Portable demonstration apparatus and method for the comparison of lubricants and/or lubricant additives

A portable apparatus for demonstrating friction or power loss characteristics of different fluids, comprising different fluid chambers for receiving samples of the different fluids, a test shaft having different portions received in the different fluid chambers for immersion in the different fluid samples, an electric drive motor for rotating the test shaft at a substantially constant speed, piston actuated friction shoes for applying substantially the same amount of friction or force at different times to the different portions of the test shaft while the test shaft is immersed in the different fluid samples and the test shaft is being rotated at a substantially constant speed for establishing a friction or power loss characteristic for each of the fluid samples within the respective chambers, and a control system for comparing and displaying comparative data of the friction or power loss characteristics of the different fluid samples;

• wherein the drive motor includes a drive shaft that drives the test shaft, and the control system includes means for comparing, for the different fluid samples, an additional amount of current drawn or power absorbed by the drive motor or strain induced in the drive shaft when substantially the same friction or force is applied at different times to the different portions of said test shaft.