Different water pump impellers

[wsa111]

Has anyone done any homework or working experience on the 2 different water pump impellers which come on reman water pumps??

There are the cast impellers with a cast backing or mounting surface for the impeller blades.

Then there are the stamped steel impellers with no backing just open blades.

I know years ago a company offered a sheet metal circular plate for the various manufacturers that pop rivited onto the open impellers & were supposed to increase flow 25%.

Just wondered if anyone has some direct experience with both type of impeller designs as far as flow & cooling ability.

http://go.jeep-xj.info/HowtoWaterpump.htm

http://www.flowkooler.com/

This is just an example. Bill

 

[wallaka]

The ones with the backing plate are the ones for the cars with A/C and are more efficient from all reports. There is more heat in the system with the radiator blocked by the evaporator so I am pretty sure it is true. Otherwise it is pointless to change the part..

I don't have any way to measure it, but I'd go with the factory HD part.

 

[65coupei6]

I compared the two a few years back when I swapped my pump. The aluminum pump with the stamped steel is the better or the two. Except at the parts stores the aluminum & iron pumps go by the same part numbers. So, you just have to go thru a few boxes before you find the one you want.

Once I installed the pump. I noticed a temp drop. Don't remember the exact number. Then I added an aluminum pulley which helped even more.

Plus, the aluminum one polishes up nicely





The chromed TStat housing just finishes everything off nicely.

 

[addo]

You need to run mercury for coolant, then it will be shiny on the inside as well. A clear expansion bottle could really top things off.

 

[addo]

My gut feeling was that pump impellers of pressed metal did work a little better. Then again, we were usually replacing a worn-out cast impeller unit!