Rywire

About Rywire Motorsport Electronics

When a serious engine swap build demands wiring that won't let it down, builders turn to Rywire Motorsport Electronics. Founded and built around a passion for clean, competition-ready Honda and Acura builds, Rywire has earned a reputation as one of the most trusted names in motorsport electronics — the brand that serious swap builders wish they'd discovered sooner.

At the heart of the Rywire lineup are their engine wiring harnesses, offered in both budget and full Mil-Spec configurations. The Mil-Spec harnesses use color-coded wire with Raychem heat shrink, while the budget versions use an all-black wire layout with expandable mesh loom — both sharing the same proven design philosophy. Every harness is 100% quality-tested pin-to-pin and resistance-checked to ensure there are no voltage fluctuations in demanding conditions. All connectors are crimped with pneumatic heads for an OEM-level crimp every time, and each connection point is tagged with a white identification label to simplify installation. Rywire's harnesses are made in the USA and span a wide range of Honda and Acura engine families, including B-Series, D-Series, H-Series, F-Series, and K-Series engines — as well as popular swap platforms like the Nissan RB, VQ, and SR.

A clean engine bay isn't just about the wiring, which is why Rywire also produces purpose-built custom radiators engineered to fit tucked, swapped, and modified chassis without compromise. These radiators are designed to complement Rywire's harness ecosystem, making them a natural pairing for builders who want every component working in harmony.

For ignition system upgrades, Rywire offers direct ignition coil harnesses including coil-on-plug adapter plates and charge harnesses for B-Series and other engine families. These components allow builders to modernize ignition setups cleanly without cobbling together aftermarket solutions.

Rywire's harness ecosystem extends further with oxygen sensor extensions that integrate directly with their engine harness connectors, providing clean, pre-wired O2 sensor circuits for swaps where routing differs from the factory configuration. Completing the electrical foundation, Rywire's fuse and relay centers — including their popular Mil-Spec Fuse/Relay Box Sub-Harness — give builders a plug-and-play power distribution solution. These relay boxes include five relays and fuses covering computer, fan, fuel, starter, and O2 sensor circuits, and are designed to work seamlessly alongside Rywire switch panels and engine harnesses.

Why Builders Choose Rywire

• Mil-Spec construction using Raychem heat shrink, color-coded wiring, and pneumatically crimped connectors
• 100% pin-to-pin and resistance testing on every harness before it ships
• Modular design — chassis-specific sub-harnesses mean you only need to swap the sub-harness if you change platforms, not the entire loom
• Made in the USA with all-new connectors and materials
• Broad compatibility across Honda B, D, H, F, and K-Series engines, plus popular JDM swap engines
• Plug-and-play ecosystem — harnesses, fuse/relay boxes, and switch panels are designed to work together seamlessly

Whether you're building a tucked street car, a gutted circuit racer, or a drag-prepped swap, Rywire provides the electrical backbone to do it right the first time.