Neodymium Magnet Upgrade Review
These Neodymium Magnets were purchased from a website called Team MNM the Installation is pretty well straight forward assuming you've pulled apart your Xmod a few times, the actual installation of the Magnets is also fairly easy and you can use this tutorial Here
You've Installed Them, what's the Big Deal
Well lets start with a little bit of theory, a motor consists of two permanent magnets (the ones were are installing) and an armature which is an electro-magnet (becomes a magnet when power is applied) The strength of the magnetic field generated by the permanent magnets in the motor determines how much energy is required to overcome this field and cause the armature to spin, this translates to 'Torque'. Torque is the amount of force the motor can apply to the pinion gear to force the wheels to start turning, so the stronger the magnetic field created by the magnets the more torque it creates.
Why is torque a good thing?
The reason its very important is that it compensates for a big problem that we have, one speed no transmission! Basically when you purchased the Stage 2 motor kit you noticed you got 4 motors, each motor is exactly the same it spins at 30,000 rpm same specifications the only thing different is the gear ratio! you have different size of pinion gear on each motor.
- 8 Tooth Drift Motor and gearing for maximum torque.
White Gear/Motor Combo = Ratio of 6
- 9 Tooth Drag Motor and gearing for balanced torque/horsepower.
Red Gear/Motor Combo = Ratio of 5.11
- 10 Tooth Road Race Motor and gearing for balanced torque/more horsepower.
Yellow Gear/Motor Combo = Ratio of 4.40
- 11 Tooth Top Speed Motor and gearing for maximum horsepower.
Blue Gear/Motor Combo = Ratio of 3.82
The best Ratio would be a 1:1 Ratio which would mean for every turn the motor makes the wheels would turn once! a Ratio of 6 means the motor turns six times for every one time the wheels turn. so when a lower Ratio is used the motor requires more 'torque' to get moving, a higher Ratio means the opposite the motor can spin-up easier and get things moving much faster. The whole key here is that the Ratio also affects one other thing big time, your top speed! Have a look at the Chart below.
|Stage 2 (30,000 rpm)
|WHITE 8 tooth
19Km/h (11.8 MPH)
|RED 9 tooth
21Km/h (13.0 MPH)
|YELLOW 10 tooth
24Km/h (14.9 MPH)
|BLUE 11 tooth
26Km/h (16.2 MPH)
From this Chart the best speed is with the 11 tooth gear but if you use it your ability to launch quickly is taken away because of the very large amount of Torque needed to get the car moving, in the real world we have transmissions with multiple gear Ratios which solves the problem. The best combination would be to be able to use a 11 tooth motor but have enough torque that the car would be launched as quick as the 8 tooth combination!
So now do you see where we are going with this
This simple $6 upgrade transforms your motor into a little 'Torque Beast' you get the top speed from using a 10 or 11 tooth gear but it will launch itself as fast as the 8 tooth gear! The biggest advantage is that you do not need to touch the electronics or alter your current battery set-up (4 AAA's) of course if you forget to mention your little upgrade the Xmod will pass any inspection by your friends. They'll figure it out eventually but it'll be worth it to see them try and figure out why your thumping them in all the races!
Considering the low cost I can't see anyone going wrong with this upgrade so I give it my full recommendation! I have to mention that this little car moves so damm fast now that I honestly don't know how anyone can control these things I can't even image what would happen if I added Cells or upgraded to Li-Ions!
I hope this review was helpful