Whats the Best radiator for extreame heat?
07-12-2007, 09:00 PM
#41
Everything you've said I agree with and I did not mean to imply otherwise.
EDIT: Well I disagree with your statement about water being the most effective coolant. I have heard this before and to my way of thinking (based on my interpretation of "effective"), I disagree. I will try to explain.
There are two problems as I see it: (1) the limited volume of coolant present in our cars (even for water with its high heat capacity) and (2) the low boiling point of water. The specific heat of water is very high, so its capacity to carry heat away from the engine core is great. It can absorb a great deal of thermal energy and the temperature only goes up a few degrees. My argument is that the rate at which it performs this heat transfer is lower than most every other substance on the planet (that comes to my mind anyway). I am basically saying that water is a good insulator of heat. EDIT: This is incorrect - water has high thermal conductivity (at least until it gets too hot).
Think of it another way. If you were to place your hand into a bowl of water at 40 degrees F vs against a copper plate at 40 degrees F, which would reduce the heat in your hand more quickly? Which would feel colder? I would argue the latter.
The glycol solutions are better heat conductors whose temperature will rise more quickly than water (EDIT: this is incorrect; it will rise more because of lower heat capacity, but it will do so more slowly than water due to lower thermal conductivity). A good heat exchanger (radiator/fans) is still a very necessary component, but the temperature differential between ambient and radiator core temperature should rise, further aiding in heat dissipation. I would submit that waters capacity to absorb heat also leads to difficulty in dissipating it (EDIT: this is incorrect). Glycol solutions should help in this regard (EDIT: not exactly, glycol have lower surface tensions and other properties that help prevent formation of a vapor phase layer that can inhibit heat transfer).
Thermal resistance is the concept that I am trying to describe and it was a passing interest in nanofluids that led me to this line of thinking. A recent thread regarding different coolants (and discovering the presence of commercial non-water based products) resparked my interest and hence my posts on the subject. Here is one article from Purdue:
http://www.asee4ilin.org/Conference2005papers/P149.pdf
My background is not in thermodynamics. I am an EE, MD and my field of research is in bioinformatics. So I am way out of my field of study, but I am reading as much as I can. Thanks for the links btw. I am happy to be corrected if I am in error.
For my build Sharif will be putting in Evans NPG+ (much higher boiling point, "nucleate boiling", 0 psi system, no water) for cooling into an otherwise stock setup and I'll be logging and learning.
EDIT: Well I disagree with your statement about water being the most effective coolant. I have heard this before and to my way of thinking (based on my interpretation of "effective"), I disagree. I will try to explain.
There are two problems as I see it: (1) the limited volume of coolant present in our cars (even for water with its high heat capacity) and (2) the low boiling point of water. The specific heat of water is very high, so its capacity to carry heat away from the engine core is great. It can absorb a great deal of thermal energy and the temperature only goes up a few degrees. My argument is that the rate at which it performs this heat transfer is lower than most every other substance on the planet (that comes to my mind anyway). I am basically saying that water is a good insulator of heat. EDIT: This is incorrect - water has high thermal conductivity (at least until it gets too hot).
Think of it another way. If you were to place your hand into a bowl of water at 40 degrees F vs against a copper plate at 40 degrees F, which would reduce the heat in your hand more quickly? Which would feel colder? I would argue the latter.
The glycol solutions are better heat conductors whose temperature will rise more quickly than water (EDIT: this is incorrect; it will rise more because of lower heat capacity, but it will do so more slowly than water due to lower thermal conductivity). A good heat exchanger (radiator/fans) is still a very necessary component, but the temperature differential between ambient and radiator core temperature should rise, further aiding in heat dissipation. I would submit that waters capacity to absorb heat also leads to difficulty in dissipating it (EDIT: this is incorrect). Glycol solutions should help in this regard (EDIT: not exactly, glycol have lower surface tensions and other properties that help prevent formation of a vapor phase layer that can inhibit heat transfer).
Thermal resistance is the concept that I am trying to describe and it was a passing interest in nanofluids that led me to this line of thinking. A recent thread regarding different coolants (and discovering the presence of commercial non-water based products) resparked my interest and hence my posts on the subject. Here is one article from Purdue:
http://www.asee4ilin.org/Conference2005papers/P149.pdf
My background is not in thermodynamics. I am an EE, MD and my field of research is in bioinformatics. So I am way out of my field of study, but I am reading as much as I can. Thanks for the links btw. I am happy to be corrected if I am in error.
For my build Sharif will be putting in Evans NPG+ (much higher boiling point, "nucleate boiling", 0 psi system, no water) for cooling into an otherwise stock setup and I'll be logging and learning.
Last edited by rcdash; 07-14-2007 at 04:07 PM.
07-13-2007, 07:49 PM
#43
Ha ha - that would be Hydrazine and I have great respect for what he has to say! But he hasn't said I'm wrong (not yet anyway!)
There are two factors at play here: heat capacity and thermal resistance. It seems the auto industry has focused on the former and pretty much ignored the latter until recently with the introduction of novel new products.
There is a reason that nuclear power plants are looking to replace water as the coolant of choice with liquid metals such as sodium and mercury...
There are two factors at play here: heat capacity and thermal resistance. It seems the auto industry has focused on the former and pretty much ignored the latter until recently with the introduction of novel new products.
There is a reason that nuclear power plants are looking to replace water as the coolant of choice with liquid metals such as sodium and mercury...
07-13-2007, 09:54 PM
#44
Originally Posted by rcdash
Everything you've said I agree with and I did not mean to imply otherwise.
EDIT: Well I disagree with your statement about water being the most effective coolant. I have heard this before and to my way of thinking (based on my interpretation of "effective"), I disagree. I will try to explain.
There are two problems as I see it: (1) the limited volume of coolant present in our cars (even for water with its high heat capacity)
Yes. So given the limited volume, there is more total heat capasity in a water system than there is in a glycol system.
If pure glycol was used, that same system coolant volume would effectivly be almost half the volume of a pure water system.
And we know more coolant is always better than less coolant.
and (2) the low boiling point of water.
Boiling point is not relavent to a normal operating system because the system is under pressure, and as such, the boiling point is never reached. To reach the boiling point, there must first be significantly abnormal operating conditions.
The specific heat of water is very high, so its capacity to carry heat away from the engine core is great.
Exactly. This is the reason why it is the best coolant.
It can absorb a great deal of thermal energy and the temperature only goes up a few degrees.
Yes, but keep in mind that coolant delta T is not the objective. Transfering heat is the objective.
If coolant Delta T was the objective we could simply reduce the water pump flow rate by 60% and the Delta T would increase alot, but the engine will run hotter... This is not what we want.
The objective is to achieve heat transfer, not coolant delta T.
My argument is that the rate at which it performs this heat transfer is lower than most every other substance on the planet (that comes to my mind anyway). I am basically saying that water is a good insulator of heat.
Water is actually highly thermally conductive, and much more so than glycol.
Think of it another way. If you were to place your hand into a bowl of water at 40 degrees F vs against a copper plate at 40 degrees F, which would reduce the heat in your hand more quickly? Which would feel colder? I would argue the latter.
Yes, assuming the water is absolutely still, the Copper will conduct (transfer) heat faster and "feel" colder. But the comparison is water and glycol not Copper. Glycol OTOH is far more viscous and far less conductive.
See the following link for comparative thermal properties:
http://www.hukseflux.com/thermal%20conductivity/thermal.htm
http://www.lsbu.ac.uk/water/anmlies.html
Although Glycerol is not Ethylene Glycol, they are both glycols and are very similar in structure, density, viscosity, polarity and just about everything else.
The glycol solutions are better heat conductors whose temperature will rise more quickly than water.
If the temperature rises faster with the same heat input, it is by definition a less effective coolant. It is the difference in temperature between the engine and coolant that motivates the heat transfer. (this is basic physics)
If the temperature of the coolant and engine are the same, transfer will not occur. Energy flows down hill (entropy).
If a coolants temperature more rapidly approaches the temperature of the engine, the coolants heat transfer ability more rapidly diminishes.
A good heat exchanger (radiator/fans) is still a very necessary component, but the temperature differential between ambient and radiator core temperature should rise, further aiding in heat dissipation. I would submit that waters capacity to absorb heat also leads to difficulty in dissipating it. Glycol solutions should help in this regard.
If this was how thermodynamics worked we could simply put a restrictor orifice in the coolant pump to achieve a higher coolant temperature and a higher temperature at the radiator.. but the total heat transfer out of the engine will only decrease and the engine will run hotter for it.
Thermal resistance is the concept that I am trying to describe and it was a passing interest in nanofluids that led me to this line of thinking. A recent thread regarding different coolants (and discovering the presence of commercial non-water based products) resparked my interest and hence my posts on the subject. Here is one article from Purdue:
http://www.asee4ilin.org/Conference2005papers/P149.pdf
I like it! Very interesting article. ...But I can't find a connection to the comparison of heat transfer between glycol and water.
And the conclusion actually supports part of what I am saying here.
Nano particles are being used to increase the heat transfer rate by decreasing the thermal boundary layer. And I agree this is absolutely true.
The boundary layer thickness of water will be much, much less at a given flow velocity than glycol. Glycol is viscous like maple surup and will naturaly have a much thicker boundary layer.
For liquids, thermal resistance/conductance is roughly proportional to the reynolds number. So transfer will be higher with water.
My background is not in thermodynamics. I am an EE, MD and my field of research is in bioinformatics. So I am way out of my field of study, but I am reading as much as I can. Thanks for the links btw. I am happy to be corrected if I am in error.
For my build Sharif will be putting in Evans NPG+ (much higher boiling point, "nucleate boiling", 0 psi system, no water) for cooling into an otherwise stock setup and I'll be logging and learning.
EDIT: Well I disagree with your statement about water being the most effective coolant. I have heard this before and to my way of thinking (based on my interpretation of "effective"), I disagree. I will try to explain.
There are two problems as I see it: (1) the limited volume of coolant present in our cars (even for water with its high heat capacity)
Yes. So given the limited volume, there is more total heat capasity in a water system than there is in a glycol system.
If pure glycol was used, that same system coolant volume would effectivly be almost half the volume of a pure water system.
And we know more coolant is always better than less coolant.
and (2) the low boiling point of water.
Boiling point is not relavent to a normal operating system because the system is under pressure, and as such, the boiling point is never reached. To reach the boiling point, there must first be significantly abnormal operating conditions.
The specific heat of water is very high, so its capacity to carry heat away from the engine core is great.
Exactly. This is the reason why it is the best coolant.
It can absorb a great deal of thermal energy and the temperature only goes up a few degrees.
Yes, but keep in mind that coolant delta T is not the objective. Transfering heat is the objective.
If coolant Delta T was the objective we could simply reduce the water pump flow rate by 60% and the Delta T would increase alot, but the engine will run hotter... This is not what we want.
The objective is to achieve heat transfer, not coolant delta T.
My argument is that the rate at which it performs this heat transfer is lower than most every other substance on the planet (that comes to my mind anyway). I am basically saying that water is a good insulator of heat.
Water is actually highly thermally conductive, and much more so than glycol.
Think of it another way. If you were to place your hand into a bowl of water at 40 degrees F vs against a copper plate at 40 degrees F, which would reduce the heat in your hand more quickly? Which would feel colder? I would argue the latter.
Yes, assuming the water is absolutely still, the Copper will conduct (transfer) heat faster and "feel" colder. But the comparison is water and glycol not Copper. Glycol OTOH is far more viscous and far less conductive.
See the following link for comparative thermal properties:
http://www.hukseflux.com/thermal%20conductivity/thermal.htm
http://www.lsbu.ac.uk/water/anmlies.html
Although Glycerol is not Ethylene Glycol, they are both glycols and are very similar in structure, density, viscosity, polarity and just about everything else.
The glycol solutions are better heat conductors whose temperature will rise more quickly than water.
If the temperature rises faster with the same heat input, it is by definition a less effective coolant. It is the difference in temperature between the engine and coolant that motivates the heat transfer. (this is basic physics)
If the temperature of the coolant and engine are the same, transfer will not occur. Energy flows down hill (entropy).
If a coolants temperature more rapidly approaches the temperature of the engine, the coolants heat transfer ability more rapidly diminishes.
A good heat exchanger (radiator/fans) is still a very necessary component, but the temperature differential between ambient and radiator core temperature should rise, further aiding in heat dissipation. I would submit that waters capacity to absorb heat also leads to difficulty in dissipating it. Glycol solutions should help in this regard.
If this was how thermodynamics worked we could simply put a restrictor orifice in the coolant pump to achieve a higher coolant temperature and a higher temperature at the radiator.. but the total heat transfer out of the engine will only decrease and the engine will run hotter for it.
Thermal resistance is the concept that I am trying to describe and it was a passing interest in nanofluids that led me to this line of thinking. A recent thread regarding different coolants (and discovering the presence of commercial non-water based products) resparked my interest and hence my posts on the subject. Here is one article from Purdue:
http://www.asee4ilin.org/Conference2005papers/P149.pdf
I like it! Very interesting article. ...But I can't find a connection to the comparison of heat transfer between glycol and water.
And the conclusion actually supports part of what I am saying here.
Nano particles are being used to increase the heat transfer rate by decreasing the thermal boundary layer. And I agree this is absolutely true.
The boundary layer thickness of water will be much, much less at a given flow velocity than glycol. Glycol is viscous like maple surup and will naturaly have a much thicker boundary layer.
For liquids, thermal resistance/conductance is roughly proportional to the reynolds number. So transfer will be higher with water.
My background is not in thermodynamics. I am an EE, MD and my field of research is in bioinformatics. So I am way out of my field of study, but I am reading as much as I can. Thanks for the links btw. I am happy to be corrected if I am in error.
For my build Sharif will be putting in Evans NPG+ (much higher boiling point, "nucleate boiling", 0 psi system, no water) for cooling into an otherwise stock setup and I'll be logging and learning.
And consider that water can also be used above 212'F (if under pressure) and still have a higher thermal capasity for the same volume of liquid... and lower thermal "resistance" to boot.
Yes, nucleate boiling is by far the most effective way of removing heat. But water can transition to nucleate boiling too, it just does it at a lower temperature and pressure.
When a fluid is in contact with a hot surface there are three phases of thermal transfer. Pre-boiling (a conductive/convective transfer), nucleate boiling and film boiling. Heat transfer continually increases as surface temperature increases. Once nucleate boiling starts, the heat transfer rate jumps up due to the boiling effect carrying away heat in the gas phase and redistributing it away from the surface and into the liquid.
If the surface temperature continues to increase, the liquid will boil more and more rapidly. It will eventually come to a point where it boils so fast that a thin gas phase layer forms between the liquid and hot surface. When this occurs the heat transfer rate surpasses a peak and begins to decrease again. This is film boiling.
But this condition will happen with either water or glycol. Just at different temperatures and pressure.
In any case, liquid water will always have a higher transfer capasity than glycol.
Like you said, all this theoretical discussion means nothing compared to test data. If you are hooking up a data logger with thermocouples on the heads, do a pre/post test under similar conditions with both water and NPG+.
I'm sure you will log a higher head temperature with the glycol.
Last edited by Hydrazine; 07-13-2007 at 10:25 PM.
07-13-2007, 10:02 PM
#45
Originally Posted by rcdash
There is a reason that nuclear power plants are looking to replace water as the coolant of choice with liquid metals such as sodium and mercury...
And liquid metals are among the very few substances that have a higher capasity than water.
They also do not contain hydrogen. At very high temperautures, the hydrogen in water can come free as either the gas or as ions.
Hydrogen causes metal embrittlement to the system plumbing. And metal embritlement to high temperature / high pressure plumbing is a highly undesirable feature to nuclear reactors.
More importantly, glycols will never ever be a consideration for nuclear reactors! Ever!
Last edited by Hydrazine; 07-13-2007 at 10:30 PM.
07-14-2007, 08:43 AM
#46
BTW, I was thinking of that article you linked. Enhancing the transfer properties of water with nano particles of copper oxide.
This would be a test worth trying. It would be very easy to electrolytically produce submicron copper oxide in solution. I don't really know if it will reach the nanoparticle size, but I'll see what can be produced in the lab.
This would be a test worth trying. It would be very easy to electrolytically produce submicron copper oxide in solution. I don't really know if it will reach the nanoparticle size, but I'll see what can be produced in the lab.
07-14-2007, 02:00 PM
#47
It's not the heat transfer capacity that's concerning to me because the volume is too limited for the capacity to be an issue - the difference is not an order of magnitude anyway. We rely on the radiator to maintain a steady state that is within reasonable operating conditions. The specific heat capacity for water and propylene glycol are not so different that we are not reliant on a heat exchanger of the same basic design, correct?
However I was incorrect in assuming an inverse relationship between the specific heat capacity of a substance and it's thermal conductivity. They are two entirely different material properties and I was in error for confusing them.
specific heat of water is high, thermal conductivity = 0.6
specific heat of copper is low, thermal conductivity = 300+
specific heat of propylene glycol is half water, thermal conductivity = 0.3 (? closest value I could find for a 50/50 mix)
I have an e-mail in to the Evans folks to see what the measured thermal conductivity is for NPG+. I have asked them how they compensate for the reduced conductivity (presumed) of their coolant. They do add proprietary additives, but I don't know what they will be willing to disclose. I will post what I find.
Thanks for the links - made this much easier for me to understand where I was making an incorrect leap in logic. I was too eagerly hoping for some of the same nanofluid properties from glycol!
EDIT: I would love to know the results of your "nanofluid" testing. Be careful of unwanted precipitate formation though... don't want you to damage your car based on my lame brain ideas!
However I was incorrect in assuming an inverse relationship between the specific heat capacity of a substance and it's thermal conductivity. They are two entirely different material properties and I was in error for confusing them.
specific heat of water is high, thermal conductivity = 0.6
specific heat of copper is low, thermal conductivity = 300+
specific heat of propylene glycol is half water, thermal conductivity = 0.3 (? closest value I could find for a 50/50 mix)
I have an e-mail in to the Evans folks to see what the measured thermal conductivity is for NPG+. I have asked them how they compensate for the reduced conductivity (presumed) of their coolant. They do add proprietary additives, but I don't know what they will be willing to disclose. I will post what I find.
Thanks for the links - made this much easier for me to understand where I was making an incorrect leap in logic. I was too eagerly hoping for some of the same nanofluid properties from glycol!
EDIT: I would love to know the results of your "nanofluid" testing.
Be careful of unwanted precipitate formation though... don't want you to damage your car based on my lame brain ideas!
Last edited by rcdash; 07-14-2007 at 03:52 PM.
07-14-2007, 04:25 PM
#48
Originally Posted by Hydrazine
When this occurs the heat transfer rate surpasses a peak and begins to decrease again. This is film boiling.
But this condition will happen with either water or glycol. Just at different temperatures and pressure.
But this condition will happen with either water or glycol. Just at different temperatures and pressure.
The Evans NPG coolant has a boiling point of 369[degrees]F in normal atmosphere. "The coolant reaches the nucleate boiling stage, then maintains that state indefinitely -- therefore, it never film boils,"
07-14-2007, 05:54 PM
#49
Evans Cooling should know better than to say something like
All liquids can transition to film boiling.
Heat capasity, conductivity and viscosity are unfavorable compared to water. So far, the only advantage I can find to the NPG is its vapor pressure profile and possibly the surface tension.
If for example the coolant system pressure is limited to 0 pressure, the water will transition to film boiling before the NPG. But we don't have to be fixed on pressure.
One objective for either coolant is to stay away from film boiling. Heat transfer is destroyed by film boiling. And certaintly both can be made to transition into or out of film boiling. Its pressure dependant.
There is one misleading detail about their marketing ad that bugs me though.
When they say
They are referencing the superior MOLAR values for heat capasity and vaporization here. But MOLAR values are totally useless in a cooling system. Using MOLAR values to compare against water (in this situation) is deceptive.
Of course a "MOL" of glycol will have a higher heat capasity than water. Propylene glycol, Ethylene glycol and Glycerine are large, heavy molecules. Water is relatively tiny.
MOLAR values should be used for chemistry, not heat transfer in a cooling system.
In the case of a cooling system, the best value to use is volumetric (with gravimetric as a distant second).
Why should anybody (or even a chemical engineer for that matter) care about the "MOLAR" value in his motor coolant system? WTF? Its not like we are titrating our radiators... It bugs me when I see symantical games being played for marketing.
But hey, put the stuff in and see what it does. If your test data shows it works, I'll put it in my car.
"then maintains that state indefinitely -- therefore, it never film boils."
Heat capasity, conductivity and viscosity are unfavorable compared to water. So far, the only advantage I can find to the NPG is its vapor pressure profile and possibly the surface tension.
If for example the coolant system pressure is limited to 0 pressure, the water will transition to film boiling before the NPG. But we don't have to be fixed on pressure.
One objective for either coolant is to stay away from film boiling. Heat transfer is destroyed by film boiling. And certaintly both can be made to transition into or out of film boiling. Its pressure dependant.
There is one misleading detail about their marketing ad that bugs me though.
When they say
The nonaqueous coolant's properties are significantly different from those of other coolants or additives in popular use today, said Pressley. For example, its boiling point far exceeds a water-based coolant's vaporization or boiling points, so Evans NPG coolant never boils over, even under the most demanding conditions. It boasts a higher molar heat of vaporization and condenses any vaporized coolant sooner and within the coolant jackets, allowing it to absorb even more heat as it circulates on its way to the radiator.
Of course a "MOL" of glycol will have a higher heat capasity than water. Propylene glycol, Ethylene glycol and Glycerine are large, heavy molecules. Water is relatively tiny.
MOLAR values should be used for chemistry, not heat transfer in a cooling system.
In the case of a cooling system, the best value to use is volumetric (with gravimetric as a distant second).
Why should anybody (or even a chemical engineer for that matter) care about the "MOLAR" value in his motor coolant system? WTF? Its not like we are titrating our radiators... It bugs me when I see symantical games being played for marketing.
But hey, put the stuff in and see what it does. If your test data shows it works, I'll put it in my car.
Last edited by Hydrazine; 07-14-2007 at 06:22 PM.
07-14-2007, 08:23 PM
#50
The true value of the NPG+ (according to their marketing) is that it does not film boil, though they do contradict themselves and state that the small amount that does, because of its high boiling point and its low surface tension, immediately returns to the liquid state and thus cooling effectiveness in such high temperatures is not impeded in the way that a water based solution is. More uniform heat management (even if overall temps are higher) minimize danger to the engine. That's the theory...
But what metric can I use to test this claim? I can think of none. The coolant temp will be higher. The core temp will be higher. But the risk of damage due to film boiling should be less - if you believe what they claim... They claim the risk of detonation will be less.
But what metric can I use to test this claim? I can think of none. The coolant temp will be higher. The core temp will be higher. But the risk of damage due to film boiling should be less - if you believe what they claim... They claim the risk of detonation will be less.
Last edited by rcdash; 07-14-2007 at 08:37 PM.
07-14-2007, 10:38 PM
#52
Originally Posted by rcdash
The true value of the NPG+ (according to their marketing) is that it does not film boil, though they do contradict themselves and state that the small amount that does, because of its high boiling point and its low surface tension, immediately returns to the liquid state and thus cooling effectiveness in such high temperatures is not impeded in the way that a water based solution is. More uniform heat management (even if overall temps are higher) minimize danger to the engine. That's the theory...
But what metric can I use to test this claim? I can think of none. The coolant temp will be higher. The core temp will be higher. But the risk of damage due to film boiling should be less - if you believe what they claim... They claim the risk of detonation will be less.
But what metric can I use to test this claim? I can think of none. The coolant temp will be higher. The core temp will be higher. But the risk of damage due to film boiling should be less - if you believe what they claim... They claim the risk of detonation will be less.
1) Thermocouple on the heads. Directly measure the head temperature.
The coolant to produce the lowest average head temp wins.
and/or
2) Dyno tune your car with water and dyno tune your car on NPG...
Which ever can tune for the highest power wins.
That should do it.
07-14-2007, 10:40 PM
#53
Originally Posted by USN HM 350Z
wow, I have a head ache after reading all this
Sheesh. I remember when working at the Boeing rocket propulsion labs. It was a colaboration of the worlds most hard core geeks, techs, Engineers, brains, PhD's and Scientists all battling eachother in the physical sciences.
We did this kind of stuff all day long with real analysis, test reports and with exponential intensity.
Most of the time it was fun.
Last edited by Hydrazine; 07-14-2007 at 10:53 PM.
07-15-2007, 05:19 AM
#55
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I'm surprised no one has suggested dideuterium oxide as a substitute for diprotium oxide as its boiling point is 101.42C.
For those that only the best is good enough, the cost would be ~~$5000 to fill the cooling system.
http://www.fas.org/nuke/intro/nuke/heavy.htm
For those that only the best is good enough, the cost would be ~~$5000 to fill the cooling system.
http://www.fas.org/nuke/intro/nuke/heavy.htm
Last edited by Q45tech; 07-15-2007 at 05:23 AM.
07-15-2007, 12:33 PM
#57
Originally Posted by Hydrazine
I can think of two ways to test.
1) Thermocouple on the heads. Directly measure the head temperature.
The coolant to produce the lowest average head temp wins.
and/or
2) Dyno tune your car with water and dyno tune your car on NPG...
Which ever can tune for the highest power wins.
That should do it.
1) Thermocouple on the heads. Directly measure the head temperature.
The coolant to produce the lowest average head temp wins.
and/or
2) Dyno tune your car with water and dyno tune your car on NPG...
Which ever can tune for the highest power wins.
That should do it.
Your #2 sounds like the best overall way to judge effectiveness - that'd be a PITA for Sharif. I'll leave that up to him. Even if he's not up to doing a controlled study, my sense is that he's got a pretty good idea of where detonation starts on these cars (what timing, what a/f, etc). We'll see if tuning from the get go on Evans NPG+ has an impact on the power levels he feels comfortable with.
EDIT: Maybe I can convince Evans to sponsor a controlled tuning session first with water and then with Evans NPG+. I think Sharif would be willing...
Last edited by rcdash; 07-15-2007 at 07:34 PM.
07-15-2007, 04:56 PM
#58
If they are saying the average head temp will go up, I wouldn't be too sure of its effectiveness.
I also doubt our engine will have these high termal gradients they are referring to. Its not like our cylinder walls are bored out untill they are super thin. (commonly seen in a true race engine) There is probably enough thickness of steel in our stock engine to spread out sharp thermal gradients.
I'm thinking there is a possibility you may even see a decrease of performance with it.
If this stuff only helps when film boiling occurs, what if we never reach that point in the first place.... Now the whole engine is guaranteed to be running hotter for no good reason at all.
But we may never know unless Sharif wants to burn some time or if Evans is confident enough to prove their product to this market...
EDIT: I just thought of something else... It is possible to see an increase in HP simply because a hotter block means hotter oil... Hotter oil means lower viscosity and lower friction losses. I've seen the effect of warm Vs hot oil on the dyno. It makes a a difference.
Take this into account when doing any comparative test.
I also doubt our engine will have these high termal gradients they are referring to. Its not like our cylinder walls are bored out untill they are super thin. (commonly seen in a true race engine) There is probably enough thickness of steel in our stock engine to spread out sharp thermal gradients.
I'm thinking there is a possibility you may even see a decrease of performance with it.
If this stuff only helps when film boiling occurs, what if we never reach that point in the first place.... Now the whole engine is guaranteed to be running hotter for no good reason at all.
But we may never know unless Sharif wants to burn some time or if Evans is confident enough to prove their product to this market...
EDIT: I just thought of something else... It is possible to see an increase in HP simply because a hotter block means hotter oil... Hotter oil means lower viscosity and lower friction losses. I've seen the effect of warm Vs hot oil on the dyno. It makes a a difference.
Take this into account when doing any comparative test.
Last edited by Hydrazine; 07-15-2007 at 05:15 PM.
07-15-2007, 07:38 PM
#59
Evans e-mail system said it may be a week for a response - I'll post whatever they say...
We should try to control for temperature to minimize variability due to temperature related factors - maybe not running fans with water+water wetter to maintain the same higher temp we see when we tune with NPG+.
We should try to control for temperature to minimize variability due to temperature related factors - maybe not running fans with water+water wetter to maintain the same higher temp we see when we tune with NPG+.
07-15-2007, 10:20 PM
#60
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Honestly. You guys lost me 2 pages ago.. Does any of this break down why the ARC is so much better?
Or did we all just get side tracked on something else.. I cant tell as i have no idea what the hell your discussing..
Or did we all just get side tracked on something else.. I cant tell as i have no idea what the hell your discussing..