Traxxas 74076-1 - Manual (Page 24)

24 • TRAXXAS RALLY
ADVANCED TUNING ADJUSTMENTS
When using higher gear ratios, it is important to monitor
the temperatures of the battery and motor. If the battery
is extremely hot (150°F), and/or the motor is too hot
to touch (200°F), your model is probably over-geared
and drawing too much current. This temperature test
assumes that your model is close to factory stock weight
and operates freely with no excessive friction, dragging,
or binding, and the battery is fully charged and in good
condition. Note: Check and adjust gear mesh if a spur
and/or pinion gear is changed.
This model is equipped with a Velineon 3500 motor. The gear
combination that comes stock on each model provides good overall
acceleration and top speed. If you want more top speed install the
included optional large pinion gear (more teeth). The included
optional large pinion gear is intended for high-speed running on
hard surfaces, and this gearing is not recommended for off-road or
repetitive starting and stopping.
LiPo Batteries
LiPo batteries are intended only for the most advanced users that are
educated on the risks associated with LiPo battery use. It is critical to
follow all instructions supplied by the battery manufacturer and the
charger manufacturer for proper charging, use, and storage of LiPo
batteries. Make sure you understand how to use your LiPo batteries.
See Safety Precautions and warnings on page 4 for more information..
Temperatures and Cooling
Monitoring temperatures will extend the lives of the batteries and
motors. There are many options available that will help you monitor
temperatures and cool your components .
Temperature sensor
To accurately monitor motor temperature
and prevent overheating, a telemetry
temperature sensor (part #6523) can be
installed on the motor to continually monitor
temperature as you drive. Generally, try to
keep your motor below 200° F. If necessary, increase airflow to the
motor by cutting out the rear of the body or windshield.
Heat sink cooling fan
The VXL-3s is equipped with an additional
connector to supply power to an optional heat
sink cooling fan (part #3340). The optional heat
sink cooling fan can assist in cooling the VXL-3s
in high current motor applications.
TUNING THE SEALED GEAR DIFFERENTIALS
The action of the model’s front and rear gear differentials can be
tuned for different driving conditions and performance requirements,
without major disassembly or removal of the suspension system.
From the factory, the differentials are sealed to maintain consistent
long-term performance. Changing the oil in the differential with
either lower or higher viscosity oil will vary the performance
characteristics of the differentials. Changing to a higher viscosity oil
in the differential will reduce the tendency for motor power to be
transferred to the wheel with the least traction. You may notice this
when making sharp turns on slick surfaces. The unloaded wheels
on the inside of the turn have the least traction and tend to spin
up to extremely high rpms. Higher viscosity (thicker) oil causes the
differential to act like a limited-slip differential, distributing more
equal power to the left and right wheels.
Your model will generally benefit from higher viscosity oil when
climbing or racing on low traction surfaces. Note: Heavier oil will
allow power to be transferred even with one or more tires off the
ground. This can make the vehicle more likely to overturn on high-
traction surfaces.
From the factory, the front differential is filled with SAE 30,000W
Velineon 3500 Specs
Type:
Sensorless brushless
RPM/volt:
3500 (10-turn)
Magnet type:
Ultra High-Temperature
Sintered Neodymium
Connection type :
3.5mm bullet
Wire size:
12 Gauge
Current Ratings:
200A constant
320A peak/burst
Max RPM:
50,000
Diameter:
36mm (1.42) (540 size)
Length:
55mm (2.165)
Weight:
262g (9.24oz)
The VXL-3s features Locked
Rotor Protection. The VXL-3s
checks to make sure the
motor is turning. If the motor
is locked or damaged, the
ESC will enter fail-safe until
the motor is free to rotate.
Always use the proper length
motor bolts. The standard
motor mounting bolts
are 3x8mm. Using motor
bolts that are too long can
interfere with the motor’s
rotation and damage the
motor’s internals!
7407 Rally 30+mph 35+mph 40+mph 40+mph 45+mph 60+mph
Pinion/Spur 13/54* 13/54* 19 /54** 19 /54** 13/54* 19 /54**
Battery 7-Cell NiMH 7-Cell NiMH 7-Cell NiMH 2S LiPo 3S LiPo 3S LiPo
Nominal Voltage 8.4V 8.4V 8.4V 7.4V 11.1V 11.1V
mAh 3000 mAh 5000+ mAh 3000 mAh 4000+ mAh 5000+ mAh 5000+ mAh
Skill Level 1 1 2 4 5 5
*Stock Gearing
** Included optional gear