Shave the water pump
 

Not save it, shave it, the impeller blades. Odds are none of you are going to do any racing and even with reduced flow it would be more than adequate on a hyper miler. It would help increase warmup time to the cylinder, and it would be substantial savings not having to move the coolant around as much. Think of I as a water pump, if it can flow 1000 gallons a minute to keep a car cool on the highway in the desert without aero mods then a educed fuel efficiency vehicle would need half, 500 gallons a minute.

Or remove the belt and run it off of an elctric motor with variable speeds

Sort of like adding an under drive pulley but a bit more extreme.

Easily tested, warm up an engine and check on scan gauge how much fuel is consumed. Remove Belt and test again

i think under drive pulleys is a simpler, better way to achieve this. It lowers the speed of other power consuming devices at the same time.

If you are a machinist and can do this job properly, give it a whack. Won't cost much other than time.

Not so sure I'd want to try it... unless I had another pump lined up already to replace the shaved one with, should it prove inadequate. I think underdriving it would be a more prudent approach. If for some reason that is unacceptable, kart racers sometimes will remove every other flywheel cooling fin as a way to reduce the hp losses; that might work here too.

I run an electric pump on my diesel suburban and have a 2 speed setting. Low speed for around town and high speed for highway use.

How long/how many miles have you put on that setup?

My set up is still fairly new.
It passed the main test loaded down and pulling the trailer for 1,700 miles.
I am still going to put together a improved coolant pump, a more powerful pump with better flowing piping.

wtf, can someone get rid of this guy please,

and oil pan 4,
any increase in f/e or are you still in the testing a tuning stage

Anybody ever shave a los angeles escort?

Sounds like more fun than a water pump.

I'd be real cautious about reducing water pump flow. The water circulation is used not only to cool the engine, but also equalize temperatures throughout the engine.

Pump power is proportional to RPM cubed, so is low at the low RPM's that we drive at. I don't know enough about engines to know if reducing flow at low RPM will lead to hot spot problems.

The engine has less than 2000 miles on it so its not even broken in, I have some tuning to do and more parts to put on.
My next major MPG effecting part will be installing a turbo "F-code" intake manifold. I will be replacing my prized "J-code" intake which as proven its self to be a good set up for fuel economy. The F-code intake will be put on so I can play with water injection and so I can install a turbocharger later on.

EGT readings tell me more heat is going out the exhaust compared to the old engine so I need to advance the timing a little bit. I had to track down a special tool to properly check the timing.

So far my highway milage was looking good at 21mpg considering I had the truck loaded up with tools and parts, had a 24 foot aluminum lader strapped to the roof and was pulling my trailer.
Being down 4 to 5 mpg compared to being empty with nothing on top or being pulled behind is looking pretty good. I also had brandnew 31'' yokohama AT-S tires installed right before my trip.
I expected my fuel milage to be in the high teens for that trip.

An aluminum lader has to be the worst thing you can put on a truck for aerodynamics, I could hear nothing but wind noise coming off that lader any time I got above 50mph.