Discussion: Let's talk coolant

JWillis72 · 12-09-2013, 10:25 AM

Quote:

Originally Posted by DEpointfive0

I use water wetter or... The other one (don't remember the name off the top of my head)

Are you running it with water? Do you like it?

DEpointfive0 · 12-09-2013, 10:27 AM

Quote:

Originally Posted by JWillis72

Are you running it with water? Do you like it?

I've run with water, with a 10-20% glycol solution and on 50/50

No complaints, not sure how much cooler I really ran, but for $6-7, why not

chops · 12-09-2013, 11:52 AM

Quote:

Originally Posted by DEpointfive0

I've run with water, with a 10-20% glycol solution and on 50/50

No complaints, not sure how much cooler I really ran, but for $6-7, why not

whats your usual coolant temp range? ive run water wetter for the last few months and CSF radiator. hover around 180 degrees most of the time

DEpointfive0 · 12-09-2013, 01:16 PM

Quote:

Originally Posted by chops

whats your usual coolant temp range? ive run water wetter for the last few months and CSF radiator. hover around 180 degrees most of the time

Well, yeah, I'm around the same because of the thermostat and the only time I drive is early morning and late at night, and Sunny Southern California has turned into the god damn arctic, so at 40 degrees outside, my water temp has been lower that usual

IDZRVIT · 12-09-2013, 01:44 PM

Quote:

Originally Posted by DEpointfive0

Just as an FYI, race cars, use 100% water, MAYBE with additives, but not a 50:50 coolant solution or anything close to it

I don't race cars but I see that water is used because ethyl glycol is not environmentally friendly and would be slippery if leaked on a track from an accident and does not evaporate as quickly as water. Also, water is fine for a race car because it's not in an engine long enough to cause corrosion but will still cool adequately under pressure. So, pure water is not better than 50/50 mix for non-race cars. Use a higher flowing water pump and/or a bigger rad for better cooling.

Words of wisdom: "If it ain't broke, don't fix it."

chops · 12-09-2013, 02:24 PM

Quote:

Originally Posted by DEpointfive0

Well, yeah, I'm around the same because of the thermostat and the only time I drive is early morning and late at night, and Sunny Southern California has turned into the god damn arctic, so at 40 degrees outside, my water temp has been lower that usual

bhaha..its been 20-30 up here in norcal

IDZRVIT · 12-09-2013, 03:31 PM

Quote:

Originally Posted by DEpointfive0

Well, yeah, I'm around the same because of the thermostat and the only time I drive is early morning and late at night, and Sunny Southern California has turned into the god damn arctic, so at 40 degrees outside, my water temp has been lower that usual

Ah, not enjoying the arctic blast we sent down form the GWN?

Mandingo · 12-09-2013, 04:26 PM

What is in the waterless coolant? The structure of a molecule means everything in chemistry. Just bear with me. I live for this stuff and I'm bored at work. *takes a deep breath*

Ethylene glycol looks like this: HO-CH2-CH2-OH. And water looks like this: H-O-H (but with a bend)

Ethylene glycol is obviously the larger molecule. It has a carbon-to-carbon bond and interaction between its two -OH groups which limits bond rotation and vibration. For these reasons, the bonds contained within the ethylene glycol molecule are not as free to vibrate/rotate as the weaker bonds in the smaller H2O molecule.

Temperature is our measure of this molecular "vibration" (also called Brownian motion). So water (a very unique molecule actually) with its bent structure and multiple ways to vibrate and rotate does a better job of "picking up" Brownian motion from the metal in one area and transferring that vibrational kinetic energy to another metal surface (the radiator).

The trade-off of course, is that water has a lower boiling point than ethylene glycol. If you're still reading you are awesome. Ethylene glycol is larger than water and has more potential for intermolecular interaction with nearby ethylene glycol molecules (due to hydrogen bonding and London dispersion forces). This makes it much harder for EG to enter the gas phase since more heat energy would be required to break those bonds/interactions with nearby molecules. Water's intermolecular interactions, while still relatively strong, are not as strong as EG's. Therefore, water is more willing to enter the gas phase with less heat energy imparted to it.

Redglare · 12-09-2013, 04:29 PM

ideally you want to increase the specific heat (c) of the solution to have the best coolant possible, however ethylene glycol has a reduced specific heat, so you want to mix it with water to increase the specific heat.

also have to consider that branching lowers the BP, hence why ethylene glycol is also picked over other alternatives.

also fun fact, even though ethylene glycol doesn't have the double bond between the vicinal OH's, the name retains ethylene because it was derived from an alkene.

TerribleONE · 12-09-2013, 04:48 PM

Subd

IDZRVIT · 12-09-2013, 05:58 PM

Quote:

Originally Posted by Mandingo

What is in the waterless coolant? The structure of a molecule means everything in chemistry. Just bear with me. I live for this stuff and I'm bored at work. *takes a deep breath*

Ethylene glycol looks like this: HO-CH2-CH2-OH. And water looks like this: H-O-H (but with a bend)

Ethylene glycol is obviously the larger molecule. It has a carbon-to-carbon bond and interaction between its two -OH groups which limits bond rotation and vibration. For these reasons, the bonds contained within the ethylene glycol molecule are not as free to vibrate/rotate as the weaker bonds in the smaller H2O molecule.

Temperature is our measure of this molecular "vibration" (also called Brownian motion). So water (a very unique molecule actually) with its bent structure and multiple ways to vibrate and rotate does a better job of "picking up" Brownian motion from the metal in one area and transferring that vibrational kinetic energy to another metal surface (the radiator).

The trade-off of course, is that water has a lower boiling point than ethylene glycol. If you're still reading you are awesome. Ethylene glycol is larger than water and has more potential for intermolecular interaction with nearby ethylene glycol molecules (due to hydrogen bonding and London dispersion forces). This makes it much harder for EG to enter the gas phase since more heat energy would be required to break those bonds/interactions with nearby molecules. Water's intermolecular interactions, while still relatively strong, are not as strong as EG's. Therefore, water is more willing to enter the gas phase with less heat energy imparted to it.

So, at the end of the day, we're concerned about the heat transfer rate of the coolant transferred into the metal radiator and the metal radiator fins transferring its heat into the air flowing across the surface. As long as the radiator can reject the heat of the coolant to the ambient air and keep the outlet temperature from the rad below the boiling point of the coolant, then the engine won't overheat assuming its in perfect order. Steady state, steady flow. That said, why would anyone want to increase the boiling point of the coolant to 375F when it's not necessary? Nice write up, btw.

fzgood · 12-09-2013, 06:02 PM

Quote:

Originally Posted by Mandingo

What is in the waterless coolant? The structure of a molecule means everything in chemistry. Just bear with me. I live for this stuff and I'm bored at work. *takes a deep breath*

Ethylene glycol looks like this: HO-CH2-CH2-OH. And water looks like this: H-O-H (but with a bend)

Ethylene glycol is obviously the larger molecule. It has a carbon-to-carbon bond and interaction between its two -OH groups which limits bond rotation and vibration. For these reasons, the bonds contained within the ethylene glycol molecule are not as free to vibrate/rotate as the weaker bonds in the smaller H2O molecule.

Temperature is our measure of this molecular "vibration" (also called Brownian motion). So water (a very unique molecule actually) with its bent structure and multiple ways to vibrate and rotate does a better job of "picking up" Brownian motion from the metal in one area and transferring that vibrational kinetic energy to another metal surface (the radiator).

The trade-off of course, is that water has a lower boiling point than ethylene glycol. If you're still reading you are awesome. Ethylene glycol is larger than water and has more potential for intermolecular interaction with nearby ethylene glycol molecules (due to hydrogen bonding and London dispersion forces). This makes it much harder for EG to enter the gas phase since more heat energy would be required to break those bonds/interactions with nearby molecules. Water's intermolecular interactions, while still relatively strong, are not as strong as EG's. Therefore, water is more willing to enter the gas phase with less heat energy imparted to it.

Thank you for posting this. Easy to understand for my chemistry-hating brain. Finished reading even though I had my Brownian motion well before the end.

7419sundat · 12-09-2013, 06:32 PM

Water has a better specific heat than Evans waterless coolant thus cooling better but needs needs pressure to increase the boiling point. That stuff is also super thick so it creates more drag on the pump. There's an article on the internet where they tested an ls engine heat, power etc, Evans vs water vs 50/50. They ended up losing power with waterless coolant.

12-09-2013, 04:26 PM	#23 (permalink)
Mandingo Track Member Join Date: Nov 2010 Location: Dallas Posts: 625 Drives: '10 370z 6spd Rep Power: 3371	What is in the waterless coolant? The structure of a molecule means everything in chemistry. Just bear with me. I live for this stuff and I'm bored at work. takes a deep breath Ethylene glycol looks like this: HO-CH2-CH2-OH. And water looks like this: H-O-H (but with a bend) Ethylene glycol is obviously the larger molecule. It has a carbon-to-carbon bond and interaction between its two -OH groups which limits bond rotation and vibration. For these reasons, the bonds contained within the ethylene glycol molecule are not as free to vibrate/rotate as the weaker bonds in the smaller H2O molecule. Temperature is our measure of this molecular "vibration" (also called Brownian motion). So water (a very unique molecule actually) with its bent structure and multiple ways to vibrate and rotate does a better job of "picking up" Brownian motion from the metal in one area and transferring that vibrational kinetic energy to another metal surface (the radiator). The trade-off of course, is that water has a lower boiling point than ethylene glycol. If you're still reading you are awesome. Ethylene glycol is larger than water and has more potential for intermolecular interaction with nearby ethylene glycol molecules (due to hydrogen bonding and London dispersion forces). This makes it much harder for EG to enter the gas phase since more heat energy would be required to break those bonds/interactions with nearby molecules. Water's intermolecular interactions, while still relatively strong, are not as strong as EG's. Therefore, water is more willing to enter the gas phase with less heat energy imparted to it. waaaasabi, gbrettin, Hubbabubba and 3 others like this. __________________ some mods

12-09-2013, 04:29 PM	#24 (permalink)
Redglare Enthusiast Member Join Date: May 2012 Location: FL Posts: 387 Drives: C172 Skyhawk GIII Rep Power: 175	ideally you want to increase the specific heat (c) of the solution to have the best coolant possible, however ethylene glycol has a reduced specific heat, so you want to mix it with water to increase the specific heat. also have to consider that branching lowers the BP, hence why ethylene glycol is also picked over other alternatives. also fun fact, even though ethylene glycol doesn't have the double bond between the vicinal OH's, the name retains ethylene because it was derived from an alkene. Mandingo likes this. Last edited by Redglare; 12-09-2013 at 04:41 PM.

12-09-2013, 04:48 PM	#25 (permalink)
TerribleONE A True Z Fanatic Join Date: Jan 2009 Location: Socal Posts: 10,203 Drives: WOT Rep Power: 5851	Subd __________________ 638WHP 541WTQ @ 13.5PSI Build thread

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12-09-2013, 06:32 PM	#28 (permalink)
7419sundat Base Member Join Date: Aug 2011 Location: colorado Posts: 145 Drives: 09 370z Gtm TT 2 Rep Power: 14	Water has a better specific heat than Evans waterless coolant thus cooling better but needs needs pressure to increase the boiling point. That stuff is also super thick so it creates more drag on the pump. There's an article on the internet where they tested an ls engine heat, power etc, Evans vs water vs 50/50. They ended up losing power with waterless coolant.