Can you run the smaller A/C water pump pulley without A/C ?

[Kern Dog]

From my experience, the aluminum 2 core with 1" tubes has the cooling efficiency of a 3 core brass and copper unit.

[A383Wing]

From my experience, the aluminum 2 core with 1" tubes has the cooling efficiency of a 3 core brass and copper unit.

that's what I am running in both my 66's and the Daytona....

Bryan

[c00nhunterjoe]

Question to those who say the ac pulley will overheat a non ac car.
  -How does an ac car not overheat with that pulley setup when the ac is not running? There is no additional heat from the ac condensor unless it is in operation. The difference in crank pulley diameter from non ac to ac grooves is 1/2 total diameter. The water pump rpm difference is negligible.  
   -completely ignoring the 1st question, if the difference in water pump rpm does matter between ac and non ac,  then how does an ac car not overheat when the said ac equipped engine is at 3,000 crankshaft rpm cruising?

I will end with; 98 percent of every overheat problem i have experienced has been airflow, not water flow. 1 percent was waterflow related to a collapsing hose etc, the other 1 percent was too small of a radiator- ie 22" behind a 572 hemi.

[Kern Dog]

The crankshaft pulley diameter is sometimes different between A/C and non A/C applications. That will affect water flow rates.

[c00nhunterjoe]

The crankshaft pulley diameter is sometimes different between A/C and non A/C applications. That will affect water flow rates.

I stated the difference in pulley diameter. 1/2 inch total diameter. Good for max of 100 water pump rpm, 200 if we want to get liberal. so does not explain how an ac car does not overheat as the engine rpm increases.

[John_Kunkel]

Question to those who say the ac pulley will overheat a non ac car.
-How does an ac car not overheat with that pulley setup when the ac is not running? There is no additional heat from the ac condensor unless it is in operation. The difference in crank pulley diameter from non ac to ac grooves is 1/2 total diameter. The water pump rpm difference is negligible.  

It has nothing to do with A/C on or off, it's about using an 8-vane non-A/C pump with A/C pulleys designed to turn a 6-vane pump.. According to the FSM, the combination of pulleys used with A/C provides a 40% overdrive compared to non-A/C pulleys. With non-matched pulley/pump any overheating would be due to cavitation.

With the factory-designed combination of pulleys and pump vanes, the coolant flow stays the same at any given rpm.

[c00nhunterjoe]

Have we seen this tested on a dyno, or just someone that said their car was overheating and a pulley change fixed it. Not doubting the possibility,  just asking for real world proof. Again, pulley changes up and down in size are common practice in the aftermarket performance world. The opposite of the overdrive situation would obviously be underdrive pulleys which are readily available and used frequently without issue.

[cdr]

Like I said early in this thread

"At what rpm does it have cavitation , just asking for a friend" ............ my car has the ac pulleys & none ac pump, if this was a problem it would show up on MY car, 512 cid low deck, A/C, 4k converter, temps down here in Southeast Texas are HOT,,,did I say HOT, OVER 108F,,,, 185ish ALL DAY LONG, sitting in traffic or buzzing 4000 rpm down the Freeway with the A/C on, I call TOTAL BS on this Theory of cavitation , to ad to what Joe said Tuning is also one of the #1 cause of running hot.

[Canadian1968]

I didn't  want to start a battle over the smaller pulley rpm ratio. To me it did not make sense either . So a non AC needs 3500 rpm to turn the pump at the same speed an AC car would turn at 3000.   

With the previous logic the non ac car now has cavitation ?

I know there are many other factors related to over heating . But in didn't think spinning the pump faster would be a big deal.

Side Note. New pump installed , temp gets up to about 190 ish . I flip on the extra electric fans and it actually lowers the temp now, before my dual 10" fans did nothing basically , they now seem to matched a bit better with the added coolant flow !

[John_Kunkel]

I call TOTAL BS on this Theory of cavitation ,

Many years ago a friend installed a clear tube in his water outlet hose and we observed bubbles in the water when using a variety of different restrictors in place of the thermostat. Seen it with my own eyes so I know it's not just a theory.

[A383Wing]

I call TOTAL BS on this Theory of cavitation ,

Many years ago a friend installed a clear tube in his water outlet hose and we observed bubbles in the water when using a variety of different restrictors in place of the thermostat. Seen it with my own eyes so I know it's not just a theory.

also watch a boat propeller under water when it starts to spin fast....seen that myself also

[Paul G]

In industrial pumps cavitation is very destructive. It sounds like rocks bouncing around in the pump, and it erodes away the metal vanes and volute. I can only assume it will do the same in a smaller pump. It can happen when you spin a pump out of it's curve. To slow or too fast.
Below is from this website; https://www.flowcontrolnetwork.com/understanding-avoiding-pump-cavitation/

One of the simplest ways to prevent pump cavitation is to properly operate a pump best suited for the application. In the rental industry, for example, it is common for the end user to lack a working knowledge of pump technology. Instead of running a pump at the ideal rpm for the job at hand, some well-meaning rental customers push pumps too hard to move fluid at faster rates. If a pump works well at 1,800 rpm, the belief is that it will work even better at 2,300 rpm. This is not the case because forcing a pump's performance too far to the right or left of its BEP will result in cavitation over time. If a pump is correctly sized and not starved, the pump will run at the intended speed while maintaining the BEP.

Now I find it hard to beleive that the Chrysler engineers had our water pumps sized so tite they will cavitate if a slightly smaller or larger pulley is used. Pulley size determines pump speed. A pump curve has an operating range the pump can safely operate in. The latest pump technology in industry uses variable speed motor drives (VFD's). The pump will operate at the slowest speed necessary to achieve the required fluid flow. They dont cavitate when kept within the pumps curve.

If our pumps were not capable of running slightly slower or slightly faster I would think Chrysler would be warning about using the correct pump for the size and requirements of the system. They didnt. They did however use the smaller pump as standard, and the larger with A/C when it was needed.

[c00nhunterjoe]

The cavitation is typically because of a restriction. In the case of your clear tube test- the washers as you even said yourself- restrictors. Take flow moving through a 2" pipe and then have it hit a wall and escape through a 1/2" hole.... what do you expect it to do?

   How do we explain the aftermarket pumps that have as many as 15 impeller blades? Ive seen those used with great success as well with my own eyes.

Again, we are talking about a few hundred rpm difference in systems that span several thousand rpm.

[BSB67]

Two Items:

1) The gap between the impeller blades and the corresponding mating surface in the housing body has a lot to do with the amount of water it will flow and its efficiency.

2) The blade area actually looks about the same.  The new one has shallower blades. 

By the looks of those two, I would not bet that the new one will flow more.

[John_Kunkel]

They did however use the smaller pump as standard, and the larger with A/C when it was needed.

Other way around.

[c00nhunterjoe]

What is the rated flow in gpm vs rpm of each pump set up?

[A383Wing]

a long read, but I think there were tests done on each different pump

http://www.dodgecharger.com/forum/index.php/topic,60599.0.html

Bryan

[c00nhunterjoe]

Yup. Starts on page 8. Tests every pump known to big block mopar with a flowmeter.... nothing about cavitation......

[John_Kunkel]

nothing about cavitation......

Didn't read the whole lengthy post, did they have a way to detect cavitation during their tests?

OK, at this point you gotta use your head. Why would the factory (who wants to make a profit) go to the expense of making two different pumps? 

The stated goal of overdriving the water pump was to increase the fan speed for additional cooling on A/C cars. If overdriving the 8-vane pump didn't have any adverse affects, why change to the 6-vane?

[c00nhunterjoe]

nothing about cavitation......

Didn't read the whole lengthy post, did they have a way to detect cavitation during their tests?

OK, at this point you gotta use your head. Why would the factory (who wants to make a profit) go to the expense of making two different pumps? 

The stated goal of overdriving the water pump was to increase the fan speed for additional cooling on A/C cars. If overdriving the 8-vane pump didn't have any adverse affects, why change to the 6-vane?

Page 8, shows the setup with clear tubes and a flowmeter. Cavitation would show. 440 engine was used. Did not overheat in any test.
   Why did the factory change something? Good question. Same could be said about why they never fixed the 727 flow in park issue on a transmission that was used from 1966 thru 2003?

[John_Kunkel]

Apples/oranges comparison. The TF Park issue didn't deal with potential damaging results.

[Paul G]

nothing about cavitation......

The stated goal of overdriving the water pump was to increase the fan speed for additional cooling on A/C cars. If overdriving the 8-vane pump didn't have any adverse affects, why change to the 6-vane?

There you go, that makes sense. With a smaller pulley to speed up the fan they used a lower output pump to keep coolant flow the same as the higher output pump that normally runs at a slower speed.

So what would have been so detrimental about using the higher output pump with the smaller pulley on A/C cars? I would think the flow across the radiator would be greater, although the flow restriction built in to the Tstat is still the same.   

[c00nhunterjoe]

Apples/oranges comparison. The TF Park issue didn't deal with potential damaging results.

You mean like converter drainback overnight that wont recharge in the morning until you shift to neutral and got so bad on the modern trucks with warranty claims that chrysler put bulletins out and installed checkvalves for the converter instead of fixing the valve body so it would charge in park? Yeah thats apples to apples when it cost the company money in warranty work over a simple factory fix.

[John_Kunkel]

So what would have been so detrimental about using the higher output pump with the smaller pulley on A/C cars?

As mentioned from the gitgo, possible cavitation.

[John_Kunkel]

Apples/oranges comparison. The TF Park issue didn't deal with potential damaging results.

You mean like converter drainback overnight that wont recharge in the morning until you shift to neutral and got so bad on the modern trucks with warranty claims that chrysler put bulletins out and installed checkvalves for the converter instead of fixing the valve body so it would charge in park? Yeah thats apples to apples when it cost the company money in warranty work over a simple factory fix.

First off, you're talking about something the factory didn't do (no cost), I'm referring to what they did do (cost money).

Bulletins regarding converter drainback were merely of an advisory nature. And "warranty claims"? Source?

And, you're confused about the purpose of the check valve in later trucks; although it was referred to as a "converter drainback valve", it's purpose was to prevent the high-mounted radiator cooler from draining through the converter. Never had a drain-through problem when the coolers were located in the bottom tank of the radiator. Converter drainback was never eliminated throughout the life of the 727/904 based Torqueflite.