Your Thoughts on Hi-Flow Water Pumps

[Scott Liggett]

Re: Your Thoughts on Hi-Flow Water Pumps

The only thing I want from a high flow water pump is that it moves more water at low engine speeds.

Its the only time it matters.

[TheSilverBuick]

Re: Your Thoughts on Hi-Flow Water Pumps

What about a smaller water pump pulley or larger crank pulley?

[TC]

Re: Your Thoughts on Hi-Flow Water Pumps

What about a smaller water pump pulley or larger crank pulley?

Ya maybe running a hi-flow water pump with an underdrive pulley setup might be the way to go. The pulley on the water pump on my car is pressed on from the factory, so swapping the water pump pulley is a no go. ;)

[Barry Donovan]

Re: Your Thoughts on Hi-Flow Water Pumps

Well finished up the water pump today and took the car for a drive, and guess what, it runs cooler.

So take it as you will, but on my car I feel a Hi-Flow water pump caused it to run hotter.

I believe it.

I learned the hi flows to be from days of four core radiators, trucks, gas dump trucks...
it was a need. too slow can make a thermostats just as stupid as too fast.

the hi flow part could be high volume, it just pumps more though the same openings.. tha change of course is how big the radiator is.

this can happen to any engine. a little engine doing big work for example.. go for bigger rad, same pump.. and still no good. v8 are the dramatic ones.

[yellomalibu]

Re: Your Thoughts on Hi-Flow Water Pumps

Well finished up the water pump today and took the car for a drive, and guess what, it runs cooler.

So take it as you will, but on my car I feel a Hi-Flow water pump caused it to run hotter.

I missed this thread until now, but it makes sense that a High flow pump would cause over heating issues.

Most of us know that a stock water pump pumps to fast to cool properly if you take the thermostat out, so it only stands to reason that if you are running a stock type cooling system, a high flow water pump isn't a good idea.

[JeffMcKC]

Re: Your Thoughts on Hi-Flow Water Pumps

Just as a thought is it that it goes thru the radiator to quick, or does not stay in the block long enough to take on heat??? ;)

[TheSilverBuick]

Re: Your Thoughts on Hi-Flow Water Pumps

Just as a thought is it that it goes thru the radiator to quick, or does not stay in the block long enough to take on heat??? ;)

That's my problem in the winter. I have to cardboard up the front of my Buicks' radiators because as soon as it hit's operating temperature to open the thermostat the temp drops to 130*F :o Driving down the highway watching the temp gauge swing back and forth is interesting. The radiator and remove heat quicker than the engine can produce it while cruising. Cardboard fixed that ;D

[Monster]

Re: Your Thoughts on Hi-Flow Water Pumps

Being Wintertime, I presume you are also running the heater, which also dissipates heat from the coolant.
When a car is overheating during the Summer, I've heard of the heater being turned on with fan on high, lowering the temp 10 degrees.
;)

[CDMBill]

Re: Your Thoughts on Hi-Flow Water Pumps

This to me is a horses for courses conversation. I've run a CSI electric rated at 55 GPH for years now in the 580" BBF. Combined with the Howe two core AL radiator that was in the car when I bought it, and a Mark VIII electric fan has kept the engine in what I see as proper operating temps through 2.2 Drag Weeks, thousands of street miles and lots of drag strip passes not to mention some auto-x and road course work. I do not run a thermostat nor any restrictor plate and I do have steam release, floe balance lines running form the back of the intake manifold into the thermostat housing. I got that idea from Jon Kasse's EMC BBF's.

The flow is similar to an after market mechanical pump running at about 3000 RPM. The CSI always puts out the same amount of flow at all RPM whereas the mechanical increases with speed until it stalls due to restriction, reversion or cavitation. I found it very hard to get flow data for mechanical water pumps, though Edelbrock had some on their web site.

The constant flow is why an electric pump and fan are great for cruises or high traffic low speed issues like clogged freeways. With my particular fan the car will run hotter at steady state freeway speeds with it off unlike many cars as it seems it blocks air flow at high speeds.

So whether you need a high flow pump depends on a lot of other factors. Bottom line the more heat your engine makes the more heat rejection capacity the system has to have and therefore more capacity including high flow pumps ala NASCAR or road racing. Cheapy eBay pumps are a perfect example of getting what you pay for.

[BangShiftChad]

Re: Your Thoughts on Hi-Flow Water Pumps

My experience with the high volume waterpumps has been good. But, they have all been used on street applications that didn't see high rpm. For example my .060 over 388 stroker motor in my Chevy pickup had one. Since it never saw rpm above 5,800 and very rarely at that, the high volume worked good.

I'm not sure I would use the high volume unit for a car with 4.11s and no overdrive that was going to run on the freeway. I think the water might go through it too fast. Not sure though.

[JeffMcKC]

Re: Your Thoughts on Hi-Flow Water Pumps

A thermostat sets the minumum block temp, the radiator ( air flow, fins per inch, number of cores, over all size) should set the max if everything is set up right

[joe_rocket45]

Re: Your Thoughts on Hi-Flow Water Pumps

I never understood the "water pump too big" or "water flows too fast" scenario.... short of air pockets or cavitation.

The faster the water moves the more heat it should transfer, again, short of cavitation.

[JeffMcKC]

Re: Your Thoughts on Hi-Flow Water Pumps

Makes sense, but that's kind of what I was wondering, too. The thermostat as a bigass restriction? Not just that it closes, but it's a big hunk of crap right in the middle of your inlet.

Its a restricton on the outlet.

I drill 4 holes in mine so it evens out the temp a little more. I believe its all about the time it takes for the temp to get into the water.

[chevy3100]

Re: Your Thoughts on Hi-Flow Water Pumps

I never understood the "water pump too big" or "water flows too fast" scenario.... short of air pockets or cavitation.

The faster the water moves the more heat it should transfer, again, short of cavitation.

ding ding ding - we have a winner!

You are completely correct, the faster the water moves, the more turbulence is created, therefor the better the heat transfer. People who complain that the water doesn't stay in the rad long enough to cool it down either do not understand the principals of thermodynamics & turbulence, or are misusing terms. You WILL get less heat transfer if there is any cavitation however (this can be kept to a minimum by using higher pressure)

When you have a cooling problem with a high flow pump or with the thermostat removed it is due to cavitation or air pockets - it is not due to the higher flow rate (that's just a myth that has been perpetuated for years). I size heat exchangers every day as part of my job and can tell you from experience that higher flow rates (within reason - higher flowrate = higher pressure drop) through any heat exchanger will improve performance (provided that you don't go past velocity limts, etc.)

[TC]

Re: Your Thoughts on Hi-Flow Water Pumps

I never understood the "water pump too big" or "water flows too fast" scenario.... short of air pockets or cavitation.

The faster the water moves the more heat it should transfer, again, short of cavitation.

ding ding ding - we have a winner!

You are completely correct, the faster the water moves, the more turbulence is created, therefor the better the heat transfer. People who complain that the water doesn't stay in the rad long enough to cool it down either do not understand the principals of thermodynamics & turbulence, or are misusing terms. You WILL get less heat transfer if there is any cavitation however (this can be kept to a minimum by using higher pressure)

When you have a cooling problem with a high flow pump or with the thermostat removed it is due to cavitation or air pockets - it is not due to the higher flow rate (that's just a myth that has been perpetuated for years). I size heat exchangers every day as part of my job and can tell you from experience that higher flow rates (within reason - higher flowrate = higher pressure drop) through any heat exchanger will improve performance (provided that you don't go past velocity limts, etc.)

Hate to burst your bubble, but the faster the water moves doesn't make it transfer heat faster.

Think of boiling a pot of water, if you put the pot on the flames for a minute and then take it off the water will be warm, probably enough to where you can still put you hand in it, now if you leave the water on the flames for 10 minutes it will boil and burn you.

Or better yet heat up a big piece of metal, angle it at a 45 degree angle and then poor a glass of water on it, then take the metal and lay it flat with a slight tilt so the water will slowly drain off of it. In which of the two ways I just described will the water be hotter after running off the metal??

I'll give you a hint the slower the water travels the more heat it will pick up.

What it comes down to is the coolant needs ample time in the engine to pull the heat out and it also needs ample time in the radiator to dissipate the heat.