Cen GX1 Mercedes CLK GTR

Radio Control Car Action, Aug 2002 by Bess, Stephen

track test

1/10-SCALE NITRO

PILOTING A NITRO-POWERED touring car, hearing the transmission snap into second gear and watching the car streak across an open parking lot are among RC's most enjoyable experiences. Rookies and racers alike search for fast, affordable, fun machines when it's time to lay down their cash for a parking-lot cruiser, and CEN's new ready-to-run (RTR) 4WD nitro touring car, the GXI Sport, is one such machine. The GX1 boasts dual-belt drive, oilfilled shocks, a 2-speed transmission, a pull-start NT-16 nitro engine and 13 painted body choices.

KIT FEATURES

CHASSIS. The GM's bright red-anodized, double-deck chassis is stamped from durable 6o6i T6 aluminum alloy. Plastic radio-tray posts support the zmm upper deck that houses the throttle servo, receiver (exposed and secured with an adjustable zip-tie), on/off switch and fuel tank. A 4-cell alkaline receiver-battery holder is anchored underneath the receiver and is sandwiched between the upper and lower decks. On the lower deck, the steering servo and all other components are attached to a zmm-thick chassis. The lower chassis doesn't have countersunk screw holes; that's a bummer for a competition car, but it isn't a tragedy for a parking-lot play machine like the GXi.

DRIVE TRAIN. The CEN's two-belt drive train has an atypical layout. The center pulley shaft is mounted on top of the upper deck; most touring-car designs run belts along the lower chassis plate. The long drive belt travels at 45 degrees up to the center pulley shaft, which connects the front drive train via a single short belt.

It should be noted that on the car I had, the drive train, which spins on bronze bushings, was very tight out of the box; it was so tight that the car barely rolled when pushed. Rather than strain the engine during the breakin process to free up the drive train, I used a drill to spin the layshaft until the belts and bushings turned more smoothly.

The front and rear bevel-gear differentials spin on brass bushings and use three spider gears instead of the usual two. A finger-type 2-speed transmission with plastic gears mates to a steel clutch bell, and a 3-shoe carbon clutch transfers the engine's power.

Front and rear dogbone axles with plastic wheels spin the GX1's wheels, and a single vented steel disc brake stops the car when clamped by fiber pads.

ENGINE AND ACCESSORIES. CEN packages the GXi Sport with a complete NT-16 pull-start engine with a black-anodized cooling head. The NT-16 features durable ABC construction and a 2-needle carburetor with high- and low-speed adjustments. The engine inhales through a foam-element air filter, drinks from a 75cc fuel tank that features a spring-loaded primer pump and exhales through a 2-bolt, cast-aluminum header and plastic tuned pipe with dual-exhaust outlets.

SUSPENSION AND STEERING. The GX1's 4-wheel independent suspension features lower A-arms with threaded-rod upper links. The car features adjustable threaded-rod camber and toe-in links; however, you have to remove the links to alter their lengths. Molded-plastic, coil-over, oil-filled dampers are found at all four corners. They incorporate a rubber bladder in the cap, have stiff silver springs and are attached to the shock towers and lower arms with snap-on ball studs. Fill the dampers with shock fluid before you run the car; silicone fluid of unspecified weight is included.

A dual-bellcrank assembly with brass bushings steers the GX1 Sport. The bellcranks are attached to the lower chassis plate, and instead of using attachment points on the upper deck, nylon locknuts cinch them down.

BODY, WHEELS AND TIRES. The GXi Sport kits feature painted Lexan shells with full decal sheets. The body arrives fully decaled, but you'll need to cut engine-cooling holes into the body before you install it. My GX1 Sport came packaged with a beautiful Mercedes CLK GTR body. Painted silver and with a Warsteiner/Mobil i sponsor theme, it was complete with molded side-view mirrors, windshield wipers and a Mercedes emblem on the hood.

Rubber V-tread tires with foam inserts and white nylon wheels are included. Pick up some tire glue while you're at the hobby shop, as the wheels and tires arrive unglued.

PERFORMANCE

Finding a test site for the GX1 Sport was as easy as stepping outside my front door and going to a freshly paved parking lot in my neighborhood. The lot's large, open area allowed the car to really open up, and big parking lots are where most RTR touring cars wilt spend their nitroburning time.

After I ran through a few slightly rich break-in tanks, I opened up the throttle, and the NT-16 sent the car flying. When property tuned, the NT-16 engine's dual-needle carb allows crisp throttle response at low speeds with plenty of top-end power. After a few minutes of running, engine temperatures were in the high zoo degree F range, and that's completely acceptable for a .16 engine running on 25-percent nitro.

The NT-16 also idles well and provides tank after tank of reliable bashing power. The plastic tuned pipe and aluminum header do a good job of allowing the engine to breathe well, and the pipe's exhaust note is sporty but not too loud-perfect for parking-lot bashing.