Evans Waterless coolant in V6/V8s?

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Winginitt

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[QUOTE="rv6ejguy, post: 480663

But to say coolant can flow too fast to take in or give up its heat in an engine or rad is simply false and not supported by the physics. Feelings don't make facts.[/QUOTE]

So you are saying that if water is flowing through a heat exchanger tube that has cooler air flowing around it, and it is not satisfactorily dissipating enough heat for the system to function properly......that if I keep the water in the heat exchanger twice as long it will not be cooler when it exits the heat exchanger ? Heat exchange is a result of both time of interaction and area of interaction. If the cooling surface area used is minimal....as in many aircraft installations, the time the water is in contact with that cooling surface may need to be maximized. It's basically a matter of surface area vs time of contact. A builder has to have either more surface area or more time in contact with the existing smaller surface area. In both instances I will have applied twice as much cooling air to the water before it returns to the engine. Now that is considering the flow in the heat exchanger independently from the flow in the engine. In real life they are not independent. It simply cannot be said that the amount of time that it takes water to pass thru a radiator has no effect on the amount of heat that will be removed from the water.

Edit: Had another thought that might put this in a better context.

As long as the contact area of heat transfer has an excess capacity of the heat absorbing medium surrounding it, the speed of the medium (water) is basically inconsequential. If you have marginal or less than sufficient heat transfer ability, the amount of time that heat needs in order to dissipate (generally air) would need to be increased.Since water is a more effective medium for heat transfer than air, it usually has excess capacity and the air side is generally where transferring the heat struggles to keep up.

Anyway, at this point I have given my opinion and explained why it makes sense (to me). Don't want to belabor the thread any further with my opinion (right or wrong), so I'll step back and enjoy what others have to say.
 
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pictsidhe

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Mass flow. Look it up.
Or read my post. It even has a spreadsheet attached that demonstrates what happens using the actual physics involved. At least it did until HBA stripped the graph out. Oh well. You'll have to look at the numbers and use your imagination.

The physics is from a peer reviewed ASME paper by two highly respected scientists in their field, which I trust a whole more than the intuition of members here.
 

mcrae0104

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The physics is from a peer reviewed ASME paper by two highly respected scientists in their field, which I trust a whole more than the intuition of members here.
I can't address your argument because it is unclear which part of Q = M c delta t are you disputing.
 
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pictsidhe

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I'm not disputing that equation. But it is only part of the solution. You have two heat exchangers and three seperate fluids involved in a liquid cooled engine. You have terms for one exchanger and one fluid. Surely that's a clue you may be missing some maths? If you aren't going to read my citation, there's no point in discussing this further.
 
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pictsidhe

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I'm a lousy teacher and people here really don't like being wrong. I think that I should quit trying to explain stuff.
 

mcrae0104

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I'm not disputing that equation. But it is only part of the solution. You have two heat exchangers and three seperate fluids involved in a liquid cooled engine. You have terms for one exchanger and one fluid. Surely that's a clue you may be missing some maths? If you aren't going to read my citation, there's no point in discussing this further.
I did read the citation. Unfortunately the photographs are so fuzzy that I can't make out what the author is saying with the series of equations. I looked for a copy of the book online but there was not one readily available.

Perhaps you could clarify: are you saying is that there is an optimum coolant flow rate, and that if it is increased too much, the heat flow rate goes down?
 

tspear

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Perhaps you could clarify: are you saying is that there is an optimum coolant flow rate, and that if it is increased too much, the heat flow rate goes down?
Yes, that is what he is stating. A while back I knew one old mechanic who said the same thing. To try and make the engine last the whole season (amateur levels) many guys often increased the flow rates from the stock crate engines. The mechanic said most racers increase it too much; and actually reduce cooling. Per this old guy, most people did not realize in most crate engine installs, the limiting factor in the cooling system was not the flow rate; but the radiator size/effectiveness. This is why, he put a larger radiator in my Subaru WRX when they boosted my turbo. I never raced, just liked to drive fast.


Tim
 

TFF

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Most cooling systems have the built in flow rate that needs the thermostat or a dummy in its place to operate correctly. The old redneck pop it out to run cool works great for a 50’s pickup going 30 up a hill. It does not work when the system has to be at functioning capacity 100% of the time. Everything I have messed with has to have the thermostat restriction in it or dummy plate for racing. Opened all the way up and it will overheat. At least down here.
 

rv6ejguy

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Counterpoint. I built and drove road racing cars for 13 years, some with up to 5 times the stock hp, many different cars and engine types for myself and my customers. Ran all with no thermostat, never any overheating issues. Water is really moving at 7500-8500 rpm...

Ran my turbocharged Subaru in my RV6 for 5 years without a 'stat, never overheated in the climb on the hottest days, just took longer to warm up as expected. Last 11 years, have a 'stat back in, cools the same.
 

mm4440

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A function of a thermostat or fixed restriction at the coolant outlet of the engine is to increase the BP of the coolant in the heads due to the pressure increase provided by the water pump. It might make the difference in an engine on the edge of destruction. One of the problems in the original sbc is its siamesed exhaust ports in the middle of the heads. It caused a hot spot and failures. It is not a feature of LS engines. Lesson learned.
 

rv6ejguy

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Engines haven't had thermostats on the outlet of the water pump for decades. If anything was on the edge of destruction, it might have been my 1.7L turbo engines making 360hp which is why I used that example to illustrate the point. I'm sure the engineers who designed it never envisioned this level of hp.
 

mm4440

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The conventional wisdom was the restriction on the coolant outlet from the engine improved cooling by slowing the coolant flow through the radiator. I contend that if it worked it was because it was increasing the BP of coolant at the hot spots in the head by increasing the pressure above the cap pressure by the action of the water pump against that restrictor. I think we agree.
If you are interested in another erroneous conventional wisdom we can talk about taildraggers.
 

rv6ejguy

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The conventional wisdom was the restriction on the coolant outlet from the engine improved cooling by slowing the coolant flow through the radiator. I contend that if it worked it was because it was increasing the BP of coolant at the hot spots in the head by increasing the pressure above the cap pressure by the action of the water pump against that restrictor. I think we agree.
If you are interested in another erroneous conventional wisdom we can talk about taildraggers.
I'm not sure what you're saying here. A restrictor used in place of the thermostat on a modern engine resticts flow at the pump inlet. I don't see how this would increase pressure in the block and heads. Maybe I'm not understanding what you are saying here.
 

mm4440

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The restrictor in the sbc was in the thermostat housing where the coolant exits the engine to the top hose to the radiator. A restriction on the inlet to the water pump would increase the chance of cavitation, a dumb idea. I could relate a story of oil overheating problems during the development of the Bell Airacobra. It has a lesson that occasionally needs to be relearned. In short, Minimize restrictions on the suction side of a pump.
 

pfarber

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pfarber,

I can see how converting mechanical energy to electrical back to mechanical (engine to alternator to electric pump) will never be as efficient as a straight mechanical pump. It also seems like it likely introduces new failure points; e,g, power failure in the alternator now will likely lead to engine failure.
In your statements that electric saves a lot of weight, have you accounted for the extra battery and alternator power requirements?

Also, do you have any data you can point too which shows mechanical pumps driving off the ICE are less reliable than electric pumps?

Tim
The cost to generate 10A at 12v is less than the HP to turn the water pump. Generally you can expect to spend 5-15hp on a water pump.

We'll go for the middle road of 8hp which is 6000watts.

"A typical 12v 60 Amp alternator produces 720 watts at 55% efficiency. It needs just 1310 watts to drive it or a little under two horsepower at 1492 watts MAX". 6000-1500=4500 watts

How much would a certified motor owner pay to get +6 free HP? What is the cost difference between an O-320 150hp vs O-320 160hp?

You actually REDUCE the points of failure.

For a pressurized engine you have the following moving parts:

t-stat
water pump
belt x2
idler (if using a serpentine)
radiator cap
overflow tank
overflow tank cap

Un-pressuized, electric water pump with synthetic coolant has the following moving parts

water pump
radiator cap

Since the altenator, battery, and altenator belts are in common, they are not listed.

How can I remove the t-stat? Simple. Since the water pump is now VARIABLE I can control temp with pump RPM and direct reading of the coolant temps. Even IF this method proves difficult to control temps, I can just add the t-stat back in as STILL have less moving parts to fail.

Didn't think of that, did ya?

As for water pumps failing... well, I'm sure there's an actuarial table somewhere. From what I can tell a pump should have a life of 150000 miles. But electric pumps have a much shorter life of 2000 hours (per one manufacturer). How long will it take to put 2000 hours on the hobbs??






 
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pfarber

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Stock pumps move lots of water at idle. All modern engines are validated for cooling performance from idle to maximum sustained output. Doesn't take much water flow to cool 5-10hp.

I don't think you appreciate the significance of thermal conductivity in coolants. As you can see from the specs I published, Evans has MUCH worse TC than 30/70 EGW. This cannot be easily offset by increasing coolant flow.

You'll have more weight with your plan. I stated the reasons why and you'll still need an expansion/ filling/ venting tank as this stuff expands when heated.

Anyway, I say go ahead and experiment. It can work fine if you get the details right but it won't be lighter and it won't have as low drag as possible running 30/70 EGW with the mechanical pump.
Stock water pumps, at idle, move almost nothing. http://www.ws6.com/mod-14.htm "The stock pump is rated to flow 25 gallons per minute at 6000rpm." Idle at 450 means you are in the low teens. The electric water pump can be adjusted to control temps on the fly.

I don't need any expansion tanks. Once I get to operating temps whatever spills out will be left out. Since I don't need to worry about coolant volume affecting coolant pressures and therefore the boiling point.

The 20% radiator increase is the only unknown at this point. Can I optimize, IN AN AIRCRAFT INSTALLATION the cooling system to negate that additional radiator size. I think it can be done. At 200hp the radiator volume is not that large.. 400cu/in. add 20% to that is moving from a 20x20x1 radiator to a 24x20x1 radiator. Not a significant amount to add.

And on top of that, with good ducting and cowl flaps I think the cooling temps can be handled with the smaller radiator. Why? Because at all times I am moving more cooling mass through the system. And at taxi, this is where the biggest gain needs to be made. If the radiator is a tad small for climb out, I can simply lower the nose.
 

pfarber

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Some people just can't be reasoned with.
How you drive your water pump doesn't change its power consumption by a hundred fold.
https://www.meziere.com/Products/Cooling-System-Products/Pumps-Electric/Chevy/Electric-Pump-Chevy-BB-Standard.aspx
  • Amperage draw: Under normal use the pump will draw 6-7 amps.

7A*12V=84W = .11HP that's the additional load on the engine. For giggles, if you have a 120A 12V alternator the max HP load is STILL ONLY 1440W. Even at 50% efficiency that still less than 3-4HP TOTAL

A water pump can suck +8HP and you STILL need to turn the alternator at +3HP.

That's the math. Please show yours. What are you talking about 100 fold?

So again.. a lighter system, with less moving parts that increases HP. Please explain to me the downsides? The 20% increase in radiator area is a guideline. Even IF the radiator has to be enlarged, 20x20x1 single pass vs 24x20x1... I'm not seeing a huge issue.
 
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