I have done it with a buggy, a Cybermaxx and a Mammoth, all 4-wd. It is very hard to do with a 2 wd. The size and wieght of the tires is a big factor, the heavier they are the easier to flip. The mammoth has huge tires and I actually double flipped it with ease, and even had to brake to prevent a 2.5. I just roll up to the jump at about half throttle, then hold it pinned from the base of the ramp until it rotates around. Try to let off the gas before it hits to reduce shock on the drivetrain. You don't want to be at full speed when you hit the jump because you need to further accelerate the tires to rotate the car.