Rywire Engine Wiring Harness

Rywire Engine Wiring Harnesses: Wire-Tuck Precision Meets Mil-Spec Quality

Rywire Motorsport Electronics has built a dedicated following among Honda and Acura enthusiasts by focusing on one thing above all else: clean, reliable, high-performance engine wiring harnesses. Whether you're dropping a K-Series into an EF hatchback or building a full-tilt B-Series drag car, Rywire's harness lineup is engineered to make your swap both cleaner and more dependable than a re-pinned OEM unit ever could be.

Two Distinct Harness Tiers: Budget and Mil-Spec

The core design philosophy is identical across both tiers — what changes is the materials. The Budget harness uses all-black wire with an expandable mesh loom, while the Mil-Spec harness uses color-coded wire with Raychem heat shrink. The Mil-Spec line uses Teflon-coated wire rated to a maximum of 200°C , making it the preferred choice for high-heat engine bay environments and dedicated race builds. Both tiers share Rywire's exacting build standards: all connectors and materials are new, and each connector is crimped with pneumatic heads to ensure an OEM-quality crimp every time, then tagged with a white identification label for easy installation.

Engine Series Coverage

Rywire's harness catalog spans B-Series, D-Series, K-Series, F-Series, H-Series, and more , covering the majority of popular Honda and Acura engine swap combinations. The K-Series harness, for example, is designed around the 2002–2004 RSX K20 engine harness but can be used on K20 and K24 engine swaps easily. The H/F-Series Mil-Spec harness takes cross-compatibility even further — it is cross-compatible with both H-Series (H22/H23) and F-Series (F20B/Accord) engine types.

Modular Sub-Harness Design

One of the most practical features of Rywire's engine harness architecture is its modular split-harness design. Because the back-side interior/shock tower connection separates from the main harness, the engine harness can be used on multiple chassis provided the engine itself uses the same components. Each harness comes with a custom back-side sub-harness proprietary to the chassis chosen at order time — so if you ever change chassis, you only need a new sub-harness, not a whole new wire loom.

ECU and Aftermarket Electronics Compatibility

Rywire's engine harnesses aren't just for stock ECU swaps. They have experience building harnesses around MoTeC, Haltech, Syvecs, and AEM electronics , and dedicated harness lines exist for ECU platforms like Link, AEM Infinity, Emtron, FuelTech, and Haltech. The Link B-Series harness, for instance, features CAM/CRANK trigger capability, drive-by-wire throttle support, CAN BUS connectivity for loggers, dashes, and gauges, and is designed to accept T1 Race Development cam trigger hardware.

Quality Assurance and Custom Work

Every Rywire engine harness is 100% quality tested pin to pin and resistance checked to ensure no voltage fluctuations. For builders who need something truly bespoke, Rywire is capable of making custom harnesses for nearly any application , including fully Mil-Spec builds using Deutsch Autosport connectors and Raychem junction boots. All harnesses are proudly made in the USA and warranted to work correctly.