I’m using WheelJoint2D and my car can’t climb small hill. But my car should climb big hills (like in HillClimbRacing). So, How I can increase the car power without increasing speed?
Advance thanks 
the power of a wheel is basically called torque. Raising torque however will also make your wheel able to accellerate faster. So in some way this can (if you don’t limit it manually to some max speed) allow players to get to higher speeds.