Prescription 4 Performance
Ray Garbalosa's 1974 RX-4 Wagon
The R100 and RX-2 were Mazda’s rotary trailblazers in the American market, hitting the scene in 1971. The RX-2—powered by a 120-horsepower 12A rotary—enjoyed more sales than the R100; a commuter car at heart, the RX-2 was joined by the sportier RX-3 in 1972. The RX-2 was discontinued in 1974 when Mazda rolled out the RX-4 on American shores. The RX-4 represented a more luxurious take on the rotary phenomenon and featured a then all-new 13B engine.
Both the RX-3 and RX-4 left the lineup in 1978, replaced by the first-gen RX-7, but before leaving these early RXs forged quite a reputation on the track, racing under the Sports Car Club of America (SCCA) and International Motor Sports Association (IMSA) banners. So there is a legacy of respect that goes along with the early RXs, making them prime customization platforms for fans of the “old school.”
Ray Garbalosa and his seductive 1974 RX-4 wagon serve as beacons for old-school cool. The paint is original, but Ray has made a few tasteful upgrades to set his Mazda off. Up front Ray added a bumper from a '74-'75 RX-4 coupe and a custom valance conversion. The rear has been dressed with an Australia- spec 929 bumper.
The biggest changes are under the hood, where Ray cheated time by swapping in a newer version of the 13B rotary. The RX-4 is motivated a 1989 to ’91 RX-7 Turbo II version that was originally factory turbocharged. Ray relocated the engine, positioning it back nine inches from stock to attain a balanced 48/52 weight distribution. The engine features an FD (1992-‘98 RX-7) upper intake manifold and throttle body, FC Turbo II lower intake manifold, GReddy intake elbow and a trick custom tubular exhaust manifold.
The manifold utilizes divided runners and dual 38mm wastegates, one for each rotor, and secures a Garrett T04B turbo with a .84 A/R divided turbine housing and P-trim turbine wheel and a H-trim compressor wheel in a .70 A/R compressor housing. Spent gases are evacuated via a three-inch full stainless exhaust with Racing Beat stainless silencer and muffler. The cold side sports a 10.5x24x3.5-inch intercooler, 2.5-inch piping and a TiAL 50mm blow-off valve.
It is critical that a boosted rotary has enough fuel capacity and Ray did not flinch, installing 700cc primary and 1000cc secondary injectors, Malpassi fuel pressure regulator, Bosch fuel injection pump, 3/8-inch and dash-6 AN fuel lines and a Mallory low-pressure pump for the surge tank. As critical as fuel enrichment is, today’s modern fuel-injected engines are only as good as the engine management system that runs the show; to this end Ray called on a Microtech LTX-8s computer designed especially for the unique requirements of rotary engines.
The suspension received a modern update as well. Ray started by installing an FC front suspension and rack-and-pinion steering set-up. He then added Tokico five-way adjustable front shocks with a Ground Control adjustable coil-over spring kit. Side loading is limited by adjustable Speedway Engineering sway bars front and rear. The rear suspension features Afco coil-overs on a conversion using a three-link setup with an eight-inch Ford solid rear axle. Ray has kept his rolling stock “in the family,” choosing a set of five-spoke alloys from a stock FD RX-7.
Inside the cabin are an eclectic mix of 1970s and 2K11. This contrast can be seen in the difference between the stock rear seats and the ultra modern RX-8 buckets but is profoundly evident on the dash, where a high-tech LED air/fuel ratio readout from Innovate is nestled next to the Mazda’s original ‘70s vintage fuel level gauge. Ray has done a nice job mounting an array of Autometer gauges in a carbon fiber housing.
The old school trend is hot these days, and Ray’s RX-4 has a unique mix of vintage and modern that clicks. Smooth boosted rotary power calibrated from a leading edge computer dropped in a classic old school shell this prescription for performance delivers the goods.
Ray Garbalosa's 1974 RX-4 Rotary Wagon
Engine & Accessories
89-91 RX-7 Turbo II (FC, S5) 13 B
Garrett T04B turbo
Custom tubular exhaust manifold
Racing Beat stainless silencer
Racing Beat stainless muffler
GReddy intake elbow
700cc primary injectors
1000cc secondary injectors
Bosch fuel injection pump
Malpassi fuel pressure regulator
Griffin 24" x 19" double pass radiator
Sweet Mfg. power steering pump w/ remote reservoir
Microtech LTX-8s tuning computer
S5 Turbo II transmission
Mazdatrix clutch & pressure plate
Ford 8" rear end
Auburn limited-slip diff
FC front suspension and rack and pinion steering
Tokico/Ground Control coilovers
Speedway Engineering front & rear sway bara
3-link rear suspension
AFCO coilover shocks
Wheels, Tires, Brakes
'93 RX-7 (FD) 16"x8" aluminum wheels
FC 4-piston front disc brakes
2001 Ford Mustang Cobra rear disc brakes
'74-'75 RX-4 coupe style front bumper
Custom valance conversion
Australia spec 929 rear bumper
Momo steering wheel
Autometer oil pressure
Autometer oil temp
Autometer water temp
Autometer fuel pressure
Innovate Wideband w/display gauge
Blitz SBC-iD boost controller