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 |   |  1989 FC3S Mazda RX-7 - JRX 20B T88 FC3S RX-7
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1989 FC3S Mazda RX-7 - JRX 20B T88 FC3S RX-7

Code talk for import power.

Luke Munnell
Nov 23, 2010

It's a warm July evening in Irwindale, CA, and Toyota Speedway is lit bright as day. It's Thursday and the thunder of revving V-8s blasting eighth-mile passes at the weekly Test and Tune session can be heard for miles around with the same intensity as it can be felt up close. I've been there many times before, watching tuned imports run side-by-side with these domestic rivals (and usually faster), but tonight I only catch a glimpse of it from the 605 freeway. Tonight I have more pressing engagements in Irwindale.

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I roll a few miles past the legendary "House of Drift" to the parking lot of JRX Rotary, where in front of a huge bay door entrance stands Juni Asuncion, backlit by a mix of fluorescent lights and the intermittent sparks and welding flash of a shop that never sleeps. It's his place, at about 7:30 p.m., and he's only halfway through his work day.

Juni stands over six feet tall, with the athletic frame of a Major League pitcher. Eternally of a calm demeanor, he speaks with a confident voice, collected and concise with his words. He admittedly avoids the spotlight, and as an I.T. professional in a previous life, possesses far more broad-spectrum knowledge than he lets on. With sunglasses on and a cigarette lit, one might take him for a total badass if not for the fact that approachability and customer service are two of his strongest, hidden attributes. "Park wherever you can find a spot," he tells me, pausing his phone conversation to do so. "He should be bringing it around any minute." And then with a grin, "Walk up toward the street. I'll tell him to get on it."

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No sooner do I get in position that I hear it. Approaching in the opposite direction of raspy four-cylinders and growling small blocks heading off to wage war at the strip, a coalescence of confused engine tenor fills the air. First, an exhaust note similar to that of a muffled, high-revving Ferrari V-6 grows in the distance. The unmistakable crack of pressurized air exiting a blow-off valve at throttle let-off cuts through it, followed by the rushing sound of boost building under a floored throttle as the beast nears-sonar evidence of turbocharging in the mix. Then, within sight if not for the white glare of HIDs, the scream of what sounds like a belt-driven supercharger straining to keep pace with five-digit rpm commands attention as a bright blue blur flies past at what seems like triple-digit speeds, its automotive symphony playing in reverse as it disappears from sight.

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"There it goes," utters Juni with a casual nod.

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"WTF was that thing?!" I shout across the parking lot. He just stays in his spot and lets out a laugh.

As I walk back to demand answers, the owner of a Lamborghini-blue FC RX-7-endlessly clean and slammed on flush-fitting, polished, 19-inch SSRs-parks his ride and wanders off to the adjacent body shop to chat with its crew. "That's Anderson, the owner," Juni tells me. My mind floods with a thousand questions for him: "Where do you live? What do you do for a living? How much friggin' money did you sink into this thing?!" Juni can sense it. "He's a cool cat, but it's probably best to let him do his thing," he says with another nod in Anderson's direction. "Come on, I'll tell you everything you need to know."

Juni and the JRX team are responsible for nearly every proper modification made to this beast. Keyword being "proper", because it wasn't always this clean. "Anderson had been to a few shops before finding us," Juni begins, "and it was a mess when he brought it here." Popping the hood reveals the source of the audio amalgamation heard earlier: a 20B three-rotor engine and T88 turbocharger, good for just over 600 hp at the wheels. "The engine was installed at a previous shop," he says, casually. "But Anderson left them after they messed up his V-mount and filled the engine with used oil to get it out the door." The V-mount-which was more like an "H-mount" as Juni described it-now consists of a Koyo radiator and custom intercooler core, end tanks, and plumbing, properly set up to maximize cooling efficiency. In between the new setup and the 20B I find the source of the belt-driven whine I couldn't identify earlier: a ribbed Gilmer-drive belt and pulley set for the crank, alternator, and water pump, added to eliminate slipping in peripherals that can barely keep pace with one of the fastest-revving engines in production.

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"We ended up re-doing the mounts, wiring, V-mount and piping, turbocharger, tuning . . ." Juni continues. "Everything." Juni tore the 20B apart while it was out during motor mount fabrication and machined its stock rotors to accept Hurley ceramic apex seals. He custom fabbed a manifold to attach the giant T88, along with a turbo-back exhaust and wastegate dump, and polished every bit of aluminum he could find underhood. An Earl's oil cooler was wisely thrown in, the fuel system was upgraded, and the whole mix was tuned in-house with a tried-and-true Microtech LT12s; it's a rotary thing, in case you're wondering.

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Mated to the 20B-which is native only to the automatic '90-'95 Mazda Cosmo of Japan-is the FC's stock Turbo II five-speed transmission, adapted by Juni to fit, and reinforced with an Exedy triple-plate clutch and flywheel. The FC's factory driveshaft (also adapted in house) and rear-end were also retained, but the suspension is a lot less stock. Tein Flex coilovers form the base of the makeover, followed by a complete suspension bushing upgrade and the addition of a Racing Beat rear sway bar, custom front sway bar, and an Autopower roll cage, with Rotora four-piston brakes and lines rounding out the footwork-perfect upgrades for a fast street car.

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The interior sees the requisite Recaro bucket seats, harnesses, and Momo odds and ends, but also a few surprises: a Microtech DASH display unit and trio of Defi/AEM gauges custom-mounted in the center console, positioned just above a Kenwood head unit that tastefully contrasts an otherwise full Memphis Audio I.C.E. system. But behind the driver's seat are the real goodies: an Aeromotive high-flow fuel pump, custom swirl pot, and reservoir for the AEM water/methanol injection system Juni installed as the FC's final mod (to date, anyway). "It's not a track car; it's a street car," Juni advises. "It could make a good track car, but that's not what it was built for."

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Anderson strolls back to his car as Juni and I finish our conversation, and despite my better judgment, I quiz him on his background information. He's an L.A. O.G. who's been in the scene since building his first car-an '85 RX-7 now being re-worked by Juni-for the infamous Sylmar street races back in the day. His business is his business, and while he's every bit as friendly and genuine as Juni, I get the impression that I wouldn't want to cross him. Our conversation begins to die down as he answers a question I hadn't yet asked. "Now that the car's done, I really don't know what else to do with it." And, as if on cue at the end of his words, one last built V-8 rumbles past and he and Juni exchange an understanding grin. "The first thing I'm gonna do is give those f-ers a run for their money!"

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Behind The Build

Anderson Cheng

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Los Angeles, CA


Build time.
Two Years


This is it!

"It's a rotary thing . . . you wouldn't understand."

'89 FC3S RX-7

Output: 600 whp @ 14 psi
Engine 20B conversion; Hurley ceramic apex seals; custom porting; Precision T88 turbocharger; AEM water/methanol injection system; HKS blow-off valve, wastegate; Greddy Profec B-Spec II boost controller; Gilmer-drive accessory pulley system; Koyo radiator; Spal fans; Earl's oil cooler; custom turbo manifold, downpipe, V-mount radiator/intercooler system, intercooler piping, velocity stack, oil catch can, radiator overflow, AN fittings/lines; Microtech LT12s engine management system; Bosch ignition; NGK plugs; RC Engineering 850cc/1,600cc fuel injectors; Aeromotive fuel pressure regulator, inline fuel pump; Walbro in-tank 255Lph fuel pump; custom fuel rail

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Drivetrain Exedy twin-plate clutch, flywheel

Suspension Tein Flex coilovers; custom front sway bar; Racing Beat rear sway bar; Autopower roll cage

Wheels/Tires SSR Professor SP1 wheels (19x9.5 +25mm front, 19x10.5 +28mm rear); Yokohama S-Drive tires (245/35-19 front, 285/30-19 rear)

Brakes Rotora four-piston front brakes, custom stainless steel brake lines

Exterior Shine Auto Project front bumper, rear bumper, side skirts; JRX Wangan carbon fiber wing; Lamborghini blue paint, applied by Zoom Tires

Interior Recaro Speed seats; Momo Tuner steering wheel, shift knob, e-brake handle

Electronics Defi gauges (oil pressure, water temp, boost, tach); AEM UEGO, Microtech Dash display; Ignited engine start button; Kenwood KDC-MP638U head unit; Memphis Audio Power Referee amplifiers (x2), door speakers (x2), subwoofers (x2), wiring

Gratitude JRX Rotary, Advance Speed Shop, Zoom tires, Memphis Car Audio


Memphis Car Audio
Memphis, TN 38103
JRX Rotary
Zoom Tires
Shine Auto Project
Advance Speed Shop
By Luke Munnell
304 Articles



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