Coolant addatives

[moto367]

Are all these additives and aftermarket coolants that raise the boiling point really that good for the engine?  Yes, the boiling point of the coolant is increased but are the temps in the motor still there and rising causing damage?

[highmarker]

the additives try to increase heat transfer by eliminating tiny surface bubbles that act as an insulator on metal surface. Picture a pan of water on the stove, bubbles on the bottom. The effect of the additive is short lived in my experience.  Boiling point of coolant is really a function of it's ratio mix with water. More coolant, or all coolant the higher the boiling point,  BUT, the lower the heat transfer from hot metal to cool radiator.  So both boiling point and heat transfer should be considered  by application, neither extreme is automatically better.  If you look at most ALL engine manufactures and antifreeze recommendations it's usually close to 50/50, beenthat way for years.  Not saying you can't run straight water or straight coolant.

[JoeRC51]

My best results have been with Redline Supercool or Redline Water Wetter and water. They're a little better than Engine Ice. The Evans stuff will never boil over , even at motor cooking temps and it's not a good coolant either.

[jaguar57]

if you are talking about antifreeze then it raises the boiling point but reduces actual heat transfer from the cylinder/head. I usually mix 50/50 with distilled water.

[JoeRC51]

19 hours ago, jaguar57 said:

if you are talking about antifreeze then it raises the boiling point but reduces actual heat transfer from the cylinder/head. I usually mix 50/50 with distilled water.

Yes , you're not the only one who knows what antifreeze and/or coolant are for. Redline Water Wetter both raises the boiling point AND increases heat transfer.

[grayracer513]

The plain fact is that no commercially available coolant or coolant/water mix transports heat better than plain water except one, and that's plain water with a surfactant added.  Products like Redline's "Water Wetter" work much the same as soap does to break the surface film tension that exists in water, but without the bubbles.  That allows a better thermal bond between the metal of the engine and radiators and the water.

The unfortunate thing about water is that it boils at only 212 ℉.  Water cools things very well, but once the bubbles start forming, any metal directly at the spot where the water is boiling off of gets no cooling whatever from the steam, and spot temperatures can skyrocket.  Pressurizing the radiator with a pressure limiting cap is one workaround for this, and at sea level, you can get the water to hold off boiling all the way up to 260 ℉ with a 16 pound (1.1 Bar) cap. 

Still, the thing is that whatever metal parts heated the water up to that level as quickly as it happens is obviously much hotter, and water that boils will force its way up out of the system as overflow, leaving the engine with less coolant to do the same job, and that of course, aggravates the situation.  A 50/50 mix of commercial ethylene glycol or propylene glycol coolants and water will raise the boil point to around 280-285 ℉, and gives a little more breathing room.  Higher percentages give more protection against boiling, but cool less well, and allow the engine to run hotter.  When the only temperature warning you have is steam blowing out the tube, things can get undesirably hot.

From a practical standpoint, there is a balance to be struck between keeping the cooler, and keeping coolant in the system.  Recovery systems are fine in the sense that if they work as intended, you can let the bike cool off and it will refill itself, but while it's boiling, it's no better than if it just went on the ground.  That's where specialty coolants like Evans come in. Even though they can't carry off heat as well as plain water, the fact that they basically don't boil until the engine smells of overheated oil means that if nothing else, the cooling system will still be filled and active. For that reason, waterless coolants may be the best approach for extended off-road purposes where the cooling system gets heavily stressed.  I would suggest at least some heat tapes or some other form of temperature monitoring be used along with them, though. 

Consider this too: The purpose of gasoline engine is to extract energy from fuel in the form of heat and convert it to mechanical force.  Some 30% or more of that heat is wasted out the exhaust system, while the cooling system steals another 30%, give or take, depending on the operating coolant temperature.  Running the engine as hot as possible without doing damage to its components is actually more efficient from a power production standpoint. 

[turbo dan]

Corrosion inhibitors are important too.  That's probably the best reason not to run straight water. 

Waterless coolant doesn't boil over, which is nice, but you also don't get any notice when your engine is running dangerously hot.  Ordinarily, with ethylene glycol based coolant, the steam cloud blasting out of the overflow lets you know before you do any harm.  I would rather have notice that I need to let it cool down than have it continue to run until something actually melts down.

In my experience I have had zero issues with a carelessly mixed blend of ordinary automotive coolant and tap water.  Just pour some coolant in, fill the rest with water and go ride.

[JoeRC51]

Hotter is more fuel efficient , not power efficient. Heat prostration waste a lot of power.

[grayracer513]

1 hour ago, JoeRC51 said:

Heat prostration waste a lot of power.

I'm sorry, can you provide an engineering definition of "heat prostration"?

[JoeRC51]

Fatigue , weakness. Does a bike perform better warm or hot ? You don't have to answer the question , I know the answer. The most power is made with cooler water and hot oil.

[87' CR 5003]

Does anyone have experience with Tirox, Ti-cool ? I used to load airplanes, it smells like the de-icer, which I was told mainly bovine urea.

[jaguar57]

cooler water? do we have an option as to what temperature the water runs at? of course not so why even say it

[JoeRC51]

17 hours ago, 87' CR 5003 said:

Does anyone have experience with Tirox, Ti-cool ? I used to load airplanes, it smells like the de-icer, which I was told mainly bovine urea.

I never heard of that one. Redline's description of ''Water Wetter'' still sounds better. 

[JoeRC51]

16 hours ago, jaguar57 said:

cooler water? do we have an option as to what temperature the water runs at? of course not so why even say it

?

[jaguar57]

where can we buy this "cool water". &%$#@! yeah, I want some!

[jaguar57]

actually it's about the reverse of what he said. the engine is kept cooler by the water getting hotter so the more effective the coolant is, the hotter it is. so "cool water" is not the answer but rather Hot water that is hot because it is efficient at absorbing the engine heat

[JoeRC51]

   ?   Glad you  were finally able to read up on it.  ?

[slothspeed]

Some Shifter Kart motor builders would dyno engines stone cold so they could brag about the big numbers. The numbers did not mean much as you cannot race it cold.

[Chuck.]

The cooling systems are designed to run 50/50 coolant/antifreeze; that combo provides freeze protection, corrossion protection, and water pump seal lubrication.  You can increase cooling, but with a slightly lower boiling point, by increasing the percentage of water. Same with surfactants.

Because the goal is heat transfer from the engine to air, a big factor is air flow thru the radiators. Add a fan and the problem is solved. I have two off road bikes with fans and they do a good job of regulating engine temperatures with the result of needing to fuss less with the mixture screw. One has no recovery tank, one has a tank; don't notice much difference in coolant levels.

[grayracer513]

On 5/24/2017 at 5:41 PM, JoeRC51 said:

Fatigue , weakness. Does a bike perform better warm or hot ? You don't have to answer the question , I know the answer. The most power is made with cooler water and hot oil.

"Heat prostration" is a medical term, having nothing to do with metallurgy (fatigue, etc.), which in turn has nothing to do with the efficient conversion of liquid fuel to heat, and heat to mechanical force.  The only thing that will cause an engine to produce more power when it is cooler is the intake air temperature, and that is simply a matter of increasing dynamic compression.  It's a simple reality that the more of the heat of combustion is contained within the combustion chamber and directed as pressure on the piston, the more power is extracted from the combustion process.  An overactive cooling system does nothing more that draw off and waste up to 40% of that heat, and is completely counter productive. 

The exhaust is another loser.  So much wasted energy (roughly another 30-35%) is dumped out the exhaust port that it can be used to drive a turbo charger capable of compressing the intake air beyond two atmospheres in spite of the engine trying to pull air out from in front of it.