In The Force Awakens Han Solo and Rey both
note that a compressor has been added to the fuel line and both agree that it puts too much stress on the hyperdrive. Rey even bypasses the compressor manually when they are not otherwise able to escape Han's freighter at light speed.
What is it about the compressor that would cause it to stress the hyperdrive? What happens when the compressor is removed? And why would someone add the compressor in the first place?
Perhaps the novelization sheds light on this.