Building a Fuel System for a 500hp Honda

Joel Guerra
3 min readJan 7

This is the companion guide of this YouTube video. For full context watch the video.

The goal of the system is to fuel my built turbocharged B18C to the tune of 500 horsepower. By my estimation this fuel system could support a forced induction 4-cylinder engine up to 700hp. This build is for a race car intended for use on private courses. Modifying your fuel system can be dangerous if done improperly. Consult a qualified professional.

This is my parts list (I will be replacing the fuel cell with an FIA-approved bladder cell but the system will work the same):

Below is the hose diagram for routing fuel between the components. Note that all of the feed lines (from fuel cell to fuel rail) are -8AN PTFE and all of the return lines (from fuel rail to fuel cell) are -6AN PTFE.

The fuel cell has -8AN fittings but the surge tank has -6AN fittings so an adapters is used on the feed line from the 75 micron filter to the surge tank. You will need -8AN fittings for the fuel pumps and filters.

The fuel rail and pressure regulator have ORB ports so ORB to AN fittings will be needed.

The rubber vent hose is looped to prevent spilling (per SCCA recommendations) and vents outside of the car away from the exhaust or any hot components.

Below is the wiring diagram for the pumps. Each fuel pump has its own 30 amp relay. The diagram shows 5 pin relays but as you can see the 5th pin is not used, so 4 pin would work as well. I used 8 AWG wire from my fuse box to the relays where I split to 14 AWG for each pump. Each pump has a 14 AWG chassis ground. The 8 AWG is fused with a 50 amp fuse at the fuse box. Each relay has a 20 amp fuse. The “kill switch” on my dash is optional but allows me to turn off the pumps manually. If you choose not to install a kill switch you can chassis ground pin 85 of the relays. The relays are activated by the original fuel pump power source by tapping into the factory harness at the factory fuel pump location.

wiring diagram

If this was helpful please let me know on YouTube or Twitter. If something is unclear please ask!

Joel Guerra

Software Engineer / Racecar Driver