Fred, I have to respectfully disagree with you on a couple of points. While I am using refrigeration as an example. Moving heat is moving heat. If flow exceeds the capacity of whatever you're using for an example, you will not move as much heat.

If flow exceeds design for an evaporator barrel you will not only lose your delta T but you will also see a drop in superheat. Which is in direct relation to the amount of heat you are not putting in to the refrigerant.

On the automotive side, a radiator does have it's limits also. Since everything is dynamic I'm going to assume a couple of constants for the sake of comparison. Let's assume that the btu output of the engine is held at a steady state and that the air flow across the radiator is also held at a steady state. At some point you will surpass the radiators ability to transfer the desired amount of heat.

Same result in the engine. Higher flow equals less time for heat to move from hot surfaces to water, and consequently less time in the radiator tubes to give up the heat that was picked up.

Granted, I'm talking about flow to the point that goes beyond design limits. I do believe that flow can be increased up to that limit and accomplish better cooling. But, I interpreted the discussion to mean that an increase in flow equals better cooling no matter what.

If I'm wrong please re-educate me.

 

True, each water molecule will be able to transfer less heat, but there will be more of them transferring heat each second. If you don't factor in friction heat from the pump, if the coolant was traveling fast enough it would be almost the same temperature leaving the radiator as coming in. That doesn't mean that cooling isn't taking place, though. I try to think of it in terms of "diminishing returns", in other words, making the coolant flow twice as fast may drop the temps by twenty degrees, but twice as fast as that and you'll only lose another ten degrees.

I'm just talking theory here, though, having a waterpump that could actually push that much water would be impractical. A bigger radiator and a higher flowing waterpump that compensates for the added capacity would be the best route.

 

I am using a pump moded by Evens and a 3 core-1" flue rad with Evans coolant, so pluging the bypass would not be the thing for you to do with a stock cooling set up.

 

I absolutely agree with this. If you increase water flow and increase radiator size you will accomplish more cooling. Because, even though less heat is picked up from the engine, the increased delta T across the radiator will give you cooler water entering the engine which would give you a net increase in cooling.

 

Damn-- I always thought the delta was south of New Orleans,where Katrina landed.

Just kidding-- fool with a 'puter or two myself and have 2 water cooled-1 Danger den = 1 Koolance. Had to go back to school on these systems to get 3.8Gh on a P4 3.4 and 4Gh on a Prescott 3.2.
It's not easy with the small units and pumps and rad to do it where it won't hurt the system.



Intel has created a self-contained watercooling unit that will enable the latest Pentium Extreme Edition chips to hit 5GHz with ease.
Unless ya got one of these when it comes out.

Same with a car. The factory system is designed to support what is there when it leaves the factory and little else. Ya can get a little more out of it but ya better have your "poop in a group".

 

855 and N series Cummins are old. I think the 855 has been replaced several times, lol. I dont think Ive ever seen one to tell ya the truth, and Ive worked for Cummins for several years

 

Trucks maybe but not cranes. There are many cranes with 855's.
Ya are just to young to have seen any or not in the profession that uses them.
When ya get into the bigger draglines they have either a Cat 379V8


Or two Cummings,1-855 for swing and either a K19 or a 1710 for lifting.




This is a 4600S5 lift crane 400 ton on its tracks and 600 ton in a ringer.

What I earned my retirement working on for over 40 years.

 

I was just searching for a pic, lol.



Thats where Ive worked on them. Im a generator technition #1, and diesel tech #2. I like to stay as clean as possible, lol.

I still dont think they make them anymore. The government is forcing all those old engines out of work for emissions reasons. We do a lot of repowers on mining equipment.

edit: here is a list of currently manufactured engines http://cummins-sp.com/engines/indust...on_engines.htm from our website.

 

US gov is always trying to spend your tax money.

With cranes or draglines ya rebuild and keep on trucking.
Have repowered some with 855 for swing and "N" series for hoist or 3406 for swing and 3408 for hoist.

Doesn't matter they still have "T" stats and use water.

 

Now that y'all have flexed your DIESEL muscles, can we get back on track.

It doesn't make sense to remove the thermostat cause the engine will take quite a bit longer to get up to temp. How long ? Anyones guess. How long to get to closed loop temperature? See where this is going? I don't think anyone wants to stay in open loop longer than necessary.

Even after all the disagreement of heat transfer or not. Most agree, keep the thermo.

 

Let's think in real world terms. The question has been asked "how much of a restriction is an open t'stat?" The answer to that question dictates the limits of how much the flow through the system is going to change when you remove the t'stat.

I honstly don't know the exact restriction, but if we assume the restriction is on the order of a 20% diameter reduction, you will be adding a small pressure drop to the system. But that single "orifice" is only part of the total flow restriction in the system. If we were to assume that it was the ONLY flow restriction in the system, flow would increase by about 56% when you remove dthe t'stat. But let's asume that the fully opened t'stat represents only 1/2 of the total pressure loss in the system, you realize that the change in flow might only be 25%. Is that increase in velocity enough to virtually eliminate heat transfer at the head and at the radiator?

The answer would be that cooling capacity would be diminished only to the extent that the LMTD decrease exceded the mass rate of flow increase. Yes, LMTD causes diminishing returns, but the flow increase offsets it to a large extent. If you pushed the velocity to ridiculous limits, you would eventually reach the point where LMTD approaches "0" and heat transfer would stop, but that's not the real world problem that we're looking at here.

Note also that we are comparing "stock to stock" here. We're not suggesting a larger radiator, not changing the heat input from combustion. We are discussing whether a stock cooling system will overheat if you remove the t'stat, because the coolant is "moving too fast to pick up (or give up) heat".

This is actually an easy one to prove or disprove.... without all the tech mumbo-jumbo. All we need is someone who has removed their t'stat to tell up if their engine (not their cousin's uncles's girlfriends best friend's engine) has overheated because of this.

Think about it.... everyone willingly accepts the fact that the system without the t'stat will take longer to heat up. But then at some magical point, it is being suggested that heat transfer suddenly disappears and the system overheats.

 

In this entire thread I think there was 1 person that actually said that tunning without one diddnt make his engine overheat. 60 other people debated the physics of it but left no answer.

 

Oh, that can't be true...your's was only the 42nd post.