Re: why does the truck lift up
Most direct engine torque goes into motor mounts and dissipates as heat.
Its just physics.
Now that I would like to see!!! Those suckers would be glowing white hot! That's not physics, that would be magic!
It's not the frame twisting on a semi. It's the torque of the engine making the front suspension raise.
I can see how this could be. You could saw off all the motor mounts, then put a board across the frame to support the front of the engine. Then you run a chain from the lower front suspension arm to the top of the engine. Then when the engine torques around, it wraps the chain around itself and lifts the suspension! This way it never twists the frame until the suspension hits the upper stop.
In the real world, Newton's 3rd Law applies:
''To every action there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions''
This was first published on July 5, 1687, so it's only been around about 332 years.
If a torque is exerted on the driveshaft of 21,000 lb ft, using QC's example, then the engine is trying to rotate in the opposite direction with a torque of 21,000 lb ft. Since the engine is bolted to the frame, the frame has to resist this 21,000 lb ft. If the frame rails are 6 feet apart, this is the same as pushing down on one frame rail with 3,500 lbs while simultaneously lifting up on the opposite frame rail with 3,500 lbs. So the frame twists, raising the suspension on one side. This is the same reason the frame is twisted on the picture of the dragster doing a wheelie, and also the reason the right rear tire is planted harder than the left rear tire. There's a big down-load on the right frame rail, and an up-load on the left frame rail.