quote:

Originally posted by BJs Wild Ride:
Pretty sure the water restricter is about cavitation. Years ago people found that the system would cool better with a restricter. This is because the restricter prevented the pump from cavitation, thus the restricter actually INCREASEd flow rate in that system vs not running one. I was trying to think of an easy way to measure flow rate on the closed system but I haven’t come up with anything reasonable.

I think a restriction is pressure.

I wasn't necessarily thinking of a restriction /pressure, I was thinking turn the water pump off until the radiator is cool to laying your hand on it, from the fan blowing on it.

This is how my transmission cooler works my radiator fan also pulls air through. I just cycle the cool oil into the trans by starting the car for a split second for flow in the trans cooler.

When the engine is running , I think Colorado is 100% correct. In fact when I souped up my sb a couple years ago I had to speed up the Moroso water pump drive to circulate the water faster because I noticed she was running a tad bit warmer than I was accustomed.

It worked like a charm.

I'd be curious to know how much of the total capacity of water in the system on a dragster, is in the radiator. I've got a factory Modine 6 cyliner Nova radiator, I think the systems total capacity is maybe 2 - 2.5 gallons, with one in the radiator. If you have a fan that covers the entire radiator on a dragster, how long could it take to cool the radiator down?

I worked on a 1960's Fury that had a history of overheating hot rodding a 500hp stroked 451 cui engine. I put a $400 Be-Cool fan on it, and you could feel air from the fan blowing out from under the back bumper. And that barge had to be 30 ft long.

This message has been edited. Last edited by: Mike Rietow,

Basic hydraulics:

Pressure is created by RESISTANCE TO FLOW....a restrictor REDUCES flow.....in a closed system, Pascal's law comes into play: When pressure is placed on a confined fluid, there is an equal increase in pressure at all points in the container and at right angles to them....

The cooling system is pressurized....and is uniform throughout the system. When the water pump is turning, it is simply creating flow. The pump DOES NOT create pressure. Only flow. The smaller openings in the head gaskets RESTRICT flow, but do not affect pressure....since it is a closed system under pressure.

Stop thinking the restrictors create pressure, they do not...all they do is limit flow....If you shut off the pump, the heat from the engine is being absorbed into the water, but it's not being cooled since the heat is basically in the same place. There is some radiation, but not much. In the radiator, there is significant radiation (hence the name) due to the construction...if the flow is stopped, the only cooling taking place is in the radiator...if you turn the pump back on to circulate the water, yes, the temp will drop because the cooler water will mix with the hotter water...but only to the point they balance out. The best way to cool is to have continuous coolant circulation into the radiator where the heat is rejected to atmosphere....

Make sense?

I've got a basic hydraulics class to teach tomorrow.....a break from the monotony...

Want a water pump to cavitate? Simple, place too much restriction in the flow path. Water pumps are not very efficient and do not create suction on the intake. Restrict the flow path, when the flow is reduced below the output of the pump, it basically acts like a prop on a boat before the boat moves...lots of beating the water but little motion....the other way is to limit the intake of the pump below what it's designed to move.

What's the total capacity of water in the system vs the amount in the radiator?

Trust me if you restrict water coming out of a water hose with your finger, the phenomenon is more pressure.

But lets forget about that, flow/pressure is not the issue I'm questioning.

I'm questioning the amount of water in the radiator, or more specifically how many times will it have to be cooled to the touch, in order to drop the temp of the engine 40 degrees, and how long will that take?

This message has been edited. Last edited by: Mike Rietow,

quote:

Originally posted by Mike Rietow:

quote:

Originally posted by Coloradoracer:

quote:

Originally posted by Mike Rietow:
Slow down the water circulation through the radiator, so the fan has more time to work on it.

Gotta call you on this one...it's a myth that's been busted about a million years ago....slowing the flow down through the radiator will not cool better, as it allow the coolant in the block to get hotter...best thing is to speed up flow overall. Straight water is best, as it absorbs and rejects heat better than any coolant mixture. It's about taking the heat from one area and transferring it to another....

Better do some more homework on this one Mike, you are wrong.....

I don't mind being wrong, but let me ask ya this before we decide I'm wrong.

What if I was referring to the topic of the thread, turnaround time? Like when the engine is shutdown and Posey is trying to cool it down quickly, in preparation for the next round? Am I still wrong?

Slowing the water down in radiator may allow more heat to transfer out of the water BUT at the same you are moving less cooled water back into the engine. It may be cooler but less of it.

If the fan doesn’t have a shroud that covers the whole radiator that would be the first thing I would change. I was surprised how fast a smaller radiator with full shroud cools my motor compare to bigger radiator and fan with no shroud.

quote:

Originally posted by Mike Rietow:
What's the total capacity of water in the system vs the amount in the radiator?

Trust me if you restrict water coming out of a water hose with your finger, the phenomenon is more pressure.

That's because at that point, the system is open. Without the restriction, there is flow but no pressure...put your thumb over the hose, pressure will build behind it while it restricts flow. But make it a CLOSED system like the cooling system, that doesn't not happen. The pressure is uniform, the restrictor does nothing more than limit flow......

quote:

Originally posted by Mike Rietow:
What's the total capacity of water in the system vs the amount in the radiator?

Trust me if you restrict water coming out of a water hose with your finger, the phenomenon is more pressure.

But lets forget about that, flow/pressure is not the issue I'm questioning.

I'm questioning the amount of water in the radiator, or more specifically how many times will it have to be cooled to the touch, in order to drop the temp of the engine 40 degrees, and how long will that take?

This is where we're at. ???

https://youtu.be/XDbfxaQ4qL8
Check this out while you're contemplating. It's a song I've been listening since I was a kid, wondering if America would ever decline into the MADHOUSE it is today.

quote:

Originally posted by Mike Rietow:
I'm questioning the amount of water in the radiator, or more specifically how many times will it have to be cooled to the touch, in order to drop the temp of the engine 40 degrees, and how long will that take?

It depends on airflow across the radiator. Temp of the air, cfm of airflow, radiator core size, gpm of water flow just to name a few....it's not so simple as to "cool to the touch, in order to drop the temp of the engine 40*"....the cooling rate can be increased by chilling the radiator or by heating the air across it. Both have an effect....one will cool faster, one will cool slower....there isn't one set answer...

You're fishing for an imaginary number Mike.....there isn't one... the amount of water in the radiator won't matter either, it depends on the cooling capacity of the radiator..not water volume...two very different things...cooling capacity is not volume, rather the amount of heat it can reject......

You didn't answer my question. What percentage of the water, of the entire system, is in the radiator? 40%, 50%, 60%?

What is the size of the radiator? How long are the hoses from the engine to the radiator and what sizes are they? How much water does the engine hold????

Answer those questions and you'll have the answer you seek....

quote:

Originally posted by Coloradoracer:
What is the size of the radiator? How long are the hoses from the engine to the radiator and what sizes are they? How much water does the engine hold????

Answer those questions and you'll have the answer you seek....

I'm asking you, I already stated my Nova cooling system capacity.

The majority of water is in the radiator. I don't see a problem cooling it a couple times, cycling the water pump in between. In just a matter of minutes.

That would be my approach to reducing turn around time, most likely.

Slow the water down.

Do what works for you....fastest way is to keep water pump on, fan on, and to spray the radiator down with cold water at the same time.....

quote:

Originally posted by Coloradoracer:
Do what works for you....fastest way is to keep water pump on, fan on, and to spray the radiator down with cold water at the same time.....

The first final round I was ever in at Sunshine, I sprayed water on the radiator to cool it down in a hurry, overheating on gasoline! I'll never do that again! Ever.

Guess why? I'll give ya one hint. Traction.

I always did that, and never an issue....catch is not to drench the radiator, but mist it....the water will evaporate....hose it down and yeah, you'll have issues. I used a four gallon garden sprayer on fan filled with ice water.....worked like a charm but got to be a pain in the butt......

That being said, no more issues for me now! Alky fixed that. I did have to install a tstat to help get temp in it...did a 160*, but after this weekend I'm thinking a 180 will be better.....car seems to like the higher temp....

quote:

Originally posted by Coloradoracer:
I always did that, and never an issue....catch is not to drench the radiator, but mist it....the water will evaporate....hose it down and yeah, you'll have issues. I used a four gallon garden sprayer on fan filled with ice water.....worked like a charm but got to be a pain in the butt......

10 4 roger on that. Hell I'm just kicking around idea's. I agree with more of your idea's, than I disagree.

I do think if you cool the water in the radiator, then cycle it into the engine, it would have to take a pretty big bite out of the engine temp. It does when I cool my trans in this fashion, late rounds. In just a matter of minutes.

A killer fan and shroud as has been mentioned, might be a good place to start for Posey, possibly.

I did the engine and transmission for this dragster, I don't know maybe six years ago. It was having overheating problems or just running a hair warm for their liking.

I think they moved the trans cooler away from the radiator on my suggestion. For the simple reason if you moniter and manage a cool running trans, through a trans temp guage. The engine will follow to a degree. Transmission transmitting less heat into the engine. Common sense right?

So in between rounds they now have a quick way to cool both the engine an transmission.

I've got an old Shogun KoolKan on my digger now. Had it sitting around so put it on. Before my cooler line was looped. After a pass, trans case was too hot to touch....now, case is cool and can is warm...it's working. Don't know if it's the best but it's doing the job for me....

quote:

Originally posted by Coloradoracer:
I've got an old Shogun KoolKan on my digger now. Had it sitting around so put it on. Before my cooler line was looped. After a pass, trans case was too hot to touch....now, case is cool and can is warm...it's working. Don't know if it's the best but it's doing the job for me....

With your engine burning fuel like it is, I'd have a trans temp guage to monitor and manage the trans between 180 to 200 using transmission cooler plus fan similar pictured to meet trans temp management objectives (180-200). You need that heat transmitting from your transmission into your engine. I'd purposely run that trans on the warm side for the engines sake, if it were me.

This is a B&M combo fan and cooler. How these things work is run the fan, when the cooler is cool to the touch start the engine for a split second to move the cool oil from the cooler to the warm transmission, new warm oil to the cooler. Repeat that a couple two three times it'll drop trans temp 20 degrees, in a matter of minutes.