I was running a Meziere HD WP the entire time I was using the NPG+. No worries or issues.

 

i am running my stock radiator, and am not about to change it...hopefully it lasts a few more years. the 1LE rad works just fine. i would assume that it doesn't flow as well as a rad should to utilize their "water pump trick"

what if i drilled a small hole into the thermostat to promote flow, thus reducing the pressure in the system? all i have ever run is standard 50/50 water/coolant mix. i am sure it isn't rocket science, but i am all ears to the folks that have done this with success.

also won't it take a long time to heat the motor up? i am not too concerned with gas mileage, lmao!!! but still want to be able to heat the motor up within a few minutes at the track if the motor is cold.

tia!

 

Precisely why I went back to a thermostat. It would take WAY too long to get to temp, and I also ran a little too cool when cruising at highway speeds in cold weather.

 

Wouldn't thermally insulating the combustion chamber, be the opposite to using the NPG? IOW, By utilizing as much of the heat of combustion to push against piston crown, and consequently generate more torque, in lieu of heat going into the radiator, more conservative timing would need to be implemented. Whereas, by absorbing more of the heat of combustion into cooling medium, more timing could be utilized. Sorta like comparing aluminum head CR, to that of CR possible with same gas/timing, using steel heads.

I don't understand the hot/cold gauge comparo.

 

Very good thread guys. Very informative. Thanks!!

 

Arnie,

One of the benefits that NPG allows is that you can run the motor warmer. A warmer motor gives you the same benefits of coating the chambers by making the motor more thermally efficient. If you could run the motor at 400 degs (if it would live which is not going to happen) then you would have even better thermal efficiency. That along with the ability to resist detonation is the key to this stuff really.

Bret

 

Thanks, Bret. Then, in addition to ability to run the engine a little hotter, it also does a more efficient job of extracting heat from the chamber walls, thus able to prevent detonation or use more ignition timing. OK.

 

guys, I still don't see it. It's not passing my simple logic little brain.
I know just a little about heat transfer and fluid flow but certainly didn't write the book on it.

I still can't see how the NPG can thermally insulate the combustion chamber, and also removed heat from the cylinder head better, and allow for more resistance to detontion. I see that it is stated that this happens, but I just cannot see the sceince behind it. Remember, this is comparing NPG to 100% water and comparing it to regular 50/50 mix.

And I am open to having my mind changed, that is if I can ever "see the light".

Right now I'm of the school that believes water has the best heat transfer properties and with a good flowing water pump will by far out perform NPG in that department. When the water pump doesn't flow the water fast enough is when the cylinder will make steam pockets. But until that point, just how can NPG remove heat better than water? I don't see it?
And I don't see how a hotter combustion chamber can be less resistant to detonation? I do see how an insulated combustion chamber could make more power but that insulation has to be on the combustion side, not the water passege side. If the water passage is "insulated" from heat transfer, the combustion chamber is going to get HOT!!! and thus all the bad things that go with it.

Maybe people see advantages with NPG because the water pump just is not flowing well enough? Slow flow with 100% water will cause boiling - horrible performance. Slow flow with NPG will delay the boiling and provide less than horrible performance?

I'll leave it at that. I guess I'm playing devils advocate since I have not tried the NPG and am a follower of good ol water.

Anyone actually do drag racing testing? I guess engine dyno testing would be good info too. I've seen the NPG advertising but it only compares itself to 50/50 mix. It never compares itself to 100% water.

thanks, Karl Ellwein

 

Actually more water isin't better. At a point moving water too fast thru the motor will not allow the water to transfer the heat of the motor into the coolant. Faster isin't always better. (I think the limit is about 90 L/min or so but don't quote me on that.) Actually in most circle track racing they slow the pump down to reduce drag on the motor, and the new water pump designs do an even better job of this and cool the motor more effectively.

NPG doesn't insulate the chamber better, it does transfer heat better than water and resist Nucleate Boiling. That's what's causing detonation, isolated hot spots in the head, having one part of the chamber extremely hotter than another part will cause the detonation problems. Thermal Barrier coatings keep heat in the chamber, a higher temp coolant keeps the parts surrounding the chamber closer to to the temps in the combustion chamber so less heat is lost to the coolant, which improves thermal efficency.

I'm not here to change your mind or anyone elses. A 100% water mix is going to have the same problems that any water based coolant will have so the same things will happen. You should really read this site http://www.evanscooling.com/html/tech1.htm also David Vizzards book on short blocks (Pistons, Rods and Crankshafts) has a section in it about Evans NPG with dyno tests and that book was wrote in 1992.

Bret

 

Dang Dang Dang.

I re-read the Evans tech page and it still is comparing conventional coolant to the NPG. It does not compare 100% water.

I have to get that 1982 Vizard book and see what he says.

One thing that I was taught back in school is that higher water flow always results in more heat transfer away from a surface in a closed system. It is a LAW.

Check Stewart components web site tech area for more on this.LINK

Here is a snipet from Stweart components,

quote: 1 BTU is the amount of energy required to raise 1 pound of water 1°F. Of all common liquids water requires the most energy to accomplish this. Therefore water has a specific heat of 1°. An Ethylene Glycol/water mix has a specific heat of .5, meaning it requires only .5 BTUs to raise the temperature of 1 pound Ethylene Glycol/water mix 1° F. Propylene Glycol has a specific heat of only .3.

On a typical engine with a coolant flow rate of 100 GPM and an energy loss through the cooling system of 189.5 HP, water would need to gain only 10° F, Ethylene Glycol/water mix would gain 20° F, and Propylene Glycol would gain 33.3° F.

This equation is complicated by the difference in a vapor point of the 3 coolants. Ethylene Glycol and Propylene Glycol have higher vapor points and thus can absorb heat at higher temperatures. However, even with it's lower vapor point, water still carries more heat per unit than the others. Unquote

Karl

 

The Vizzard section on cooling is pretty good.

Still the problem you see with any H2O based setup is that it keeps the properties of H2O. Lower surface tension, lower boiling point that needs pressure to raise it to operable levels etc.... The big problem is the Nucleate Boiling, if you can get rid of that it will cure detonation. The problem with Nucleate Boiling is that it compounds it self rapidly and only looses the steam pockets once the motor is completely cooled off.

It makes sense that more flow would help but for some reason it doesn't work that way. There have been tests conducted (I tried looking for them in the library of articles we have around here but I couldn't find it) but basically 90 L/min worked out to be the rule. Actually I think Stewart Components was part of that article. I've seen it stated both ways though, faster is better or that there is a limit.

Actually that's the point, NPG can be run hotter and cool the motor more effectively plus you don't have to run it under pressure which helps the life of the parts in the system. The only problem with a hotter motor is that VE can suffer because the air intake charge is heated up, but there is usually a gain in power from the increased thermal efficency and lower friction. If you can cure the intake heat transfer into the air charge than you can get VE back to where it was and see and even higher increase in HP. Combine that with the ability to run a higher compression ratio (static or dynamic) you get a motor that has better BSFC numbers so you can gain HP and fuel consumption.

Karl, H2O might do better in taking heat out of the motor but that's not really the point. You don't gain a ton from that other than a colder motor which will radiate less heat into the intake tract and increase VE. If you can increase the the efficency of the rest of the motor (thermal, friction and fuel) and still isolate the intake tract from the added heat then you can gain VE too and be in a win win situation.

Bret

 

This data source indicates the specific heat of a 50/50 water/ethylene glycol solution, at 200degF is 0.865. Ethylene glycol also has a higher specific gravity, so the mass of the 50/50 solution will increase slightly, further reducing the difference between the pure water and 50/50 EG mix. Its "pure" EG that would reduce the specific heat to approx. 0.50, so that quote is a little misleading.

http://www.engineeringtoolbox.com/24_146.html

 

Karl's right. There is nothing in the thermo equations that take coolant velocity into account. The myth about the water flowing too fast came about through a cooling system design flaw, not through the physical properties of water. If the velocity of the coolant was an issue, it would affect the NPG equally. Pump speed is fixed - you can't change it. So whther or not you belive the velocity myth, it cancels out anyway.

IF you think of heat BTU's as physical objects, like rocks, you can imagine the coolant as a conveyor belt. BTU's are loaded on the conveyor belt in the engine, and unloaded at the radiator. A slow moving conveyor quickly gets loaded to capacity and cannot carry any more BTU's. Double the speed of the conveyor and you double the amount of BTU's you can carry.

Double the WIDTH of the conveyor, and you can carry twice as many BTU's at a given conveyor velocity. In this case, the width of the conveyor is analogous to the specific heat of the coolant. NPG has a specific heat of .3. Pure water has a specific heat of 1.0, which in our conveyor analogy makes it 3 times as wide as the NPG conveyor. This is significant because it means for a given pump speed it can move three times as much heat as the NPG.

The claim that NPG 'insulates' the combustion chamber, thereby increasing thermal efficiency, is pure smoke and mirrors. If you turn that statement around, it really means Evans is admitting that they cannot cool the combustion chamber as efficiently as pure water.

As far as nucleate boiling goes, Evans is putting more spin on that than a politician. Let's assume for a minute that the blurb on the Evans site is true. (You can't assume their statements are true, because they have a vested interest in selling their product and thus anything they say requires independent verification; but let's assume for argument's sake that their blurb is factual.) If you read Evans' own spin, they admit that NPG produces nucleate boiling just like water does. Their claim is that NPG produces smaller bubbles than water, not less bubbles. The smaller bubbles come about because of the lower surface tension of the NPG.

If that is true, and that's the best spin on the subject there is because that info came from Evans' site, then you can get the same effect with a couple of bottles of Water Wetter. Water Wetter achieves lower coolant temps by reducing the surface tension of water. Remember, lower surface tension is what makes NPG effective, according to Evans. Now you have the lower surface tension of NPG combined with the specific heat of water - thus you have a formula more effective than water alone and 3 times more efficient than NPG.

Thus, whether or not NPG is more effective than pure water is moot. By Evans' own logic, water combined with a surface tension reducer (Water Wetter) is superior to NPG.

 

I see what you are saying Randy. And that matches all of what I learned in heat transfer and fluid flow.

As to the nucleate boiling, I think it was mentioned early in the thread that nucleate boiling is the state of the cooling liquid where maximum heat transfer is in effect. And I see that Evans is saying that. Nucleate boiling is what we desire and high flow takes best advantage of that. The point before nucleate boiling if fine too. But the point after nucleate boiling is where steam pockets are formed and heat transfer takes a dive. Used to call that "departure from nucleate boiling".
Just to clear that up.

But since I'm only seeing the points about how water is superior to NPG or NPG mix or EG or EG mix, I'm missing the points as to how NPG+ is better for producing power in an IC engine. Right now, to me it looks like NPG+ simply makes the cylinder head hotter and to me that would make it prone to detonation.

Randy, do you have that Vizard book?

Karl Ellwein

 

Karl,

You're right again. Evans' claim about 'insulating' the cylinder head is just smoke and mirrors, like I said before. They try to claim that their coolant works like the high tech thermal coatings inside a cylinder head, but there's a fatal flaw in their logic.

Thermal coatings work to insulate the inside of the cylinder. NPG works from the outside. How does the fuel/air mix know what the coolant is? Why would it care? Too hot is too hot.

Thermal coatings work like a layer of indestructible styrofoam between the hot metal of the cylinder and the fuel/air mix. They prevent heat jumping from the metal to the fuel/air mix and causing pre-ignition. NPG, because it runs hotter than water, would actually INCREASE the heat transfer from the cylinder metal to the fuel/air mix, causing MORE detonation, not less. The analogy is pouring boiling water into identical metal cups, but one has a layer of styrofoam on the outside. Which cup are you going to pick up?

On the departure from nucleate bioling, when is that most likely to happen? Zooming down the drag strip? Flying around the road course? Hardly. More like when you're sitting in traffic with the engine idling (and thus the water pump barely turning) and no air flowing across the radiator (although electric fans go a long way towards dealing with that). So NPG might be good in a situation where you had a mechanical pump, mechanical fans, and did a lot if idling; but not in a performance situation.