high flow water pump.

[vettasy]

I seem to remember a thread on the pro's and con's of installing a high flow water pump. I did a search but couldn't find what I remembered.So if any one can direct me to that thread or has opinions on the good or bad effects of a high flow pump please let me know. Thanks.

 

[redmist]

Only possible downside I can think of is a slight decrease in rear wheel horsepower and cavitation at very high RPM.
If you are changing get an alumunium housing.

 

[Eric]

Links

Vettasy,

I couldn't find a thread specifically discussing the pros and cons but I did find a couple where they were/weren't recommended. Hopefully, one of these is the one you were looking for.

See the post by 80convertible in this thread.
This is a more recent thread from the C4 section but has more of a pros & cons feel. This one is also more recent from the C3 section but is more of a how to.

 

[resto75]

I remember a thread on pros and cons of hi flow oil pumps but not water pumps

 

[1979toy]

Well we can always start a thread about high flow water pumps.
My only issue with high flow pumps has to do with the bypass hole. The bypass hole is the third hole in the right side of the block. This hole goes through the pump and into the inlet area of the pump. This allows water to bypass the radiator and flow back through the motor. The only purpose that it serves is to warm the engine up faster. After the engine is warm all the bypass does is defeat all of your efforts at cooling your motor. Most high flow pumps block the bypass hole off. I would rather have the faster warmup in the winter time. Blocking the bypass also increases the water pressure I'm told, though I haven't tried to measure it. Prior to buying a high flow pump I would insist on knowing if the bypass was blocked.
I'm too lazy to have a summer and a winter (yes, I do drive on nice days in the winter) water pump and change them with the seasons. My homemade fix has been to tap the water pump bypass hole and fit a plug in the hole. The plug was then drilled through the center with a 1/4 inch drill bit to allow some water passage, but not the 1/2 inch diameter hole amount.
How important is your heater to you? Without the bypass it will be slow to warm up. If you live in the deep south that may not be a problem.

 

[Roy M]

Will put in my two cents. I was having an issue with water temperatures back during warm weather. Went with an 18" electric fan and basically no change in water temperature. I then installed a Stage II Stewart Hi-Flow water pump and this dropped the temperature about 25 degrees. They recomend installing a hi flow thermostat. Basically they take a Robert Shaw thermostat and drill holes in it so you have constant coolant flow [some] before the thermostat even opens. Did not read the threads about the cons but I am now a believer. Would not hestitate to install another one in any vehicle if needed.

 

[vettasy]

The information I was trying to remember was in a thread that 71Shark forwarded that 80convertable had started. Basicllay it was that a high flow pump pushed the water through the radiator so fast that the radiator was able to cool it as much as with a slower volume pump. Has anyone seen this?