Whats the Best radiator for extreame heat?
07-18-2007, 07:47 AM
#81
Well I've seen data for and against using something like Evans vs. distilled water and a surfactant/anti-corrosion additive. I have not seen a study that utilized multiple thermocouples all around the heads and/or in the water jackets themselves to actually chart real time temperature fluctuations. If Evans had actually done this then I think it would have been in their best interest to publish it (if the results were favorable).
Still waiting on a reply from them...
Interestingly, I can not find a single report on the 'net of a motor failure for someone running Evans. I have found anecdotal data of water pump failures and thermostat failures with resultant boiling of Evans past 370F and still the motor was unharmed from recognizable physical damage...
Still waiting on a reply from them...
Interestingly, I can not find a single report on the 'net of a motor failure for someone running Evans. I have found anecdotal data of water pump failures and thermostat failures with resultant boiling of Evans past 370F and still the motor was unharmed from recognizable physical damage...
Last edited by rcdash; 07-18-2007 at 07:50 AM.
07-18-2007, 01:38 PM
#82
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The purpose of the coolant temp sensor that drives the ecu is primarily to provide data for the fuel enrichment portion to compensate for cold starts and summer protection against overheats. Assuming the thermostat is wide open all the ecu can do is decrease ignition advance and enrichen the fuel mixture.....................eventually it might do an emergency shut down but I've never seen that as the engine keeps going [no coolant] until something locks up from lack of lubrication.
All Nissan engines have a wonderful cylinder head over heat indicator called the plastic bodied knock sensor bolted to the head.
We replace them by the gross each year on old and newish Q, J30, G20, Maxima, etc.
The plastic has a 300F rating then it cracks throwing a KS code.
My major concern is that those with stock oem ecu don't allow the sensor to read above 195-200F or they get outside the NORMAL mixture portion and into what I call summer protection mode.
All Nissan engines have a wonderful cylinder head over heat indicator called the plastic bodied knock sensor bolted to the head.
We replace them by the gross each year on old and newish Q, J30, G20, Maxima, etc.
The plastic has a 300F rating then it cracks throwing a KS code.
My major concern is that those with stock oem ecu don't allow the sensor to read above 195-200F or they get outside the NORMAL mixture portion and into what I call summer protection mode.
07-23-2007, 03:41 PM
#86
Received a reply from Doug Evans himself, take as you will:
Dear [Sir]:
Water, below its boiling point, has excellent thermal conductivity and is superior to any glycol for transferring heat. Unfortunately, water boils at easily reachable temperatures in an automobile engine. Water vapor (steam) has only 4.0% of the thermal conductivity that liquid water has.
The purpose of an engine cooling system is to control metal temperatures. The bulk temperature of your water-based coolant is already near the boiling point of water. At critical locations in the cylinder head of your stressed engine, water-based coolant will exceed its boiling point and water vapor will interrupt the heat transfer between hot metal and liquid coolant. That is where you will get a local temperature spike in the metal, causing detonation.
It is easy to think that a pressurized cooling system prevents the localized boiling. If the pressure increase seen in a pressurized expansion tank were caused by liquid expansion only, the pressure there would increase by only 3 or 4 psi. Pressure increases beyond 3 or 4 psi can only be caused by the presence of vapor in the engine, vapor located at the hottest places. It is this vapor that forces you to run at less than optimum spark settings to avoid detonation. (Engine control systems with knock sensors will automatically adjust to a less optimum setting.)
Liquid to metal (and vice versa) heat transfer works well. Transferring heat through a gas works rather poorly. Heat transfer from the radiator to the air requires a substantial delta T and is generally the greatest factor determining the bulk coolant temperature. That is why there is so little bulk temperature difference between 100% water and 50% water coolants. The bulk temperature with NPG+ coolant will increase very slightly or not at all.
There are water-based coolants and Evans waterless coolants. All water-based coolants, regardless of formulation or other ingredients, make water vapor where it limits performance. The bulk coolant temperature of NPG+ is always much colder than the boiling point of NPG+ and any localized vapor immediately condenses into surrounding fluid, which is why there is no film boiling.
Evans NPG+ coolant has been a commercial product since 2001 and there are more than 100,000 installations worldwide. The product is beyond the experimental stage and for that reason Evans Cooling Systems is not interested in sponsoring tests v. water-based products.
Regarding installing NPG+ at the performance shop, NPG+ works best when the water content is the least possible (OK below 5%, best below 3%). Use a refractometer (available from Evans) to make sure you have got it right.
Thank you for your interest in Evans NPG+ waterless coolant and good luck on your high performance project.
Kind Regards,
Doug Evans
Water, below its boiling point, has excellent thermal conductivity and is superior to any glycol for transferring heat. Unfortunately, water boils at easily reachable temperatures in an automobile engine. Water vapor (steam) has only 4.0% of the thermal conductivity that liquid water has.
The purpose of an engine cooling system is to control metal temperatures. The bulk temperature of your water-based coolant is already near the boiling point of water. At critical locations in the cylinder head of your stressed engine, water-based coolant will exceed its boiling point and water vapor will interrupt the heat transfer between hot metal and liquid coolant. That is where you will get a local temperature spike in the metal, causing detonation.
It is easy to think that a pressurized cooling system prevents the localized boiling. If the pressure increase seen in a pressurized expansion tank were caused by liquid expansion only, the pressure there would increase by only 3 or 4 psi. Pressure increases beyond 3 or 4 psi can only be caused by the presence of vapor in the engine, vapor located at the hottest places. It is this vapor that forces you to run at less than optimum spark settings to avoid detonation. (Engine control systems with knock sensors will automatically adjust to a less optimum setting.)
Liquid to metal (and vice versa) heat transfer works well. Transferring heat through a gas works rather poorly. Heat transfer from the radiator to the air requires a substantial delta T and is generally the greatest factor determining the bulk coolant temperature. That is why there is so little bulk temperature difference between 100% water and 50% water coolants. The bulk temperature with NPG+ coolant will increase very slightly or not at all.
There are water-based coolants and Evans waterless coolants. All water-based coolants, regardless of formulation or other ingredients, make water vapor where it limits performance. The bulk coolant temperature of NPG+ is always much colder than the boiling point of NPG+ and any localized vapor immediately condenses into surrounding fluid, which is why there is no film boiling.
Evans NPG+ coolant has been a commercial product since 2001 and there are more than 100,000 installations worldwide. The product is beyond the experimental stage and for that reason Evans Cooling Systems is not interested in sponsoring tests v. water-based products.
Regarding installing NPG+ at the performance shop, NPG+ works best when the water content is the least possible (OK below 5%, best below 3%). Use a refractometer (available from Evans) to make sure you have got it right.
Thank you for your interest in Evans NPG+ waterless coolant and good luck on your high performance project.
Kind Regards,
Doug Evans
07-23-2007, 08:24 PM
#87
Sharif,
There should be 0% water in my car right now - completely dried out, yes? Perfect time to test the Evans...
I'm sure others would love to hear if your tuning experience on Evans matches what they claim...
EDIT: Mr. Pressley, VP of Evans Cooling, invited me to give him a call - so I did of course! Very nice gentlemen with a lot of experience in cooling high performance machines. He related some of the test work they have done measuring cylinder head temperatures. The basic point is that at idle, the bulk coolant temp may sit a few degrees higher due to the decreased thermal conductivity, but as bulk temperatures rise to temps where localized water vapor begins to form, the Evans product will outperform water-based coolants when it comes to control of the cylinder head metal temperatures. At critical temperatures, above 220-230 coolant bulk temperature, they have noted that metal temps in one of their tests was above 700F using water based coolant but 150-200F cooler with Evans.
I am very much looking forward to see how well the Evans NPG+ performs in my built/turbo G...
There should be 0% water in my car right now - completely dried out, yes? Perfect time to test the Evans...
I'm sure others would love to hear if your tuning experience on Evans matches what they claim...EDIT: Mr. Pressley, VP of Evans Cooling, invited me to give him a call - so I did of course! Very nice gentlemen with a lot of experience in cooling high performance machines. He related some of the test work they have done measuring cylinder head temperatures. The basic point is that at idle, the bulk coolant temp may sit a few degrees higher due to the decreased thermal conductivity, but as bulk temperatures rise to temps where localized water vapor begins to form, the Evans product will outperform water-based coolants when it comes to control of the cylinder head metal temperatures. At critical temperatures, above 220-230 coolant bulk temperature, they have noted that metal temps in one of their tests was above 700F using water based coolant but 150-200F cooler with Evans.
I am very much looking forward to see how well the Evans NPG+ performs in my built/turbo G...
Last edited by rcdash; 07-24-2007 at 06:26 AM.
07-25-2007, 04:49 AM
#88
Raj,
Tell you what. I'll also do this test myself. (na)
Using the crummy 91 octane we have here in CA, I know the knock sensors are detecting ping and the ECU responds by pulling timing. I know this to be true because when I fuel up with a mix of race gas and 91 octane, the power curve moves up and the curves are smoother and much more repeatable.
So by knowing a ping incuced power reduction is continually present on this engine (when using 91 octane) it indicates a potential here...
There are 2 basic ways to induce ping.
1) an increase in adiabatic compression temperatures beyond the limit of the fuel.
and
2) localized overheating of specific areas of the cylinder walls which results in pre-spark ignition and detonation.
...
Because power is limited by the use of 91 octane it also means there may be a potential for power gains if localized overheating is the cause.
I don't necessarily need to tune the engine for this test. Our ECU is constantly in a state of auto tuning. This is obvious because putting in higher octane fuel results in significant changes in performance. (I logged an advance in timing with higher octane fuel)
If localized overheating of the cylinder walls is the cause of the pre-ignition and detonation and if NPG+ works as advertised, I should be able to measure an increase or change in performance by using it.
If the (presumed) hot spots are quenched and detonation is reduced accordingly (while using only 91 octane) it should result in a measurable increase of power.
I'll test it and post the dyno results here.
Tell you what. I'll also do this test myself. (na)
Using the crummy 91 octane we have here in CA, I know the knock sensors are detecting ping and the ECU responds by pulling timing. I know this to be true because when I fuel up with a mix of race gas and 91 octane, the power curve moves up and the curves are smoother and much more repeatable.
So by knowing a ping incuced power reduction is continually present on this engine (when using 91 octane) it indicates a potential here...
There are 2 basic ways to induce ping.
1) an increase in adiabatic compression temperatures beyond the limit of the fuel.
and
2) localized overheating of specific areas of the cylinder walls which results in pre-spark ignition and detonation.
...
Because power is limited by the use of 91 octane it also means there may be a potential for power gains if localized overheating is the cause.
I don't necessarily need to tune the engine for this test. Our ECU is constantly in a state of auto tuning. This is obvious because putting in higher octane fuel results in significant changes in performance. (I logged an advance in timing with higher octane fuel)
If localized overheating of the cylinder walls is the cause of the pre-ignition and detonation and if NPG+ works as advertised, I should be able to measure an increase or change in performance by using it.
If the (presumed) hot spots are quenched and detonation is reduced accordingly (while using only 91 octane) it should result in a measurable increase of power.
I'll test it and post the dyno results here.
07-25-2007, 05:15 AM
#89
BTW,
I already have 50-50 antifreez/water coolant in the Z. Getting the water completely out will be a bit of a challenge.
I propose flushing the water out with multiple drains and refills of pure antifreez before filling up with the NPG+.
After two or three cycles of pure antifreez flushing and coolant circulation, the water should be pretty much gone. I can then drain the system as best as possible. The only thing left in the engine will be pure glycol(s). It should then be ready for a NPG+ fill up.
1) Could you please run this by Mr. Pressley for his thoughts on this.
2) Ask how flush cycles should be performed.
3) Is there any particular brand of antifreez that should be used as the flushing agent?
4) Is there any else I should be aware of or are there any recomendations he can offer before starting the test?
5) Would Mr. Pressley be willing to donate the flushing agent and NPG+?
I will donate a day of my time to do a well controlled pre/post dyno test.
All pre/post testing will beformed on a Dynapack on the same day without ever removing the car from the dyno. All on the same tank of gas, with controlled atmospheric test conditions and SAE corrections. All engine data vitals will logged via the Cipher data logger.
If NPG+ shows results, I'm sure it will rapidly convert the 350Z/G35 enthusiast community (us
) over to a new coolant.
I already have 50-50 antifreez/water coolant in the Z. Getting the water completely out will be a bit of a challenge.
I propose flushing the water out with multiple drains and refills of pure antifreez before filling up with the NPG+.
After two or three cycles of pure antifreez flushing and coolant circulation, the water should be pretty much gone. I can then drain the system as best as possible. The only thing left in the engine will be pure glycol(s). It should then be ready for a NPG+ fill up.
1) Could you please run this by Mr. Pressley for his thoughts on this.
2) Ask how flush cycles should be performed.
3) Is there any particular brand of antifreez that should be used as the flushing agent?
4) Is there any else I should be aware of or are there any recomendations he can offer before starting the test?
5) Would Mr. Pressley be willing to donate the flushing agent and NPG+?
I will donate a day of my time to do a well controlled pre/post dyno test.
All pre/post testing will beformed on a Dynapack on the same day without ever removing the car from the dyno. All on the same tank of gas, with controlled atmospheric test conditions and SAE corrections. All engine data vitals will logged via the Cipher data logger.
If NPG+ shows results, I'm sure it will rapidly convert the 350Z/G35 enthusiast community (us
) over to a new coolant.
Last edited by Hydrazine; 07-25-2007 at 05:30 AM.
07-25-2007, 05:24 AM
#90
Q45tech,
Do you have the temperature resistance curves I should use for this test?
If coolant temperature increases with NPG+ I don't want the ECU pulling timing for it.
I'll use a resistor or potentiometer to correct for the change in coolant temperature.
I want this test to focus on the effect of ping controlled spark timing.
Do you have the temperature resistance curves I should use for this test?
If coolant temperature increases with NPG+ I don't want the ECU pulling timing for it.
I'll use a resistor or potentiometer to correct for the change in coolant temperature.
I want this test to focus on the effect of ping controlled spark timing.
Last edited by Hydrazine; 07-25-2007 at 05:51 AM.
07-25-2007, 06:04 AM
#91
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Miscalibrating the sensor to ecu has its risks since gasoline vapor spraying and cooling cylinder has a definite knock vs air temperature component.
Why refineries adjust gasoline for the 4 different climate times to compensate for air temperature. Start of winter [fall] vs deep winter vs spring vs summer.......the so called volatility index.
No point in fooling ecu via temperature and loosing all you gain by increased knock count from hotter heads.
Your FSM will have a section on testing sensor:
Graph the 3 temperature vs resistance values given and extrapolate the curve [ie] say 300-330 ohms = 176F..........the sensor resistance drops as the temps go up so about ~~2 ohms per degree so 0-25 ohms might be safe.
I use 10-12 ohms and get a 5F change but that's on an older Q each individual sensor will be slightly different +- a few %.
Read your scanner reported temp vs actual sensor resistance and develop a chart for your own individual sensor.
http://www.priuscar.com/ect_sensor_graph.htm
http://www.techno-fandom.org/~hobbit/cars/ect/
Why refineries adjust gasoline for the 4 different climate times to compensate for air temperature. Start of winter [fall] vs deep winter vs spring vs summer.......the so called volatility index.
No point in fooling ecu via temperature and loosing all you gain by increased knock count from hotter heads.
Your FSM will have a section on testing sensor:
Graph the 3 temperature vs resistance values given and extrapolate the curve [ie] say 300-330 ohms = 176F..........the sensor resistance drops as the temps go up so about ~~2 ohms per degree so 0-25 ohms might be safe.
I use 10-12 ohms and get a 5F change but that's on an older Q each individual sensor will be slightly different +- a few %.
Read your scanner reported temp vs actual sensor resistance and develop a chart for your own individual sensor.
http://www.priuscar.com/ect_sensor_graph.htm
http://www.techno-fandom.org/~hobbit/cars/ect/
07-25-2007, 06:26 AM
#92
I can certaintly do the test without any kind of temperature compensation but it may be compromising a potential gain...
OK, if there is any substantial difference in average coolant temperature, I'll test it with and without coolant temperature compensation.
Either way, we will know the direction and magnitude of performance change.
OK, if there is any substantial difference in average coolant temperature, I'll test it with and without coolant temperature compensation.
Either way, we will know the direction and magnitude of performance change.
07-25-2007, 01:54 PM
#93
New Member
iTrader: (6)
Not really evidence, but a little bit of anecdotal info (and back on topic)...
I recently read a thread on here about someone's dyno results. They listed their coolant temps along with power and torque numbers. Their starting temp was somewhere in the 180's (F) and the last temp was in the 220 (F) region. This was after 5 dyno pulls.
I have a Koyo 1 7/16" rad, Nismo T-stat, Samco hoses, and 70/30 water/coolant mix with a bottle of Water-Wetter. I recently made 30 pulls on the dyno in an enclosed shop with a 92 degree ambient temp. My starting temp was 177 (F), my ending temp was 178 (F). Like I said, this isn't scientific evidence that the Koyo is a good radiator, but I'm convinced.
I recently read a thread on here about someone's dyno results. They listed their coolant temps along with power and torque numbers. Their starting temp was somewhere in the 180's (F) and the last temp was in the 220 (F) region. This was after 5 dyno pulls.
I have a Koyo 1 7/16" rad, Nismo T-stat, Samco hoses, and 70/30 water/coolant mix with a bottle of Water-Wetter. I recently made 30 pulls on the dyno in an enclosed shop with a 92 degree ambient temp. My starting temp was 177 (F), my ending temp was 178 (F). Like I said, this isn't scientific evidence that the Koyo is a good radiator, but I'm convinced.
07-25-2007, 05:24 PM
#94
Originally Posted by Hydrazine
BTW,
I already have 50-50 antifreez/water coolant in the Z. Getting the water completely out will be a bit of a challenge.
I propose flushing the water out with multiple drains and refills of pure antifreez before filling up with the NPG+.
After two or three cycles of pure antifreez flushing and coolant circulation, the water should be pretty much gone. I can then drain the system as best as possible. The only thing left in the engine will be pure glycol(s). It should then be ready for a NPG+ fill up.
1) Could you please run this by Mr. Pressley for his thoughts on this.
2) Ask how flush cycles should be performed.
3) Is there any particular brand of antifreez that should be used as the flushing agent?
4) Is there any else I should be aware of or are there any recomendations he can offer before starting the test?
5) Would Mr. Pressley be willing to donate the flushing agent and NPG+?
I will donate a day of my time to do a well controlled pre/post dyno test.
All pre/post testing will beformed on a Dynapack on the same day without ever removing the car from the dyno. All on the same tank of gas, with controlled atmospheric test conditions and SAE corrections. All engine data vitals will logged via the Cipher data logger.
If NPG+ shows results, I'm sure it will rapidly convert the 350Z/G35 enthusiast community (us ) over to a new coolant.
I already have 50-50 antifreez/water coolant in the Z. Getting the water completely out will be a bit of a challenge.
I propose flushing the water out with multiple drains and refills of pure antifreez before filling up with the NPG+.
After two or three cycles of pure antifreez flushing and coolant circulation, the water should be pretty much gone. I can then drain the system as best as possible. The only thing left in the engine will be pure glycol(s). It should then be ready for a NPG+ fill up.
1) Could you please run this by Mr. Pressley for his thoughts on this.
2) Ask how flush cycles should be performed.
3) Is there any particular brand of antifreez that should be used as the flushing agent?
4) Is there any else I should be aware of or are there any recomendations he can offer before starting the test?
5) Would Mr. Pressley be willing to donate the flushing agent and NPG+?
I will donate a day of my time to do a well controlled pre/post dyno test.
All pre/post testing will beformed on a Dynapack on the same day without ever removing the car from the dyno. All on the same tank of gas, with controlled atmospheric test conditions and SAE corrections. All engine data vitals will logged via the Cipher data logger.
If NPG+ shows results, I'm sure it will rapidly convert the 350Z/G35 enthusiast community (us
) over to a new coolant.. Will call him in the am... Can you PM me the address where he should send the stuff should he agree...
07-25-2007, 05:36 PM
#95
Originally Posted by i8acobra
Not really evidence, but a little bit of anecdotal info (and back on topic)...
I recently read a thread on here about someone's dyno results. They listed their coolant temps along with power and torque numbers. Their starting temp was somewhere in the 180's (F) and the last temp was in the 220 (F) region. This was after 5 dyno pulls.
I have a Koyo 1 7/16" rad, Nismo T-stat, Samco hoses, and 70/30 water/coolant mix with a bottle of Water-Wetter. I recently made 30 pulls on the dyno in an enclosed shop with a 92 degree ambient temp. My starting temp was 177 (F), my ending temp was 178 (F). Like I said, this isn't scientific evidence that the Koyo is a good radiator, but I'm convinced.
I recently read a thread on here about someone's dyno results. They listed their coolant temps along with power and torque numbers. Their starting temp was somewhere in the 180's (F) and the last temp was in the 220 (F) region. This was after 5 dyno pulls.
I have a Koyo 1 7/16" rad, Nismo T-stat, Samco hoses, and 70/30 water/coolant mix with a bottle of Water-Wetter. I recently made 30 pulls on the dyno in an enclosed shop with a 92 degree ambient temp. My starting temp was 177 (F), my ending temp was 178 (F). Like I said, this isn't scientific evidence that the Koyo is a good radiator, but I'm convinced.
07-28-2007, 08:42 AM
#97
New Member
iTrader: (6)
Originally Posted by rcdash
If your temps never even approach 190F (thanks to the Koyo and that coolant mix), then I don't think you'd see much benefit from something like NPG+. Just curious what was ambient temp that day if you recall?
). Ambient in the shop was 92 (F).
07-28-2007, 08:52 AM
#98
We did go off on a bit of a tangent, but all related to cooling at least...
I see you listed the ambient temp in your original post (sorry) - looks like that Koyo is definitely working for you. Have you noticed any increased temps on the track or street? Are you FI?
I see you listed the ambient temp in your original post (sorry) - looks like that Koyo is definitely working for you. Have you noticed any increased temps on the track or street? Are you FI?
07-30-2007, 10:59 AM
#99
Registered User
Originally Posted by MartyG35
how big is the Arc radiator compared to the stock ones?
Originally Posted by Andy@Performance
Same size as stock.
Originally Posted by rcdash
All evidence indicates that it works and if you live in a warm climate, I don't think you need look further for a solution... The only issue would be the low boiling point. I am considering redline water wetter + distilled water + higher pressure radiator cap, but it would mean I would have to change the mix in the winter (here in NC it occasionally drops to freezing).
and i didn`t get any sign of overheating am still using the stock gauge last year i`ve used the 50/50 mix of water and anti-freeze it went over the 1/2 mark but now it will stay below the 1/2 all the time i guess the water wetter did its job.
