Rywire Breaks Down Its Aftermarket Engine Harnesses & Wiring

Over the last decade, as Honda builders have become increasingly focused on ultra-clean, organized, and masterfully executed engine bays, the need for critical ancillary parts and services has skyrocketed. From high-level bodywork to custom metal fabrication and even dress-up hardware, having a well-executed bay is just one of the many items on an almost endless checklist. One of the most crucial items, whether the project involves a basic swap with bolt-ons or a fully built turbo terror, is wiring. Creativity combined with good old-fashioned trial and error has resulted in a number of clever workarounds that allow for the fusion of engines and chassis from various generations using only the factory-issued harnesses and a bit of finesse. In some cases, however, the age and condition of the harness can be limiting factors, especially when you consider that the most popular Honda platforms to build fall between the '90-'96 era. For those in the competitive race world, the factory harness simply isn't an option when dealing with high-dollar management systems.

A number of wiring specialists have surfaced over the years, with some catering specifically to the Honda market and others branching out to other makes and models to meet the demand of a booming industry that has more than enough demand to keep the suppliers busy. One of the most popular and highly respected is Garden Grove, California—based, Rywire Motorsport Electronics. Owner and Honda enthusiast Ryan Basseri has been tinkering with Honda wiring and all of its quirks and intricacies for more than 15 years. What started as a hobby soon led to a small upstart and eventually a successful business with a storefront, employees, and a customer base that doesn't seem to be tapering. So successful, in fact, that Basseri tells us his shop is currently assembling and shipping 50 to 70 complete harnesses on a weekly basis.

The Foundation

By far the most popular, Rywire's Honda B-series entry-level harnesses offer a few main benefits for the street, weekend track, or show car builder. A plug-and-play affair, these harnesses can be configured to bridge the gap between opposing OBD designations and offer a seamless solution for those using an engine from one generation, and perhaps an ECU and distributor from another. While some may opt to patch the factory harness on their own in an effort to save money, an aftermarket harness will completely replace old wiring and connectors that may be prone to rotting or shorting. The new unit presents a cleaner, one-piece design that snakes around the engine rather than sitting atop the shock towers, which in turn can de-clutter the bay significantly. Modular in design, these harnesses are expandable, allowing for the addition of future upgrades as the build progresses.

Highlights:

• Affordable
• Plug-and-play, one-piece design
• Less intrusive appearance for a cleaner bay
• New, reliable wiring and connectors to replace aging factory harness

Street, Show, and Weekend Warriors

For those starting with a standalone engine management system, harness options that include boost solenoids and various sensors are easily added to the recipe. Pre-planned sensor terminations offer an easy install for the end user, and because ECU selection is determined prior to the construction of the harness, the correct ECU connectors are utilized, keeping installation time short and painless. Similar to an entry-level harness in terms of expandability, future changes and upgrades are supported as well.

Highlights:

• Proper standalone ECU connectors
• No patch harness required
• Correct sensor terminations used for easy plug-in solution

The Big Guns

The number of full race applications being ordered through Rywire has grown substantially over the past few years. With many drag, drift, and time attack drivers relying on high-end engine management systems, the need for completely one-off, custom harnesses has never been greater. These harnesses incorporate built-in fuses, relays, or PDMs (power distribution module) that grant teams highly advanced data for analyzing during or after each race or test session. Basseri serves as a consultant of sorts, offering his experience and insider info to help clients select the best options for their particular setup. Once the parameters are set, Basseri and his team can complete a full race-spec, four-cylinder harness in about three to five days, depending on the options requested. Engines with more cylinders (6-12) require a few more days for completion. In order to ensure quality and consistency, every harness assembled is tested and resistance checked to verify there are no voltage fluctuations before being shipped to its new home.

Highlights:

• Compatible with even the most advanced management systems
• Limitless expansion options
• Built-in fuses, relays, or PDM
• Sealed connections
• Personal build consultation

Tools of the trade. Rywire owner Ryan Basseri and employee Ryan Der rely on these to get the job done, day in and day out. The current workflow includes up to 70 harnesses per week, not including the one-off race versions they build regularly as well.

Things start off as nothing more than a bunch of wires, sometimes color-coded, sometimes all black, depending on the type of harness purchased. (All-black wiring is more cost effective and indicates an entry-level version.)

Raychem DR25 heat-shrinkable wire covering along with wire labeling and Rywire tag logos are introduced and corresponding plugs are pinned.

While some customers use an OEM ECU, others might opt for a harness compatible with something like AEM’s Infinity or other stand-alone system.

Quick-disconnect fittings are often used by race teams for fast removal of engines, and in recent years, show car builds have incorporated them as the crowning touch to a high-level build.

The correct number of wires and proper lengths are chosen based on the customer’s order.

Rywire adds Kapton tape to all bulkhead-style harnesses (Mil-spec or Autosport). This tape helps keep wires secure and acts as a heat barrier when heat shrinking the protective boot—shown here moments before being heated and properly fitted.

Labor intensive, the process of concentric twisting is a strategy that involves twisting the wires around themselves in opposing direction, allowing the loom to remain as flexible as possible. This technique is time consuming but allows a harness to contour to any direction.

Entry-level Rywire ’88-’91 Civic/CRX harness compared to that of the factory unit.

Here is a completed harness with expandable loom ready to be installed.

Here you see a custom Rywire harness and MoTeC system intended for high-level competition with a sealed boot covering all connections. Twisted wire grants flexibility and heat-resistant loom keeps wires safe from outside elements. Below that is an AEM stand-alone system with an entry-level harness intended for a street, show, or weekend track car. Necessity and a substantial price tag difference separate the two types.

Though the Rywire crew can construct the majority of available harnesses from memory, Basseri and Der keep multiple reference guides on hand for consistency and strict quality control.

Beyond engine harnesses, Rywire Motorsport Electronics also offers a number of accessories. Brake kits, coil-on-plug conversion kits, sub harnesses, Mil-spec connectors and plates, and much more.