Water pump restoration with better impeller

Food for thought, but the thing I would be worried about is the extra volume of water being pumped by the more efficient impeller

has to be able to pass through the thermostat housing with an actual thermostat in place. I'm not a design engineer, but trying to figure this out

would make my head hurt! The next thing is the extra horsepower it would take to turn the impeller. Yikes! Also, you can buy all sorts of water impellers out

of a catalog if you want to up the flow just a little.

That's cool! Dang though it's expensive..a new complete unit is just over $100, but I guess if you're not gouging the numbers-resto guys you're not keeping up with fashion

zyzzyx said:

Food for thought, but the thing I would be worried about is the extra volume of water being pumped by the more efficient impeller

has to be able to pass through the thermostat housing with an actual thermostat in place. I'm not a design engineer, but trying to figure this out

would make my head hurt! The next thing is the extra horsepower it would take to turn the impeller. Yikes! Also, you can buy all sorts of water impellers out

of a catalog if you want to up the flow just a little.

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It's not the flow specifically, it's the flow at a certain pressure through a given opening ( the thermostat ). Higher pressure in the block result in less micro bubbles on the cooling jacket wall which results in better cooling because the air bubbles can't form. Remember, the temperature at the walls is at the boiling point and water can steam. The thermostat will fluctuate in orfice opening determined by temperature of the coolant coming forward from the engine block and the pump will easily flow the correct amount of coolant to drop the temperature. It takes no extra HP to run these pumps as the only friction would be water against water at the perimeter of the impeller. There is no cavitation due to the higher pressure. Also keep in mind that coolant is pumped "into" the engine, not out of the engine so you want to be sure not to have a collapsing return hose from the suction level these pumps can create. Ridding the system of air is mandatory as is a bit higher rad cap pressure (16 - 18 psi). Overflow tanks highly recommended and under these circumstances, fill the rad right to the top.

If it ain't broke don't fix it! This factory pump moves all the coolant you'll ever need.

I remember years ago seeing that spring in the lower radiator hose and thought whats this for seem like it would restrict flow. I took spring out and started car happen to rev it up and see the lower hose getting sucked closed. Always wondered how long it would have taken to figure out overheating problem if i didn't see hose collapsing. That was with stock water pump on 440. I have used flowkooler and they honored the lifetime warranty i had on the pump. It was 15 years old and they sent out new pump. Then they changed warranty period. I have read they are gmb pump bodies with there impeller design. The old big block mopar ones had aa stainless steel plate behind the impeller blades, new one they sent didn't have that feature. From what i understand they research alot on coolant flow. A guy on YouTube did flow testing on alot of mopar big block water pumps just recording how much water they moved. Perhaps if interested I'll try to post that.

khryslerkid said:

If it ain't broke don't fix it! This factory pump moves all the coolant you'll ever need.

View attachment 640597 View attachment 640598

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That's a gmb replacement water pump. Same company that makes flowkooler.

Officer Higgins said:

A guy on YouTube did flow testing on alot of mopar big block water pumps just recording how much water they moved. Perhaps if interested I'll try to post that.

Click to expand...

I remember that video. He definitely proved his point. I tried to find it awhile ago with no luck.

I put mopar performance pump on this weekend and i noticed it really doesn't flow through radiator all that better then the factory 1968 one i had on. But at rev it sends it through pretty well. I do remember the original flowkooler one moving more through at idle. But in all honesty the replacement radiator from glenray made the most difference.