Hey OhiraKyou -
What are your Source and Target settings in the Beam Emitter set as? You should be able to set up a relative location check on a source object (your vehicle) and a random point (you can create a target point in the blueprint to use as a reference) in from of the vehicle. By doing this setup in your blueprint you should have complete control over your beam without absolute position/location lagging.
Thank You
Ketchum