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[random-strike]

you both are morons.

next summer take the tstat out of your car and let it idle in your drive way and over heat.

it won't overheat while you're driving down the highway, but it will in stop and go traffic, or idling.

this is basic level automotive tech.

you might get away with it with a alum radiator and some big ass fans... stock shit. no way. bitch will overheat in the summer

[patsmx5]

you both are morons.

next summer take the tstat out of your car and let it idle in your drive way and over heat.

it won't overheat while you're driving down the highway, but it will in stop and go traffic, or idling.

this is basic level automotive tech.

you might get away with it with a alum radiator and some big ass fans... stock shit. no way. bitch will overheat in the summer

I guess thermogoddamnits is not your strong-suit.

[random-strike]

http://www.oldsmobility.com/overheating.htm

the thermostat -  ALWAYS run a thermostat! Removing your thermostat can lead to cooling problems. The general idea behind a thermostat is to warm the cooling system so that the heater core will function properly. The thermostat also works to slow the flow of water so that it has time to transfer heat through the radiator. Removing the thermostat prevents this heat transfer and can lead to overheating. There are two ways to tell if your thermostat is bad: the engine overheats quickly (within 15 minutes of start-up), and if your rubber hose system "thumps" (which means that the water pump is working, however the flow of fluid is stopped by the closed thermostat.) Check your thermostat by placing it in a pan of water on the stove and checking water temperature with a thermometer. If the thermostat does not open at the proper temperature, buy a new one. No matter how new a thermostat is, they can fail at anytime.

you both are morons.

next summer take the tstat out of your car and let it idle in your drive way and over heat.

it won't overheat while you're driving down the highway, but it will in stop and go traffic, or idling.

this is basic level automotive tech.

you might get away with it with a alum radiator and some big ass fans... stock shit. no way. bitch will overheat in the summer

I guess thermogoddamnits is not your strong-suit.

you are wrong. and have no experience

[patsmx5]

What have I said that is wrong? Please, tell me.

EDIT: Nevermind, not gonna argue with Johny. Pointless.

[random-strike]

What have I said that is wrong? Please, tell me.

an engine CAN OVERHEAT without a thermostat, when its hot outside and depending on the radiator. if you have big badass alum radiator it might not, but it still might...

the thermostat needs to open and close for your coolant system to work properly.

one of the function of the the tstat is to allow the coolant enough time in the rad to cool it down.

its really very simple and basic automotive tech... first class maybe?

[random-strike]

http://autorepair.about.com/library/faqs/bl916h.htm

[patsmx5]

Your sources were misinformed. I'm not pulling out my thermo book to write out the formula to prove you're wrong, but I can tell you that the higher the temperature delta across the inlets/outlets, the less efficient it is from a thermodynamic standpoint. Note to those who aren't familiar with thermo: efficient is not the same as effective. There's soooooooo much misinformation online.

[random-strike]

Your sources were misinformed. I'm not pulling out my thermo book to write out the formula to prove you're wrong, but I can tell you that the higher the temperature delta across the inlets/outlets, the less efficient it is from a thermodynamic standpoint. Note to those who aren't familiar with thermo: efficient is not the same as effective. There's soooooooo much misinformation online.

MORON.

take your grandmas car, take out the thermostat, and let it sit in the driveway. unless its 40 degrees outside it will over heat.

you have zero real world experience. does your book say a car engine will not overheat in the summer without a thermostat?

what will it take for you to believe me?

[patsmx5]

So if you're saying fast flowing fluid through a radiator disipates less heat than slow moving (an lol concept on its own)

this made me laugh pretty good. So do johny's post though.

[random-strike]

So if you're saying fast flowing fluid through a radiator disipates less heat than slow moving (an lol concept on its own) then you can argue the reverse... fast flowing fluid through an engine picks up less heat than slow moving fluid.  If this is the case then why do people sometimes swap out water pumps for higher flowing water pumps?  By your logic you really want a slow water pump.  Faster flow = more effective surface area exposure to the fluid = more heat transfer... PERIOD.  It doesn't matter if 1 molecule has 5 seconds of exposure vs 3 seconds.  When you're pumping 2 or 3x the amount of fluid through you're having more contact and thus more heat transfer.  

at least you're asking questions.

no, i'm not saying if its moving faster it "dissipates" less heat. i'm saying almost all cars that are liquid cooled and designs for the thermostat to open and close all the time. they need to close, or at least restrict the flow to allow the water to sit in the radiator long enough to cool off.

if you put a high flow water pump on a stock engine, it won't make a difference, because the tstat will just close and not let fluid out of the radiator until the water in the block is hot enough anyways.

people use high flow pumps because they have big ass radiators that cool much better than stock ones. their problem is that they have badass engines that make a ton of heat, and the water doesn't get out of the engine fast enough, the radiator is good enough to where it can cool the coolant without it having to stay in it.

[Corey]

in my crx i had a topmount with the downpipe touching the rad (it was wrapped though) and i had no fan on the rad and no tstat and i drove around in the summer and the only time the car ever got hot was if i stopped to sit in traffic, which is to be expected with no fan. as soon as i started moving again, even at 10mph the temp would start to drop immediatley. have no tstat will certainly not cause a motor to overheat.

[random-strike]

hey, i'm done trying to convince you, its no big deal.

take a stock car, remove the thermostat, let it idle in the driveway. it might not overheat in the winter, but it will in the summer.

it still might overheat in the winter depending on the car and how shitty the cooling system is.

it would be really easy for you to just do this and see for yourself. you and pat have no real world experience.

if you remove the thermostat the pressure in the system will be reduced and lower the boiling point, might make it overheat too...

like i said, pat has already proved himself a moron in the 383 thread. using thermodynamic concepts out of context... stupid...

[patsmx5]

I admit I forget which small block engines the laws of themodynamics do not apply to.

[Random Hero]

most.

[patsmx5]

experience and thermo knowledge > domestic engine misinformation

[random-strike]

the bottom line is that some cars will overheat without thermostats.

hondas have good cooling systems and the engines are all alum.

take a car with a cooling system that can barely keep it running operating temp under normal conditions and take the tstat out and it will overheat.

basic automotive knowledge, common knowledge to anyone who has any experience working on cars.

[Corey]

so now its some cars not all?

[patsmx5]

I will say some cars will overheat without a thermostat. This is true in some cases where the engine was designed such that the restriction of the thermostat ensured equal coolant flow to each cylinder. Take it out and some cylinders get more flow while others get less. A lot of older domestics are like this.

But it has nothing to do with how fast the coolant is going though the radiator.

[d112crzy]

the bottom line is that some cars will overheat without thermostats.

hondas have good cooling systems and the engines are all alum.

Are we not talking about a fucking Honda?

Either way, I agree that taking out the thermostat is not a good idea. The temperature will vary way too much, which will make tuning a headache.

[random-strike]

complete and utter dumbassness.

how could anyone possibly believe that if the water flowed through a radiator with a fan on it with no restriction, it would be colder then if you let it sit in the radiator twice as long.

its bizarre... i mean honestly are you fucking retarded?

[Passenger]

This thread is 100% facepalm.

[random-strike]

This makes me want to punt puppies and kittens.  Increasing flow (and effective surface area of the fluid and heatsinks/sources per given time) always results in improved heat transfer.  Always!  ALWAYS ALWAYS ALWAYS.

this might be true if was going through the radiator only (and not the engine) at a faster speed, but on the other side of the radiator is a extremely hot engine, its not like its going to go around and around and around in the radiator, its going through ONCE and back into the engine.

high flow water pumps are made for high powered engines, that have a good cooling system all around, the reason for the pump is not to get the water through the radiator faster, its to get it out of the engine faster, this engine would have a radiator that is good enough to keep up.

[patsmx5]

Johny, here's a crude example to get the point across.

You have a radiator, with a fan blowing a certain mass flow rate of air across it.

You have water entering the radiator at 200*F

If you pump water at 5 gallons/ minute, it may exit at say 150*F

Where if I double the water flow rate to 10 gallons / minute it may exit at 168*F.

Or if I pump 20 gallons / minute, it may exit at 175*F

Guess which one removed more heat in one minute?

[HiProfile]

You guys want some real info on this? I can contact some of the professionals I know regarding heat x-fer of gasses and liquids. Their educations range from England to USA to Australia and even Japan. Or I can sum up their knowledge.

Fact: increasing flow increases heat transfer. Period.

Why? First, faster moving liquids and gasses have a smaller/thinner boundry layer. The boundry layer is the thin area between the surface and the liquid/air that doesn't want to move, and therefor not transfer heat. Reduce the boundy layer, and heat transfer raises by near-expotential amounts. The irregular coolant passages also lend to adding turbulance, which can reduce the boundy layer by a lot. If you want to experiment, wet your fingers and quicly put out a burning match with them. You wont' get burned [not badly, anyways ). The water emulates a boundry layer; it reduces heat transfer, and even insulates when it phase changes to steam.

Slower moving water may allow that small volume of water to cool down more, but it will remove less BTU's over time. While that slow water is cooling down more, the water near the heat source is heating up more. But since the boundry layer is now thicker, less heat is transfered to the coolant. Your water coming out of the radiator may be a bit cooler, but both the coolant going in AND the heat source are much hotter.


Now here's the kink in the system which only applies if you compare regular coolant systems to automotive coolant systems. Most non-auto closed systems have a pump that is cooled by the coolant itself. That's when you can get too big of a pump - it can become the main heat source if your original heat source isn't too big. I've done work on coolant setups where 3/10th of a degree can make or break a setup. The coolant itself only gets a few degrees above ambient, but the item to be cooled gets near 200F. It's a mixture of very concentrated heat, and very high flow rates for the BTU's dealt with.

[patsmx5]

^^^ What he said.

[HiProfile]

Johny, here's a crude example to get the point across.

You have a radiator, with a fan blowing a certain mass flow rate of air across it.

You have water entering the radiator at 200*F

If you pump water at 5 gallons/ minute, it may exit at say 150*F

Where if I double the water flow rate to 10 gallons / minute it may exit at 168*F.

Or if I pump 20 gallons / minute, it may exit at 175*F

Guess which one removed more heat in one minute?

Good example.

The 5 gallons had 250 units of heat removed, 50 units per gallon (50*5)
The 10 gallons had 320 units removed, 32 units per gallon (32*10)
The 20 gallons had 500 units removed, 25 units per gallon.

Lower flow would be more efficient per gallon in this case, however, to keep the inlet temp at 200F you'd need your heat source to dump LESS heat into the system - HALF the heat between the 5 and 20 gallon examples.


BTW I almost forgot, I used to be involved with dirt racing a Pontiac 400 engine. It had to use basicly all stock stuff, and race for 30-45 mins w/o overheating - damn near impossible with those engines. The biggest changes were when we shrouded/ducted that radiator and fan to a redneck-NASA level, and adding the washer behind the water pump vanes. Many older V8 pumps don't have a fancy machined-in volute like Honda blocks, and it would cavitate. You can't do much to the Honda pump, but you can duct the air to it and use a shroud for the fan. That's my best advice.

Electric water pumps are just for reducing parasitic drag, and are moot if you have an alternator. It draws alternator power, which adds parasitic drag again. They also don't have a great lifespan.

[random-strike]

Johny, here's a crude example to get the point across.

You have a radiator, with a fan blowing a certain mass flow rate of air across it.

You have water entering the radiator at 200*F

If you pump water at 5 gallons/ minute, it may exit at say 150*F

Where if I double the water flow rate to 10 gallons / minute it may exit at 168*F.

Or if I pump 20 gallons / minute, it may exit at 175*F

Guess which one removed more heat in one minute?

this analogy would work if you assume that the radiator works well enough for it to actually cool the coolant. you would be correct, if the radiator and fan could actually do the job.

if the radiator and fan are not efficient enough to cool the water in that short period of time, the water that goes through faster will gain more * in the engine that it loses in the rad.

a motorcycle engine without a tstat would be an easy test for you to do this with. most are already borderline with small radiators and small fans.

[random-strike]

easily proved.

take your grandmas 1985 buick, remove tstat, let idle till it melts.

[patsmx5]

Johny, here's a crude example to get the point across.

You have a radiator, with a fan blowing a certain mass flow rate of air across it.

You have water entering the radiator at 200*F

If you pump water at 5 gallons/ minute, it may exit at say 150*F

Where if I double the water flow rate to 10 gallons / minute it may exit at 168*F.

Or if I pump 20 gallons / minute, it may exit at 175*F

Guess which one removed more heat in one minute?

this analogy would work if you assume that the radiator works well enough for it to actually cool the coolant. you would be correct, if the radiator and fan could actually do the job.

if the radiator and fan are not efficient enough to cool the water in that short period of time, the water that goes through faster will gain more * in the engine that it loses in the rad.

a motorcycle engine without a tstat would be an easy test for you to do this with. most are already borderline with small radiators and small fans.

Good. Now you should know that while I made those numbers up off the top of my head, they are similar to what you would find if you did the test yourself. The reason the radiator works better with higher flow rates is because of the turbulence / disruption of the boundary layer as HiProfile explained.

Another bit of info to answer the question of "why".

When water enters the radiator, that first little inch of heat exchanger, the water is say 200*F and the air flowing by it is say 100*F. There's a big temp difference and it's going to dump a lot of heat in that first inch, say 10*. By the second inch, the water may be 190*F, ambient still 100,so still a big temp difference and it might dump 9*. Then the 3rd inch the water is 181* and ambient 100, it dumps 8 degrees. In the first 3", it's dropped 27* Fast forward to the 10th inch, the water may be at say 120* and ambient is 100, it drops 2* in that inch of the core. This pattern is commonly seen with heat exchangers.

And when you double the flow rate, you just skew the numbers, but that pattern remains the same. Might go to 8* on the first inch, 7* on the next, 6* on the 3rd inch, that's still 21* of heat dropped.  Even though I double the flow rate, the temp of the water exiting doesn't go up by 1/2.

IE 28/28 = 100%
    21/28 = 75%

[HiProfile]

if the radiator and fan are not efficient enough to cool the water in that short period of time, the water that goes through faster will gain more * in the engine that it loses in the rad.

It's assumed you can increase your radiator and fan capacity, but you can't reduce the heat source's heat output.


If it the rad/fan can't remove enough heat for the 20gpm model, it can't remove enough heat for a 5gpm model to keep ECT's at 200F. So you're already fucked. If you put more heat into the coolant than you can move, the heat source rises in temp. If you can't remove more heat from the coolant, the temp rises, and so does the heat source.

Regardless of how well the rad/fan work or how efficient per gallon, you're still able to pull more heat from the engine. That's why you'd then step up to a bigger fan/rad. In this scenerio, it's well proven a half rad that thick CAN remove that much heat, and so can the stock pump, so we're left with an airflow problem.