[lust4speed]

Probably a lost cause, but here's my thoughts:

1. Double the pump volume and the water only stays in the radiator half as long -- fine because it will loose the second half of its heat on the next pass in the same amount of time. Figures are not relevant since it is the overall concept. So your pump speed only increases 10% and you loose a little BTU bleed off, doesn't matter because the water is going to come back around 10% faster and accomplish the remaining cooling.

2. So why move the water faster (more volume)? Hot spots in the heads are critical areas that need additional cooling. If the water sits too long it will get hotter and have more chance of turning to steam. Move more water past the hot spots and you have a much better chance of avoiding steam pockets. While additional pressure keeps water from vaporizing, so does moving more water; and together they will probably eliminate problems.

3. Engine only needs so much cooling -- too bad we don't know for sure just how much this amount of cooling will be for all variables. Really no such thing as too much flow. Engine pump is sucking as much water as it is pushing and the restriction will be the holes in the head gasket and other engine restricted areas. Only time you're system is going to puke is steam pockets blowing out coolant, and this is a cooling problem and not a pressure problem.

4. Centrifugal pumps always have a liquid shear point whether it is your water pump or your pool filter. As resistance is increased the pump doesn't stop, the impeller simply spins free without moving additional water. Cut off or limit the siphon side and you will destroy a centrifugal pump.

Only reason I now run a smaller crank pulley and a little larger pump pulley is the fan speed that can be reached at full throttle manual shifts. Figure 6,000 RPM shift with a 8" pulley on bottom and 6.5" pulley on top as many Pontiac's were equipped and your poor water pump is spinning at close to 7,400 RPM at max RPM.

So I support the quoted website in the highest pressure possible for your system is a good thing. I also support their contention that the more water through the engine is also a good thing. Together these items will be the best defense against steam pockets.

[Jack Gifford]

Originally Posted by JSchmitz

After reading your [Pontirag's] last post, I have decided it's pointless to debate this, or anything else, with you.

Same here, especially upon reading that he's "not sure" about a radiator becoming less efficient as the coolant inside it approaches ambient air temperature.

[george kujanski]

As I've stated B4, I compare the flow rate issue of a cooling system with a aluminum heat sink used in electronics. Look at the specs of any finned heat sink versus airflow, and the heat sink temp is lower at higher airflow rates. Air is a fluid and so is water, (water is just more dense), the laws of physics apply similarly not counting secondary effects such as cavitation, etc.

George

[surfnuke9]

George, your example is fine for a single variable system.

In the cooling system, both airflow and water flow are variable, so a direct comparison with a heat sink isnt accurate.

[Pontirag]

Consider that the same cooling system is used for a 326 2bbl and a 389 tri power. then consider that for the same with A/C and the cooling system is the same. I think about the statement/claims advertisers make befor I buy a product. I realise they base thier premise on a very nerrow set of cercumstances. Our cooling systems work over a much broader range of circumstances. Also peple work backwards from buying and installing a larger punp to arrive at the initial problem. IE. they start with the solution and work back to a problem. Thus justifying the solution.The ends justifies the means. And with a salesman filling in the blanks its hard to resist shiny new heavy duty parts. Been there my self. Got the pum to prove it.

Its important to work a problem from its source or begining point to the solution and not the inverse. You will become surprised at some simple and inexpensive remidial or corrective action that resolves the problem. A personal example would be putting a new aluminum performer RPM intake and a 750 Holley on a car to gain HP when the car also needs a basic tune up. Starting at the solution I gained more power. working backward i realised i needed the intake and carb. I was correct and my percieved problem was solved. BUT I needed a tune up as well and it would have gained me more hp as well and would have been cheaper. But I did not address that issue. Same deal with cooling systems.

An example in cooling system troubleshooting. I figured I needed a larger volume pump. All the car mags said so. So I got one , installed it and i kept blowing water out of the radiator cap and the car over heated. After going back and forth with pumps and pulleys ect I realised that two problems were being caused by my new pump. First it was pumping too much water and when it hit the radiator and met resistance, pressure built up and overcame the cap and blew water out. I presumed it was a symptom of over heating.wrong? they water temp was bearly hot.

And guess what the second problem was: after the engine blew out all that water it did begin to overheat. two unrelated problems caused by a solution looking for a problem that origionaly did not exist. Still got the pump,

Two final words: Fluid Dynamics, Not sales marketing. Fluid dynamics.

[JSchmitz]

Originally Posted by surfnuke9

(assuming air flow rate and temperature is constant) It

Originally Posted by surfnuke9

In the cooling system, both airflow and water flow are variable

So, which is it?

Originally Posted by lust4speed

1. Double the pump volume and the water only stays in the radiator half as long -- fine because it will loose the second half of its heat on the next pass in the same amount of time. Figures are not relevant since it is the overall concept. So your pump speed only increases 10% and you loose a little BTU bleed off, doesn't matter because the water is going to come back around 10% faster and accomplish the remaining cooling.

I like your comments. In this example, the water is in the engine a shorter amount of time also. As long as the temp drop in the radiator is a higher percentage (compared to the engine heat exchange) than at the lower flow rate, the total heat disipated is greater.

Originally Posted by lust4speed

While additional pressure keeps water from vaporizing, so does moving more water; and together they will probably eliminate problems.

And more flow through the block increases the pressure in the block. Assuming the restriction stays the same.

Originally Posted by lust4speed

Only reason I now run a smaller crank pulley and a little larger pump pulley is the fan speed that can be reached at full throttle manual shifts. Figure 6,000 RPM shift with a 8" pulley on bottom and 6.5" pulley on top as many Pontiac's were equipped and your poor water pump is spinning at close to 7,400 RPM at max RPM.

That's ok, water pumps are cheaper than engines. Also, I shift at 5200. It spends most of the time spinning 3000rpm or less (3.23:1 gears). When I changed my setup, from non-a/c, to a/c pullies it cooled much better at all speeds. Even though the tips of the vanes were surely aerating the water, and the coolant had no times to cool.

[JSchmitz]

Originally Posted by Pontirag

An example in cooling system troubleshooting. I figured I needed a larger volume pump. All the car mags said so. So I got one , installed it and i kept blowing water out of the radiator cap and the car over heated.

Originally Posted by Pontirag

I got a high volume water pump. it works fine.

??????????????

['ol Pinion head]

Read something to the contrary, early in this thread. Can relate ALL '69-81 Pontiac V8 original GM waterpumps are not the same. The original "296" castings built for 301's & 265's had a low drag cast impeller. The impeller blades in these are shorter.

Have the original "296" waterpump from my '80 Turbo car, it crapped out at 35K miles (I had the alt belt too tight...DUHH). Over the years, I've been buying up & rebuilding original casting & dated '68-74 Pontiac waterpumps. Those are the date range most buyers have wanted. With the high point restoration of W72 T/A's getting more popular, will soon be offering late date "296"s.

[surfnuke9]

JSchmitz,

Nice how you picked pieces from two posts to make it sound like I was flip flopping.

take two sentences out of anyones posts, completely out of context and they can be contradictory.

[JSchmitz]

It sure sounded like you were reversing the variables to support your arguement. I was just joking however. Thus the

[JSchmitz]

'ol Pinion head,

I tried several times to contact you earlier this year. I was going through my '68 "O" 12/10 bolt. I need the GM parts number for the posi spring. Pleeeaase!!!

['ol Pinion head]

Jeff, Will need to ck an Olds Master Parts book. There are at least 3 different S springs, & off the top of my head can't remember which one is same as type "O" Anti-Spin. I've always compared originals & right now only type O ant-Spin I have is buried in big stack of cores.

[Pontirag]

So we're done here.

[Walter Lansing]

FYI
I am not an expert but here is my personal experiance. I had read the Stewert components website before and tried flowing as much water through the radiator but found it to run too hot, I achieved the coolest fluid temps when I put a 5/8 restrictor at the radiator outlet. The car is a 64 tempest, highly modified 455, CSR water pump, aluminum radiator, 2600 CFM electirfan with shroud. So no I am not convienced with the Stewert compnets statement that more flow through the radiator is better.
Walter

[surfnuke9]

apparently Walter, real world experience and an understanding of a multi-variable heat transfer system dont mean anything. You must have been mistaken and simply lucked into reducing your temps by installing a restrictor.....must have been something else that happened coincidentally with your installation of the restrictor that casued the temp drop.....because we have been told that this is not possible.....

[Pontirag]

Yea. One way or another you gotta keep the water in the engine long enough to do its job. Then kool it off. Stuarts statement fails to account for size of radiator and at what temperature is the air flowing through it. Theoretically in a very narrow sense they are right. but to arbitrarrily and subjectively discount GM engineers and say for instance the 4 core a/c radiator is inefficient in montana in winter because its too large for the job when it may also have to do the same job in Yuma in august. And exactly how does a larger volume pump make the rest of the system more efficient? I dont dispute it....yet. Its just that i dont understand the specifics.

What it comes down to is if you call a company that sells hi volume water pumps and tell them you got cooling problems are they going to sell you a recurved distributor or a adjustable vacuum advance. Maybe? maybe they sell you....a hi volume water pump.

[george kujanski]

Why is a comparison to a heat sink not relevant in this case? Sure you have the heat transfer taking place from the engine to the coolant, and then the heat from the coolant to the radiator and then the air, but in each part of the system, a fluid is tranferring heat. The physics of heat transfer is not going to change for the engine-to-coolant, coolant-to-radiator, or radiator-to air. Move the fluid faster, you move more heat.

A while back I posted specs and graphs for a stacked plate heat exchanger showing temp versus airflow and coolant flow. The temp of the fluid was lower when the airflow and/or the coolant flow was increased. Real world data. I can find it and repost if anyone is interested. One can argue that the heat exchanger is an accurate comparison to the automotive radiator and i hold that the same dynamics occur inside the engine.

George

[surfnuke9]

I havent disputed your statements George, I am simply trying to point out that most people who discuss this issue discount the effect of airflow, ambient temperature and engine workload and concentrate solely on water flowrate to prove their point.

In your electronics heat sink example, you have a relatively constant heat source and are talking about varying the airflow. I dont think it is accurate to a cooling system because in a cooling system, the water flowrate from the pump, airflow rate from the fan or the vehicle moving AND the heat source are all variable (assuming you are using a belt driven pump and fan).

Because there are three variables in a cooling system, heat source, air flow and coolant flow, I think the heat sink comparison is an oversimplification. If all you are looking at is one part of the coling system at a time, your heat sink comparison is right on. I completely agree with your statement above "The physics of heat transfer is not going to change for the engine-to-coolant, coolant-to-radiator, or radiator-to air." That is my point. I think those of us agruing against this are getting hung up on making definitive statement that one variable is all that matters, water flow rate.

another issue that may be catching some of us up is semantics.

"The radiator becomes less efficient as the coolant outlet temps. approaches ambient temperature."

No it doesnt. It become less effective.

[george kujanski]

No disagreement, surfnuke. I'm just trying to explain, on a basic level, that heat transfer systems are more EFFECTIVE when the working fluid is moving at a higher rate RATHER than a slower rate. The items I have mentioned have data to back up the statement, rather than a "gut feeling".

George

[JSchmitz]

Originally Posted by Walter Lansing

FYI
I am not an expert but here is my personal experiance. I had read the Stewert components website before and tried flowing as much water through the radiator but found it to run too hot, I achieved the coolest fluid temps when I put a 5/8 restrictor at the radiator outlet. The car is a 64 tempest, highly modified 455, CSR water pump, aluminum radiator, 2600 CFM electirfan with shroud. So no I am not convienced with the Stewert compnets statement that more flow through the radiator is better.
Walter

I also have a '64 GTO with a 455 (not highly modified) and an aluminum radiator. I have a Flowcooler water pump vs. CSR. I have also tried a good factory pump (1970 n.o.s. w/large impeller). I run a shroud and a severe duty fan clutch. This setup works great. My car would not cool with a 2800 cfm (Black Magic) fan. It's one of the components in a multi-variable system you know. I've also ran a heavy duty fan clutch. It's works good. But, the temp will creep up, at idle, in hot weather. I also run a Robert Shaw high flow thermostat. It showed me an improvement over the stock thermostat. No, wait! That must have been coincidence!