Best coolant to run?

[SteveThe Snakes]

3 hours ago, redrider144 said:

I pissed in your gas tank the other day, and you have yet to report any problems from it.  Piss must be good then.  

But Evans runs at a higher temperature because its specific heat capacity is lower than water / antifreeze.  You can run that in your bike, no thanks.

It depends on where you ride. We run bikes very hard at full throttle up monster hills where 50/50 comes a running out. It also comes out on gnarly technical very slow riding. 100% straight antifreeze. 

However if you don’t need it why run it. If 50/50 does the trick there is adequate corrosion protection so all is good.  

[redrider144]

1 hour ago, stevethe said:

It depends on where you ride. We run bikes very hard at full throttle up monster hills where 50/50 comes a running out. It also comes out on gnarly technical very slow riding. 100% straight antifreeze. 

However if you don’t need it why run it. If 50/50 does the trick there is adequate corrosion protection so all is good.  

Did you ever try distilled water with a corrosion inhibitor?  Water has the highest specific heat capacity of any of these fluids.  That means for a given heat input, it will have the lowest temperature increase.  Adding 50% ethylene glycol reduces the specific heat capacity.

A lot of automotive race tracks have banned Evans and other waterless glycols because its flammable.  Of course ethylene glycol would also be offlimits.  That means those guys are running straight water with a corrosion inhibitor.

Edited February 10, 2018 by redrider144

[SteveThe Snakes]

18 minutes ago, redrider144 said:

Did you ever try distilled water with a corrosion inhibitor?  Water has the highest specific heat capacity of any of these fluids.  That means for a given heat input, it will have the lowest temperature increase.  Adding 50% ethylene glycol reduces the specific heat capacity.

Sorry but it boils out and absolutely doesn’t work. Unless you ride easier flowing trails or maybe MX. 

Straight water has a boiling point of 212 degrees slightly more under pressure. 

Straight antifreeze has a boiling point of 387 degrees. It has a freezing point of +5 degrees. 

It will run cooler with less antifreeze but if the riding gets too tough and you loose your coolant your engine is cooked. 

We do this stuff and lots more without overheating. 

 

[redrider144]

4 minutes ago, stevethe said:

Sorry but it boils out and absolutely doesn’t work. Unless you ride easier flowing trails or maybe MX. 

Straight water has a boiling point of 212 degrees slightly more under pressure. 

Straight antifreeze has a boiling point of 387 degrees. It has a freezing point of +5 degrees. 

It will run cooler with less antifreeze but if the riding gets too tough and you loose your coolant your engine is cooked. 

We do this stuff and lots more without overheating. 

 

Straight ethylene glycol also has about 60%of the specific heat capacity of water, which results in 2/3 higher temperature increase for a given heat input.  Not to mention the reduction in flow rate due to higher viscosity.

If I'm having overheating problems , I'm looking at a better water pump, larger radiators, fans etc.  I'm not running 100% glycol.

[SteveThe Snakes]

Just now, redrider144 said:

Straight ethylene glycol also has about 60%of the specific heat capacity of water, which results in 2/3 higher temperature increase for a given heat input.  Not to mention the reduction in flow rate due to higher viscosity.

If I'm having overheating problems , I'm looking at a better water pump, larger radiators, fans etc.  I'm not running 100% glycol.

Um ok don’t. But everyone in our group that does the gnarly stuff does. Been using it for over 20 years ever since CR500’s. Might be well over 20 yrs by now. ?

[Kalamazoo]

On 2/9/2018 at 5:38 PM, EnglertRacing said:

The pure coolant does have a higher boiling point, but the trade off is that the thermal conductivity is lower

What do you mean?

Tons of racing organizations disallow antifreeze

The contaminants will raise the freezing point, so your "sub zero" would be more like 31°. 

[ktm_fastguy]

On 2/9/2018 at 9:00 PM, redrider144 said:

Straight ethylene glycol also has about 60%of the specific heat capacity of water, which results in 2/3 higher temperature increase for a given heat input.  Not to mention the reduction in flow rate due to higher viscosity.

If I'm having overheating problems , I'm looking at a better water pump, larger radiators, fans etc.  I'm not running 100% glycol.

The specific heat is how much heat the fluid will hold.  The energy to get water or coolant boiling hot is very very small compared to the rate of heat being produced by the motor.

The characteristic of the fluid we are looking for is it's ability to transfer heat from and to aluminum buy conduction.  Radiators are heat transfer units.  The tubes and fins are heated by heat transfer from the hot coolant and that heat is transferred to the passing air by convection.  Water is an excellent heat transfer medium but it brings other issues, freezing and corrosion.  Add a little salt to the water and it's an even better for heat transfer but your fluid channels with be choked with aluminum oxide in no time.  

The higher boiling point of pure glycol coolant is not a good factor for choosing the best coolant either.  True it doesn't boil over until its at 375* but you never want your motor to be getting that hot.  Ideally your coolant stays under 200*F.  If it goes out of control other measures are needed.  A fan is the simplest and cheapest.  Bigger radiators is the next step.

Adding water to glycol coolant improves the heat transfer performance of the coolant.  30% coolant is great for cooling but 50:50 is still pretty good for cooling and good for freeze protection.

Premixed coolants based on ethylene glycol are mixed with distilled water.  Evans doesn't use ethylene glycol.  

Race tracks ban ethylene glycol because it's slippery and hard to clean off the track after a crash or boil over. 

Edited February 13, 2018 by ktm_fastguy

[DrKayak]

I think ethylene glycol is nasty crap. I have had it blow back in my face on an overheat, always spill some when changing it then have to clean it up well due to pets will lick it up and die.. 

Started running propylene glycol based coolant in Beta Trials bikes for better corrosion protection with magnesium alloy cases.  I really think propylene glycol is a superior coolant.

http://www.silkolene.com/motorcycle/cooling-system/pro-cool/

If you bike is tuned right and you have a fan I don't see ever reaching temperatures where you need a coolant with 387* boiling point. As stated by others water is better at transferring heat away, straight ethylene glycol is better at holding heat. 

I ran distilled water and water wetter in a KTM 950 and had corrosion issues. Won't do that again. 

[ktm_fastguy]

I too don't care for the poison danger.  The Silkolene looks good.  The label states 50% distilled water.

[redrider144]

51 minutes ago, ktm_fastguy said:

Adding water to glycol coolant improves the heat transfer performance of the coolant

Yes, and do you know why that is?  It's because water has a higher specific heat capacity (1.0) than ethylene glycol (0.56).  So in fact yes, the specific heat capacity of the working fluid is important and relevant.

Edited February 13, 2018 by redrider144

[Yzmaster]

Never had any problems with average 50/50 pre diluted fluid from auto zone ?‍♂️

[ktm_fastguy]

1 hour ago, redrider144 said:

Yes, and do you know why that is?  

The amount of heat your liter of fluid in the bike's cooling system can hold is significant.  But you're leaving out the time factor in the rate of heat transfer.  How fast can the heat be moved into and back out of the fluid.  Water does hold a lot of heat compared to many other fluids.  But also connects well with aluminum to transfer the heat in and get it out on to the radiators quickly.  Additives like Water Wetter improve the ability of water to transfer heat to and from an aluminum surface.  

[redrider144]

1 hour ago, ktm_fastguy said:

The amount of heat your liter of fluid in the bike's cooling system can hold is significant.  But you're leaving out the time factor in the rate of heat transfer.  How fast can the heat be moved into and back out of the fluid.  Water does hold a lot of heat compared to many other fluids.  But also connects well with aluminum to transfer the heat in and get it out on to the radiators quickly.  Additives like Water Wetter improve the ability of water to transfer heat to and from an aluminum surface.  

No, I'm not leaving out time lol.  Aside from having an engineering degree and PE license in Control Systems, classes in thermodynamics, advanced thermodynamics, heat transfer, and fluid mechanics, I have over 20 years in the power industry, 6 as a nuclear reactor operator.  I've been around many many many many many many many heat exchangers, spent thousands of hours analyzing data, including flow rate and heat input changes and subsequent changes in temperature differential across heat exchangers.  Please, just stop.  The specific heat capacity of the working fluid is very much a factor, just as the rate of heat input and flow rates are.  

Edited February 13, 2018 by redrider144

[Jeff aka Bolt]

Run any modern 50/50 premix.  I use Prestone but any equivalent will do.  Water has better heat transfer properties than straight coolant.  I have been riding with a buddy with Evans when he smoked a new motor.  He had an air bubble in the system.  He didn't know the bike was running hot cause Evans does not boil.  So he got a blown $2500 motor for his trouble.

The point of the coolant/antifreeze is that it prevents freezing where needed so you don't crack radiators and engines.  It also brings up the boiling point a bit...  but it doesn't transfer heat as well as straight water.  But water alone boils easier and aids in corrosion.  The 50/50 mix gives you the best of both worlds.

Run an overflow bottle too.  That way if you do get hot you don't spit your coolant on the ground and then suck air back into the system when she cools down.  There is a reason EVERY CAR ON THE PLANET has an overflow bottle.

If available and you ride rough stuff in warm weather slap a fan kit on there.  Good insurance.  Trail Techs fan kit works nicely.  

imho  

Edited February 13, 2018 by Jeff aka Bolt

[jmd426]

Evans.

 

Yes it runs hotter but you also don't get hot spots and air pockets like when boiling with reg coolant. Run a temp gauge try to keep it under 300 and you will be fine and if you do have to stop for a cool down at least you'll still have all your coolant

[shrubitup]

14 minutes ago, jmd426 said:

Evans.

 

Yes it runs hotter but you also don't get hot spots and air pockets like when boiling with reg coolant. Run a temp gauge try to keep it under 300 and you will be fine and if you do have to stop for a cool down at least you'll still have all your coolant

Those who use Evans like it. Those who don't will incessantly mock it. Whatever, be a user. 

[Jeff aka Bolt]

36 minutes ago, shrubitup said:

Those who use Evans like it. Those who don't will incessantly mock it. Whatever, be a user. 

I saw a couple competing opinions...  I missed any mocking.  

[shrubitup]

1 hour ago, Jeff aka Bolt said:

I saw a couple competing opinions...  I missed any mocking.  

Redrider144

[DrKayak]

9 hours ago, Jeff aka Bolt said:

...  He didn't know the bike was running hot cause Evans does not boil.  So he got a blown $2500 motor for his trouble....

Good point that I considered making... My one boil over was due to a blown fan fuse on my 450. It popped the pressure cap, puked, I stopped and figured out the fan deal, replaced fuse and continued the ride. I would rather know it was running way too hot..

[Jeff aka Bolt]

6 minutes ago, DrKayak said:

Good point that I considered making... My one boil over was due to a blown fan fuse on my 450. It popped the pressure cap, puked, I stopped and figured out the fan deal, replaced fuse and continued the ride. I would rather know it was running way too hot..

Yup...  with 50/50 you puke a little coolant and you know you are running hot...  it's not ideal but you have options...  coolant overflow keeps you full unless you really cook it...  take a break and top off with your drinking water...  find a creek...  pee in the radiator...  options.  Over heat with Evans and you silently smoke your motor.  But real world is that you just never know. Maybe you never blow a motor but there is the unknowable loss of motor life... never really knowing why you got 300 hours instead of 600 hours from your last rebuild. 

It's all theoretical...  until it's not.