Author Topic: Engine Cooling capacity needed per HP, or similar calculation  (Read 10601 times)

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Offline SteveM

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #15 on: October 03, 2016, 01:45:57 PM »
The engine cooling loop definitely needs to be pressurized.  I'm wondering if the engine loop will benefit from a small-ish reservoir (maybe a couple of gallons) as opposed to plumbing directly from the engine to the heat exchanger.

On the cooling loop side, I have room for a big tank.

Steve.
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Offline SPARKY

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #16 on: October 03, 2016, 04:02:57 PM »
BE sure and use Distilled water---do not leave water in your cooling systems because of electrolysis ---I run zincs also ---less noble metals and all
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Offline awelker

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #17 on: October 03, 2016, 04:26:27 PM »
Steve,

What you're thinking with a small reservoir is pretty much what I have.  My radiator/heat exchanger will hold about 1-1.5 gallons on the engine side and is the highest point of the system.  On my old cooling system I just had a 6lb aluminum propane tank converted as a pressurized reservoir, also held just under 1.5 gallons and at the highest point.  Both worked well to keep the engine full with a little reserve.

This was the old setup with a small upper tank:

IMG_0131 by Andrew Welker, on Flickr

Offline Rex Schimmer

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #18 on: October 03, 2016, 04:46:07 PM »
Steve,
You might also consider using the 77-83 BMW three way thermostat which circulates the engine water through the engine until its rated temp is reached and then it opens and modulates the cool water from the cooling system through the engine. You can find them on E Bay for around $15.

Andrew,
I love the detail on your lakester! BUT (you knew there had to be one!) you should really consider using flared inlets on your injector tubes. The potential air flow increase can be as high as 15% and it is free. I have a great article by Dr. Gordon Blair (British air flow expert) if you would like me to send them to you.

Rex

 
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Offline Seldom Seen Slim

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #19 on: October 03, 2016, 04:56:25 PM »
The plate heat exchanger in our heating system is about 12" x 6" thick and maybe 8" high.  I can't find ratings on it -- but it manages to heat the house and the hot tub - total maybe 100k BTU/hr - without a high duty cycle.  How many BTU/hr from an engine?
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Offline awelker

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #20 on: October 03, 2016, 05:44:15 PM »
1 hp = 2,544 but/hr so the numbers get big quick when you talk per hour

Rex, thanks and you got me. That pic was from 2012 when I ran out of time. If you look close on the earlier pic I posted there are clamp on billet aluminum inlets that I probably put too much time into.  Not sure about the paper you are talking about but I read something with inlet shapes versus drag coefficients. Nice catch.

Andy



Offline ggl205

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #21 on: October 03, 2016, 06:30:59 PM »
Andrew, you have a stunningly beautiful tank. A real work of art. I almost hate to see salt on it.

John

Offline NathanStewart

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #22 on: October 05, 2016, 03:33:26 PM »
Mike,
You should really reconsider using a non pressurized system, especially with a turbo motor. The increased water pressure helps prevent the water from boiling especially around the exhaust port, which can be critical in a turbo engine, especially with 16+:1 compression ratio!

Rex

Even though the "heat out" side of the cooling system may not be pressurized, the block/head itself will be pressurized by the water pump (presuming a real mechanical pump and not some dinky electric aquarium pump).  I have logs showing a steady 20psi of coolant pressure in the block with a totally unpressurized tank.  This is another turbo Toyota six capable of four digit power and the "unpressurized" cooling system has worked fine.
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Offline Ron Gibson

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #23 on: October 05, 2016, 04:55:48 PM »
Not to beat a dead horse but.

I understand about the pump pressure. But some engines could flow differently in the water jacket (flat heads) and cause hot spots. More pressure would raise the boiling temp.

My heads have steam ports above the exhaust valves so evidently steam pockets is a problem.

I guess my question is, if you have a 20 psi pressure system, wouldn't the block pressure before the thermostat then become 40 psi with the manual water pump and raise the boiling point that much more?

Ron
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Offline Ron Gibson

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #24 on: October 05, 2016, 05:10:05 PM »
Rex

How would the BMW thermostat be plumbed? It appears from the pictures that it opens straight through and bypasses to the side. Where or how would the bypass be hooked up?

Ron
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Offline ETM

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #25 on: October 05, 2016, 06:15:13 PM »
Rex

How would the BMW thermostat be plumbed? It appears from the pictures that it opens straight through and bypasses to the side. Where or how would the bypass be hooked up?

Ron

Assuming you are looking at an M10 thermostat.

- Water pump draws from the side port.
- Port with 45 tees anywhere between engine and the inlet side of the radiator.
- Port on the other end draws cool water from the radiator outlet.


Offline SteveM

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Re: Engine Cooling capacity needed per HP, or similar calculation
« Reply #26 on: October 06, 2016, 05:05:37 PM »
I definitely need to do some research so I can understand this BMW setup better....

I love learning new stuff! :-D

Steve.
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