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Water pumps, Flow Cooler vs stock

Twisted Steel Performance

Twisted Steel Performance

Anything worth doing is worth overdoing.
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Just a FYI post, I will be testing the Flow Cooler water pump soon along with a few of the Kennedy Diesel cooling parts. I thought I would show the differences between a stock vs the Flow Cooler unit.

The Flow Cooler impeller is CNC machined and has 10 blades. Also the WP body has been machined and the impeller is thicker than either stock or 130gpm unit.

The stock is cast and has 6 blades. Not shown their is the 130gpm version where the impeller is almost 1/4" wider but still has 6 blades.

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I seriously considered trying the Flow cooler water pump when I had to replace mine last year. I couldn’t find any info from anyone that had used it so I just went back with the balanced flow water pump.

I’ll be following this one too.
 
Well, it looks like I need to slice a couple pumps in half and see for sure, I do know the passages seen in these pics are the same on the 130gpm screw on pump. If I can find a old used screw on pump to slice I'll find out for sure..
 
It has to do with the passages and the 1 port or 2 ports of heater hoses.
If you bench test just the large hose input to the pump and the 2 outlet ports to the block, you will get one reading. Then when you bring in the heater hose port(s) it comes into play.

The balance isnt just a case of volume. Temp of incoming fluid and where it feeds out gets affected too.

The driverside heater hose passage is inlet and flow volume alters based on which thermostat crossover is in use. Single stat with block off, and stat closed, it allows alot of incoming hotter fluid to come in and feeds mostly to the driver’s side. Then of course when the stat is open, it stops flow into the waterpump inlet which now allows a greater amount of cooled water into the driver’s side block while forcing all the heated water to the radiator. This is why many people realized better cooling with the single stat block off style than the dual stat when using spin on waterpump.

The passenger side that is tied into the heater core loop is always ran on a continuous flow valve rather than a simple block off at greater expense to build because they needed it to not disrupt the flow pattern.

The two different restrictors that came factory, again were at an added cost to test, engineering, make, and install them. It wasn’t done for marketing and advertising. No salesman talked about them to potential buyers. So why were they there...

The dual stats were created before the spin on pump, and in primary design had two different temp ranges as an attempt to start the redirection of hetaed coolant earlier. The different supplier of the single was out of the running from the death of owner, so gm stayed with the dual stats even after realizing there wasn’t improvements, and it does cost gm to change back and forth between designs. So even though the single block off did perform slightly better once they used the spin on pump, it wasn’t worth it to go back to the old design.
The talk about 1 vs 2 stat causing elevated pressure and blowing out freeze plugs is total nonsense. A 16 lbs radiator cap blows at 16 lbs- silly right? So even if an IMPELLER waterpump could circulate 5,000 gpm - when the stat(s) are closed and there is no outlet anywhere- the pump still is not a POSITIVE DISPLACEMENT pump. I think some dill-hole had rusty steel plugs that finally let loose when he replaced his pump and blamed it on the new monster pump. He then installs new plugs, and the dual stat and everything holds ok- so he wrongly assumes correlation equals causation and the rest is history. There are too many people (me included) that ran the single stat with better results than the dual stats and somehow we didn’t break the rules of physics and blow our plugs out. Haha. Thats on the polite side. Flat out lie to sell extra parts is another theory...

On the testing- we tried just capping the heater hose ports and couldn’t recreate the same testing problems as in a rig. We saw some of the differences, but not all. You need to flow the water through all passages to see it. That’s why the restrictors existed. And the difference of 2 heater cores came in to play a little also.
When the same mfr that made the heater hose fittings that were restrictive who made the single stat went out and AC Delco started making them, they didnt do the restrictor, wether on purpose or mistake. But I know when I worked in the dealership, they pointed that out- it was listed as a possible contributor of issues and had instructions how to replicate a restrictor and install it. Then we had to wait two extra weeks to get paid that 1.2 / 1.3 or what ever it was because it was billed separately to AC Delco as if it were a defective part waiting credit return.

I appreciate you buying and testing this relatively new pump.
If it has enough volume, it is possible any variation of flow through 1 or 2 heater hose ports has no affect.
On the 1 or 2 ports, a question: do all their pumps have 2 ports and trucks, vans, hummers, etc that only use 1 just plug the other port?
 
@Will L. can you expand on the heater hose restrictor? Say if blocking off the flow completely on the heater hose on a single T stat is bad? What about a wide open nipple that doesn't have a restrictor to replace the POS GM quick connector design?
 
One of the big differences of the spin on pump vs bolt on is the second heater hose port. That changes overall flow through the pumps. Even on the spinon if the port if unrestricted the flow isn’t fully balanced. When it first was done, there was a different manufacturer making the fitting in it that restricted the flow. Iirc the threads are 1” npt but the opening was 10 or 11mm. Later that company went out and the replacement was fully open. That was a part of thr lawsuit between gm and AM General. This is why the restriction fitting is desired, it causes more of the fully hot coolant to go through the radiator, yet allows some flow when tstats are closed instead of in pump cavitation. This is crucial to understand before the difference of crossovers

The single stat with complete block off is good because it forces all fully hot coolant to go through the radiator open and no cavitation when closed.
When using the dual stat crossover same effect.

The difference in flow between the 2 crossovers is so minimal that it creates about 1/15th of a pound pressure change which alters flow volume so low that 100 rpm engine speed has more impact. So either crossover is good as long as if single it needs the blockoff or dual with a restriction between it and waterpump.
Using the dual heater hose waterpump design with the bolt on, it has problems in flow at different locations and time based on that design layout.

As for the factory p.o.s. Quick connect used on various truck engines- that restriction proved irrelevant. We tested cutting flow in half up to doubling it and nothing fixed any of he flow issues until it was a relocation that puts the flow back to the radiator. Blocking off the flow completely made the block and head flow easier to control and less turbulence but returning flow to radiator or lower hose was best.
 
So if I'm understanding all this correctly. If I use a spin on pump with the dual crossover. I need to have a restricted style fitting on the bypass hose that goes between the pump and crossover. Otherwise it won't work to its full potential.
 
@KrisML
Yes.
Leroy sells a really nice one, or diy one.
The originals are all gone.

If diy, you want the restricor at least 1/4” thick and something that is not going to rust. Stainless, brass, etc.

It was funny on the hummer forums, the hummers never got them because of the lawsuit mess, so many folks were and still are reluctant. But once the first 2 guys added them and saw the difference... yeah. Hummers are way worse for overheating issue than pickups. Nothing but proof positive on that forum for them.

The waterpump Chris started here may be the dream part, we just dont know. I called the company about doing flow comparison video demonstrating their product so many of us would be willing to make the jump. They seemed like take it or leave it. And they didn’t know anything about the waterpump alterations gm did over the years or why.

I would really like to see if this new waterpump is good to go, because the hmmwv fanclutch would bolt right up. Best flow with 100% lockup and full control- dream land.
 
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