Originally Posted by Korey Harbke

I agree with Scott, the motor sounds liek it is undergeared. Go with his gearing suggestion and you should be closer to the ballpark ratio you need.

FYI, you don't really NEED the 18T pulleys. It just changes the internal ratio of the car so it doesn't require super huge pinions to get brushless motors geared correctly. They also have some added benefits of not bending the belt as much, so they free up the drivetrain a tiny bit. Even then, we still have to run some pretty huge pinions to get brushless spec motors geared properly.

-Korey