Original Year
# of pieces
Cars & Trucks: Buggies
(without gate)
Motorized, suspension,
breakaway engine
Other Views

8279 4WD X-Track

iso revolve
Click the image to download the LDraw file of this model.
Model by marco9999

This set was a dramatic departure from traditional Technic, but there was nowhere else to put it in 2000.  The following year, the new Racers line would become the home for this kind of model.  This is a very simple motorized play set.  The "4WD" in the title is accurate since this buggy is actually four wheel drive, but the "X-Track" is a bit of a mystery.  There is no track and therefore there is certainly no X, but the model does drive and has remarkable power and durability.

As a play set, this model does more than just drive.  Although it can overcome considerable obstacles, it can also be used in competitions using the included finishing gate.  Instructions were also included for alternate configurations which could use the Supplemental speed computer.


This set included the first instance of the "BUMP" or Big Ugly Motor Piece.  This large monolithic block contains a battery box for 3AA batteries, an on-off switch on the bottom, a polarity switch on the top, and a pair of outputs.  The lateral hole through the rear of the block can be used to drive an axle, as can the longitudinal hole at the rear.  The rear output is geared down more and is used to power this model.

One might reasonably ask why this thing needs to be so big just to house one motor.  It doesn't.  As can be seen in the third image, the interior is mostly empty.  The part is made to be turned into a car with minimal effort.  Add a an axle to the front and back and you are ready to go.  The image also shows a fascinating combination internal ring gear and pinion gear used for large reduction.

At only 4.5V, you might think this motor would not have enough power to actually drive a model.  However, it has quite remarkable power and moves the vehicle very well.  As can be seen in the computer image, the white output is geared down a further 3:1 at the blue 24 tooth gear, and then the rest of the drive train is a very simple 1:1 with no differentials.
bump    bump

bump    bump
The model has a rear mounted V-4 engine with transparent cylinders.  This is not a functional engine in that it has no pistons or crankshaft and is not connected to anything.  It is there only for play value.  When the cross axle at the rear hits an obstacle, rubber bands eject the engine.
engine    engine
This model has very simple unsprung pendular suspension at the front.  This doesn't absorb any shock, but does help keep all four wheels on the ground over uneven terrain.
Finish Gate
Parts and instructions are provided for a gate.  The power switch for the BUMP is connected to a long vertical axle.  As the car passes under the gate, the axle hits the cross beam and shuts off the car.  If the adjustable stops on the vertical beams are also extended into the gate, the engine will be ejected.

The car is quite fast and has no steering, so getting it to go through the gate from any distance is quite difficult.
Wheels and Tires
This set uses 4 of the  56x30 balloon tires and the  metallic silver painted wheels.  It also uses uncommon 5.5L white axles.

Other Views

Side View
side view
Top View
top view
Front View
front view
Back View
back view
Computer Render

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