evans NPG coolant

[IvoryJ30t]

i came across this during a search.

i dont know if this is a good product, or just gimmickey junk, ive never used it, or anyone i know.

supposedly, its a nonaqueous propylene glycol coolant that is non toxic, has a 375F degree boiling point, and does not require a pressurized cooling system. also, they tout that it never needs replacement.

and it does the laundry and cleans your house.

http://www.evanscooling.com/

what do you guys think of this stuff? worth the time, or just another gimmick?

[DAEDALUS]

1) How good is it transferring heat to and from metals?

2) How much energy does it take to raise the temp (J/g/K)

[IvoryJ30t]

i couldnt find info on its specific heat [calories/gram/degree or joules/grams/kelvin].

the website goes into this primer on thermodynamics, but leaves out all the important information. looks like an attempt to make the product look good by having all this important looking information to sway the average person.

unless i overlooked it, i couldnt find a section where the compare the propylene glycol to water or water/ethylene glycol.

was kinda hoping someone had some first hand experience with it to give it merit, or debunk it.

[IvoryJ30t]

i found the physical properties page.

it has a specific heat of .66 btu/lb/F compared to waters 1.00 btu/lb/F

it also has a thermal conductivity of .114 btu/hr-ft-F they dont say what water's conductivity is on that scale, nor do i know that scale off the top of my head. i think they left water out on that one for a reason.

i dont like it anymore. the fact that they tout that it doesnt boil untill 375 degrees doesnt mean crap to me.

oh wow, my coolant isnt boiling, but my engine's melting...

[IvoryJ30t]

water has a thermal conductivity of almost 4 times the npg coolant. i had to dig up the values for water on that scale.

verdict- its junk.

[BigJuiceSr20]

A lot of rotary guys use Evans coolant. It is not junk. http://www.rx7club.com/showthr...s+npg

[Q45tech]

Not something you want to use in Nissans where ignition advance is a function of coolant temperature, as even if it was [is] more efficient, it would then raise the coolant temperature out of the heads- REDUCING power output.

What happens to some degree with Wetter Water or even pure distilled water it may make the heads cooler by transferring some extra heat to the coolant which then signals ecu to reduce power.

But normally accelerations are short in time [less than 15 seconds] so the coolant nor the sensor responds immediately.

Why making sure your coolant temp sensor is very accurate is important!

Would be interesting to data log the coolant temp RISE in an acceleration run.

In Summer I use 25% AF and distilled water and wetter water, in winter 50/50 AF..............just drain the rad in November [~~4 quarts] and replace with a ~~gallon of 100% AF, the mixture becomes instantly ~~50-55% AF.

[IvoryJ30t]

does that chart apply to all nissans?

my girlfriends 95 max is getting slightly bad mileage [about 20 mpg] even though i just gave it a tune up. the o2 sensors are up for replacement soon [74k] and ive been wanting to check the CTS. probably has to do with the 87 octane she fills it up on.

it doesnt seem like a good idea to use something as a coolant with a significantly lower specific heat than water.

granted, a hotter coolant will dump heat from the radiator more effectively, but at the cost of the engine running hotter. doesnt seem to encourage longevity.

[IvoryJ30t]

hey, maybe evans is good stuff. i just dont like BS marketing tactics like this-

"Evans NPG Coolant will transfer 27.5% more heat energy than water in your race engine, due to NPG's molar heat of vaporization and high saturation temperature."

maybe im a little off on my physics/chemistry, but how would the heat of vaporization have anything to do with a coolant that never boils?

[that is not worded correctly. i mean never boil during the course of standard use, not that it NEVER boils]

im just turned off by there "facts" and marketing.

possibly with a standalone, and tuning, it would run great.

but with a standalone, i would have to tune the motor for water, and then spend weeks to months fine tuning the part throttle parameters, only to have to retune for a higher operating temperature after the switch to evans.

Modified by IvoryJ30t at 3:24 PM 10/19/2004
Modified by IvoryJ30t at 3:25 PM 10/19/2004

[Nismo_Freak]

hey, maybe evans is good stuff. i just dont like BS marketing tactics like this-

"Evans NPG Coolant will transfer 27.5% more heat energy than water in your race engine, due to NPG's molar heat of vaporization and high saturation temperature."

maybe im a little off on my physics/chemistry, but how would the heat of vaporization have anything to do with a coolant that never boils?

The vapor saturation point can dictate the presence of nucleate boiling within the molecules lining the coolant passage walls (which is where the majority of thermal transfer takes place). This takes place as a result of the subcooled fluid being of a varying temp, which absorbs the gaseous bubbling thus creating a quench effect along the walls. So such factors like temp, saturation temp, interfacial heat transfer coefficient, latent heat, vapor void fraction, and down to the number and diameter of the gaseous bubbles. This can dictate small differences in thermodynamic properties under high stress (heat/pressure) situations. It is evident in the small graph below.

You'll find that a large part of the world uses Propylene Glycol based coolant as standard due to the environmental hazards of EG.

http://www.lyondell.com/html/p...shtml

More than you wanted to know about PG.

PG has also been ran in racing for quite a while now... it yeilds greater efficiency in extracting heat from the head. GM has proven this, as has plenty of others like BMW, Porsche, Audi, VW, and a number of other European car manufacturers.

Me and Fred have been researching PG for the past month or so, and if you'd like I can give you some inclination as to what we have found but the links really give you most of the answers.

Graph:



More Links.http://www.lyondell.com/html/p...ation/ ... /p...shtml

Equation Links to Thermal Mathhttp://wins.engr.wisc.edu/teac....html

This is about the boundry of my abilities right now

[Nismo_Freak]

im just turned off by there "facts" and marketing.

No offense but their target market is not exactly Chemical Engineers with their 94 Corolla that they drive to and fro.

[DAEDALUS]

While the average coolant temp in the system stays well below the boiling point, there are locations at which boiling occurs continuously at normal op temps. Nucleate boiling occurs in the water jackets around the combustion chamber. It's small droplets that are vaporized and then washed away immediately, to be condensed in the main flow, where things are cooler. The boiling mechanism "absorbs" far more energy than just coolant heating, and is necessary to maintain the overall system temperature.

[Nismo_Freak]

While the average coolant temp in the system stays well below the boiling point, there are locations at which boiling occurs continuously at normal op temps. Nucleate boiling occurs in the water jackets around the combustion chamber. It's small droplets that are vaporized and then washed away immediately, to be condensed in the main flow, where things are cooler. The boiling mechanism "absorbs" far more energy than just coolant heating, and is necessary to maintain the overall system temperature.

The vapor saturation point can dictate the presence of nucleate boiling within the molecules lining the coolant passage walls (which is where the majority of thermal transfer takes place). This takes place as a result of the subcooled fluid being of a varying temp, which absorbs the gaseous bubbling thus creating a quench effect along the walls. So such factors like temp, saturation temp, interfacial heat transfer coefficient, latent heat, vapor void fraction, and down to the number and diameter of the gaseous bubbles. This can dictate small differences in thermodynamic properties under high stress (heat/pressure) situations. It is evident in the small graph below.

Same thing more or less lol...

[DAEDALUS]

Sorry. Did you revise your post? I don't recall reading that in it when I first read it.

[IvoryJ30t]

No offense but their target market is not exactly Chemical Engineers with their 94 Corolla that they drive to and fro.

?? the only toyota ive ever owned was a 1st gen MR2.

look at me, thinking i knew what i was talking about. i didnt take localized boiling into consideration.

i love the engineering forum, i learn something new everyday.

one thing i dont get, they claim that the motor running warmer DECREASES the engines tendancy to knock, and decreases the engines octane requirement. not that i would be looking for those traits, but how would a warmer engine knock less? wouldnt you be increasing the heat absorbed by the intake charge, increasing the tendancy to knock?

[Nismo_Freak]

?? the only toyota ive ever owned was a 1st gen MR2.

I was providing an example, not aiming it towards anyone (I own a 94 Corolla, and I'm a ChemEng student lol).

Anywho...

one thing i dont get, they claim that the motor running warmer DECREASES the engines tendancy to knock, and decreases the engines octane requirement. not that i would be looking for those traits, but how would a warmer engine knock less? wouldnt you be increasing the heat absorbed by the intake charge, increasing the tendancy to knock?

The engine wouldn't run warmer... more of the heat is transfered out of the head and into the coolant, which is then radiated out of the system. The only warming effect would be after the main coolant passages.

[Nismo_Freak]

Sorry. Did you revise your post? I don't recall reading that in it when I first read it.

Yeah I kept leaving a few things out.