Stock motor + run time

[dugrant153]

Hi,

I currently have a Green Machine 2. I recently added purple Trinity springs which gave me some torque, but decreased my run time quite a bit.

For dirt rallying (with a rally car), its better to have more torque isn't it? I was thinking of buying a P2k or something similar (which was designed for torque) and selling off my Green Machine 2. No doubt it's an awesome motor, but the high RPMS really sucks up my run time and isn't suited for the rally stuff that I do.

Should I go to lighter springs on my GM2, and then gear down as much as I can? Or keep the thick motor springs and just gear down as much as I can? Or should I just get a P2k?

[SteveK]

Try a P2K: I hear the difference in those two generations of motors is remarkable. On the HPI forum, the P2K was the choice of almost all the Rally drivers.

[Lapster]

Yes, the p2k2 is a very good motor. They almost make my B3 wheelie on a fresh charged battery. You will be able to gear up a lot. You will have a lot of options with that motor. It is the greatest.

Anothr good motor, although not as high torque is the Reedy MVP. It has a good mix of torque and rpm. Eithe motor will be great.

[dugrant153]

So my GM2 is not a good motor to go with for what I'm doing?

Could I possibly tune my GM2 to be able to get P2k run time as well as torque? (well, not completely the same, more importantly is the run time).

[highroller]

The GM3 is still fine for your purpose, knowing what a motor's power band is, is the way to tune or gear it.
Generally the power band on the GM3 is high rpm, low torque, low efficiency compared to other stock motor, the MVP produces the best numbers but relative HP (watts) are still roughly the same with all stock motors. The HP is the determining factor of how fast a motor is.
To get the GM3 to run in offroad or touring car gearing it lower than a typical stock motor is the way to help the Torque come in. Then to fine tune using a full face brush med or low silver brush, and finally tuning the spring tension Red spring with 5 degree bend, and Green spring on Negative. Not using comm drops, but ice (or freezing) to keep the motor cool will help the efficiency of the motor. The motor will run stronger if you are able to keep it from building up heat.

The RPM and Torque output are used more for gearing a motor to suit the track size, while HP (watts) is used to determine how much faster another motor is over the other(a 1-10% diff can make a big diff in overal speed), efficiency determines how well the motor is one using energy to produce it's power or wether or not you will have enough battery to suit the power needs of the motor.