Ok Rusty, Lets be clear here, the reason to run an underdrive pulley isn't to reduce FLOW. The reason is to prevent CAVITATION. This is dramatically different than trying to reduce flow.

The ads for the pulley's say they reduce wasted power, and reduce the chance of cavitation.  Perhaps the only significant advantage is the reduced chance of cavitation, but that's not how they're advertised. 

Since you are using the EWP as a backup (which seems a sound idea) you aren't sure it will do the whole job.

The best way to make me prove that it will work, is to keep telling me it won't :-)  

Seriously, I'm quite happy with my current system.  It's really the best of both worlds, but it would still be valuable to prove (to everyone else) that the EWP will do the job all by itself.  I'm already quite convinced that it will, since I've tested it on the ground (at a voltage disadvantage no less).  

Since I'm changing to Evan's, and expect a performance reduction in the cooling system already, it makes sense to run the system just like it was first as a baseline, then try to find a way to test the EWP by itself.  The skeptics will be happy to know that it will be nice and hot by the time I get around to such a test.   

Bill Jepson (Still skeptical, But willing to listen.)