It is perhaps deliberate irony that Chase McMaster, head honcho at Honda engine swap accessories company Chase Bays, took a US-market 1990 Honda CR-X HF and transformed it into a JDM EF8 SiR-aping beast. While both may be Rexs, each was meant for distinctly different kinds of car consumers when they were first produced.

The HF was a champion of fuel economy, coming with a 1.5-liter eight-valve SOHC D-series mill capable of 62 horsepower, 90 pound-feet of torque, and reportedly hitting better than 50mpg on a regular basis (remember, the HF was sold almost 20 years ago, way before today's push to build more economical vehicles).

The EF8 SiR in Japan, meanwhile, was the second platform to receive a Honda VTEC variable valve timing motor (after the Integra), a DOHC 16-valve B16A. The car also boasted standards like alloy rims and A/C (oooo - exotic!), and was marketed to performance enthusiasts with optional equipment like ABS and an LSD. But the crown jewel of the trim was the B-series bullet, which produced a still-remarkable 100hp per liter of displacement. Of course McMaster's CR-X is a little of both of these cars, and then some. The HF's ED chassis foundation was gussied up with add-ons like a legit EF8 front end, doors, mirror block-offs and window visors. In the cabin, an EF8 gauge cluster stares back at the driver, a thematic touch that has as much to do with function as looks.

The EF8 cluster was part necessity because under the hood sits a bit of modern Honda wizardry that came in neither the HF nor the SiR: a K20Z1 engine and gearbox. The power train combo is native to the 2005-06 Acura RSX, and requires using the electrical JDM parts to work properly (the speedo in the USDM car is mechanical and largely incompatible with the K motor). Swapping in a K-series mill also required HASport engine mounts and a completely reconfigured fuel system. All K motors operate a return-less fuel system and at a constant fuel pressure, while Honda's last popular engine swap, the B-series, uses a return and pressure that varies according to intake manifold pressure.

To address these issues, McMaster set up a Chase Bays Fuel Line Kit and Walbro 255lph pump to feed an Aeromotive regulator, first passing fuel through a Trick Flow filter. Pressure is set and gasoline goes out to a Golden Eagle Pro Series rail, while excess from the FPR goes back to the tank via return line.

Further considerations McMaster had to make for his engine relocation bid consisted of a Karcepts shifter kit, Drive Shaft Shop 2.9 axles, and Hondata K-Pro engine management. The swap is kept insanely clean thanks in part to a killer wire tuck and the Chase Bays Mil Spec harness.

With the K-series beating heart transplanted, McMaster looked to improve engine output with Skunk2 Racing cams, valve springs and retainers, and a number of bolt-ons. Power is transmitted through a Kaiten nine-pound flywheel to the trans, where a Quiafe LSD pushes it out to the front two corners. With a proper tune, the CR-X now makes an impressive 242hp and 176 lb-ft of torque.

In keeping with the spirit of the SiR, and to optimize the new power plant, McMaster made several tweaks to the chassis, like replacing the factory bushings with new ones all around, running an ETD Racing/K-tuned traction bar, and limiting flex with a Benen rear lower tie-bar. A Safety21 seven-point cage serves as rollover protection, while Skunk2 ProC coilovers give the Rex its current low-slung stance and road-gripping agility.

With all this effort being applied toward moving fast, at some point McMaster had to think about how to rein it in. The SiR had an ABS option, but the HF not so much, so to remedy this the owner slapped on some Brembo rotors, PBR ultimate ceramic brake pads and Earl's steel-braided brake lines, with ATE Super Blue brake fluid coursing through them. Not wanting to clutter under the hood, McMaster also used a Chase Bays Stainless Steel Brake line relocation kit to move the proportioning valve.

Like the EF8 CR-X SiR, Chase McMaster's ED HF is today a Honda enthusiast's dream car, designed for a higher calling than just miserly transportation. Luckily, almost anyone with the right resources and knowledge can have one, too, thanks to companies like McMaster's Chase Bays. His Rex makes the most of both platforms, with just the right amount of modernization to keep it fun for years to come.

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