, and you're done. It's a direct replacement. Same mounting points, same injector spacing, same everything except it flows way more fuel.

What You Get

• Radium Engineering billet aluminum fuel rail - part number 20-0870
• Large internal bore (way bigger than stock, flows enough for E85/turbo/high power)
• CNC machined from 6061 aluminum, anodized and laser-etched
• 11mm ID injector bores (same as OEM, works with stock or equivalent injectors)
• Four 8AN ORB ports (NO fittings included, buy separately)
• Flexible fuel system setup (inlet, return, regulator, damper, gauge - use what you need)
• E85 and alcohol fuel compatible
• Direct bolt-in for F-series and H-series engines
• Made in USA

Fits These Engines

• F20A, F20B
• F22A1, F22A4, F22A6
• H22A1, H22A4
• H23A1

Fits These Cars

• 1990-1993 Honda Accord (CB7/CB9)
• 1994-1997 Honda Accord (CD5/CD7)
• 1998-2002 Honda Accord (CF4 - JDM only)
• 1992-1996 Honda Prelude (BB1/BB2/BB4)
• 1997-2001 Honda Prelude (BB6/BB8)

Note: This rail does NOT come with fittings or fuel line. You're buying those separately. You need 8AN ORB fittings - how many and what style depends on your fuel system (return vs. returnless, regulator on rail vs. regulator at tank, accessories like damper or gauge). You also need 8AN braided line and 8AN hose ends. Figure out your fuel system setup first, then buy the fittings you need. This is an upgrade rail - NOT a top-feed conversion. You MUST use stock injectors or OEM-equivalent injectors that are the same height with the same O-ring sizes. Don't buy injectors based on flow rate alone - make sure they physically fit this rail. Talk to your tuner for flow rate, talk to the injector company for physical dimensions. Direct-mount accessories like regulators and dampers are big - make sure you've got clearance before you order. Check Radium's dimensional drawings. The four 8AN ORB ports let you set up your fuel system however you want - inlet, return, regulator, damper, gauge, plugs, whatever your setup needs. Works with E85 and all alcohol fuels. Direct bolt-in replacement for stock fuel rail on F-series and H-series engines.