Iam currently teaching myself how to use and create particles, therefore i wanted to re-create some effects from the [UE4 documentary here][1].
But when i, for example, hook up the ParticleRelativeTime constant to the Emissive Color, or any other particle constant code (ParticleWsPosition, ParticleDirection, ParticleSpeed, etc) nothing changes aka the particle stays black and looks like this:
Here is the Material the Particles Use:
And those are the modules i use for the Particle Emmiter System:
What am i doing wrong? 
I dont want to change the color via ParticleColor node, that works fine, also for the Opacity.
Only the remaining Constants have seem to have absolutely no effect, and i need them to work for further testing and particle behaviour which i want to test