higher output water pump for the 6.5

[stezloco]

With all the talk of putting on a 'higher output' water pump, has anybody asked the question , 'will putting a smaller pulley on my existing water pump lift the output'??
there are 3 ways to 'up' the output of a water pump, 1 being increase the diameter of the impeller and 2 being increase the width of the same impeller and 3 to increase the speed of the pump rotor to impart more energy to the water...this is a method used in industrial pumps to vary the flow and head (does that translate correctly?) of a water pump...any water pump.
i'm sure it will, but i'll bet nobodys bothered to test the output....:confused:

[DmaxMaverick]

All things considered, I don't think spinning it faster will offer any gain above low to moderate engine speeds, and will likely be counterproductive at higher speeds. A modification of the impeller and/or housing could, by itself, offer some gain, and would likely be necessary to produce any gain if higher speeds are imposed.

Reason: Fluid dynamics.
The water pumps used in over-the-road application engines (specifically the GM Diesels of discussion), are centrifugal impeller, non-positive displacement pumps. This design has an inherent limitation to an RPM range of operation. The envelop of operation is narrow, and relatively specific to the operating RPM range of the engine. Outside this range, specifically higher speed, fluid cavitation occurs. This happens in an otherwise normally operating system, and is apparent in (assumed) full life components. This is the pitting and erosion you see on higher mileage use, of the pump housing, impeller, and backing plate. It is present, but at an "acceptable" level. Ideally, there should be no cavitation, but the acceptable amount is necessary under specific conditions to satisfy other specific necessary operational conditions. At, and above, the onset of cavitation, the pump efficiency declines exponentially. Faster is not beneficial, and may likely cause an efficiency decline in other areas of the system.

Cooling system optimization/improvement can be achieved with several other methods, and has proved to be effective. A redesign of the engineering, in this case I think, is not a solution.

(Tomorrow's lesson: Molecular cohesion. Another defining law of fluid dynamic limitations)

[More Power]

Good work DM!

Also, using a smaller WP pulley would increase fan speed. What would the impact be on fan-clutch life, airflow or fuel economy?

Jim

[stezloco]

thanks for the replies,,,,i'm sure theres a lot of sense and merit in what you say......
i dont have the big steel fan fitted anymore Jim, so thats not an issue for me..went twin leccy fan instead as ive always done on every motor ive owned running mechanical fans.
it leaves bags of room when you get rid of the cowling as well, my HUGE intercooler sits there now behind the fans , with a fan of its own attached and it works very well...i'll be getting rid of the dud aircon pump soon and replacing it with a mechanical air compressor soon as i work out the fitment of the electric clutch.......looks like i'll have to get the 130 w/pump and the x-over twin stat mod whether i like it or not....
cheers for the input...;)