more than likely a valve!
Pipes make a knocking sound when the water is turned off due to a phenomenon called water hammer. This happens when the flow of water is suddenly stopped, causing a pressure wave to travel through the pipes and create the knocking noise.
it might be the cv axel boots
When forces are unbalanced, there is a net force causing an object to accelerate in the direction of the greater force. This acceleration can result in a change in the object's speed, direction, or both. The object will continue to accelerate as long as the forces remain unbalanced.
An expert would have to hear the sound for a diagnosis. It may be your main bearings are knocking. If it also happens if you lift your foot sharply OFF the accelarator, then that's a sure thing. - Only way to check for sure is to fit an oil pressure gauge.
Pipes can make a knocking sound due to water hammer, which happens when water flow is suddenly stopped or redirected, causing pressure to build up and create the noise. This can be caused by loose pipes, high water pressure, or a faulty valve.
If an object is not in equilibrium, it will experience a net force acting on it, causing it to accelerate in the direction of the force. This acceleration will change the object's velocity and possibly its position.
It goes faster
The object will accelerate.
If the net force acting on a motionless object is not zero, the object will start to accelerate in the direction of the net force. Newton's second law states that an object will accelerate in the direction of the net force applied to it, causing a change in its velocity.
If it only happens when you accelerate the most likely cause is an axle.
Knock on wood means you are hoping that it happens.
Rear U-joint causes knock. happens to almost every 300zx. mostly noticed in automatics. I have owned all z31 zx's 84-89 except 88. it will not damage anything, you can put 200k miles with this knock. Just annoying. Steve the Zman