Water Pump Racing Modification

[jtb0322]

I have read somewhere in a magazine, I forget where, that circle track racers have taken the impeller out of the water pump and cut a few fins off of it to reduce drag put on the motor. I cannot find this article anywhere I look now but I know I have read about it. They said that on the track you are typically turning about 4000-6500 rpms and at that speed the water pump is actually pushing to much coolant through the motor. By eliminating some of the fins, this lightens up the stock water pump and reduces drag on the motor? Is this a good idea or not?

Also, does anyone sell a stock appearing ball bearing water pump?

Thanks!!!

[clay]

Not sure what you're asking about the ball bearing pump as all of them have ball bearings - no way they could survive belt tension for that long with anything else. Here in an excerpt from an article mentioning the modified water pump. You might try searching for "sealed engine" or "crate engine" as they have several tips that you might find helpful.

[jtb0322]

Thanks for the link to that article!! I knew I've read about that somewhere! Does anyone have any experience on doing this to a water pump? I'm trying to make the most out of what I have and a few little things like this can make a small improvement. I realize all water pumps have ball bearings so let me restate my question... Does anyone sell a racing quality pump inside of a stock appearing housing? Thanks for the help!

Does anyone have any other little tricks like this to reduce drag/friction on the motor and increase power?

[Big Dave]

Most racers use a Stewart phase III or higher stage water pump as they move more water than stock pump (which is good) but at one third the horsepower drag of the stock pump (which is even better). It does this by using a CNC machined fully enclosed scroll instead of an open paddle wheel found in the stock pump. The Stewart pump has a larger diameter drive shaft (which requires opening the hole in your water pump pulley to BBC size) which is also used on the Corvette small block motor.

Big Dave

[motorman]

i remove every other fin from the impeller to prevent cavitation on high RPM race car engines

[af2]

[motorman]

[Paul P]

[motorman]

cavitation at high RPMs is the reason because a pump designed to cool a engine at 2000/3000 RPMs cavitates at 7500 RPMS unless it is modified. now days there are after market race pumps but years ago they were not available so as a engine builder you did what you had to do to cool the race engine

[Paul P]

Like one of those plate kits that can be riveted to the impeller to help cavitation. Yup I agree there are purpose built pumps that have a greater rpm range and don't cavitate.

[motorman]

those plates are used on stamped steel impellers that late model water pumps use and i was modifying cast iron impellers

[Paul P]

If I remember way back that the plates were for the older cast impellers to make them efficient like the newer plate type impellers. You can't rivet to the edge of a steel impeller. Anyway they don't sell them any more I just looked. Sort of beating a dead horse at this point.

[motorman]

cast iron impellers were solid on the back side not open like the stamped steel ones because they bent the metal to form the blades which caused the openings

[Paul P]

That's what I was looking for and couldn't find. Thanks. I am having a senior moment. Sorry .

As a tech inspector you must have seen some stuff most of us could not even dream up. Again my apologies for my reverse thinking on the application of the old plates.

[motorman]

no problem as at my age 78 i have CRS "can't remember s--t" some times