Vortech Says This In Regards To Intercoolers/after. Do Y'all Concur?

84Ttop · Aug 18, 2014

Bullitt347 said:
Air/water is far more efficient at removing heat from the air charge. A typical air/water intercooler has an efficiency ratio of 4:1 whereas a air/air intercooler has an efficiency ratio of only 1:1. This is why air/water intercooler are so much smaller than your air/air type.

This exactly! While a setup to introduce fresh ice will always yield the best results, a closed loop a/w is hands down better when compared to a/a of comparable capacity

FastDriver · Aug 18, 2014

Right... so you kinda already said A/W was better, and now you said so again... still no explanation why. I'm on board when it comes to the ice-bucket actual "A-W" design, but that's specifically because the "coldness" doesn't need to come from the atmosphere. It comes from the ice and temperature of the water. Thus, the intake charge can actually be brought BELOW ambient temps.

I'm still not convinced about the A-W-A is more efficient. Water, obviously has more thermal capacity than air, but in A-W-A, all you end up doing is adding an additional thermal barrier. I'm imagining a "closed loop" system that to me means you've got two heat exchangers, now. One acting the same way as a radiator at the front of the car where the water transfers heat to the atmosphere, and on the other side I'm seeing another radiator/heat exchanger transferring heat away from intake charge and into the water. Heat is exchanged twice, instead of once, which is why I referred to it as, A-W-A. This isn't the same as the ice bucket A-W systems used commonly in drag racing to me. In drag racing, they can be repacked with ice after each run.

Obviously, the specific heat of water is higher, and thus the thermal capacity of water is greater. That's only good for a time until the water is heat soaked. At that point, efficiency of the systems is all that matters -- the ability to transfer heat from the air in the intake charge to the atmosphere...

Somehow, the concept above doesn't seem as effective to me as skipping the water and requiring only a single exchange, as in A-A. I see a huge advantage in the A-A systems in that they can not become heat soaked so long as Ambient air is flowing through the IC.

Disagreement from the A-W or A-W-A camp?

Seems like the A-A is simpler to design, less moving parts, less heat exchanges required. I can't see why adding another thermal barrier makes the system better if it isn't cooled below ambient in the first place.

Bullitt347 · Aug 18, 2014

Well, there is a reason that engines are cooled with water instead of air. It is just flat out more efficient. That being said............I have noticed that when Ford/Roush/Saleen do a supercharger they use air to water. In all of the EcoBoost applications (turbo) they use air to air. My guess is that it is a packaging issue.

FastDriver · Aug 18, 2014

All of those superchargers are roots/twin screw, right? which compress the air after the throttle body. I don't know if there's a sensible way to use an A-A intercooler on them.

Additionally, I wouldn't jump straight to what OEMs do as evidence of which is the better performing system. OEMs often significantly compromise boosted systems in the name of cost cutting and packaging instead of performance and reliability.

By the way, I hope my argument isn't offending anyone. Challenging an argument is my way of learning. Basically, I argue what makes sense to me, or sometimes what doesn't make sense in an attempt to hear/see the other side of the argument.

In honesty, I'm guessing that either system is good enough, and either can probably handle any given amount of power if it's designed well.

revhead347 · Aug 19, 2014

First of all, not all engines are cooled with water. Most engines are cooled with water, because it's cheaper to do so. It's also more compact. Airplane engines are almost always cooled with air, but a 200hp airplane engine will cost you $20,000 rebuilt. Cooling the engine with air directly is more efficient. The same way an A-A intercooler is more efficient. The laws of physics dictate it. Anytime another medium is used for heat transfer there is an efficency loss. The advantage of A-W-A intercooler is the ice bucket. You can artificially cool the air charge for a very short period of time by introducing ice. If it's just water running around in a circle, then there is no advantage. I'm waiting for vapor cycle intercooling. Now that would be more efficient.

Kurt

revhead347 · Aug 19, 2014

FastDriver said:
All of those superchargers are roots/twin screw, right? which compress the air after the throttle body. I don't know if there's a sensible way to use an A-A intercooler on them.

The old supercharged 3.8 in the 90s Cougar had a roots blower with an A-A. The plumbing on the blower was very counter-intuitive. The air actually entered the blower at the bottom, then came out the top, out the front of the car to an intercooler then back through another pipe behind the blower to the intake manifold that sat under the blower.

Kurt

Bullitt347 · Aug 19, 2014

revhead347 said:
First of all, not all engines are cooled with water. Most engines are cooled with water, because it's cheaper to do so. It's also more compact.

Kurt

We were/are talking about automobile engines, so throwing airplane engines into the mix is distracting at best and derails the discussion. The reason Porsche went away from air cooled engines is because they could not make the engine efficient enough to pass new emissions standards. It had to be water cooled to have an efficient combustion process. They did not have the advantage of the cooler air at 15K feet and higher altitudes. If air cooling was so efficient, I am sure that Porsche if anybody could have figured it out. In an automotive application, both air/air and air/water have their place. The simple fact is air/water has an efficiency ratio of 4:1. Air/air at best is only 1:1. And at best air/air is stuck at getting the air charge down to ambient, whereas air/water can cool off the air charge to less than ambient..........without adding ice to the equation.

Noobz347 · Aug 19, 2014

Bullitt347 said:
We were/are talking about automobile engines, so throwing airplane engines into the mix is distracting at best and derails the discussion. The reason Porsche went away from air cooled engines is because they could not make the engine efficient enough to pass new emissions standards. It had to be water cooled to have an efficient combustion process. They did not have the advantage of the cooler air at 15K feet and higher altitudes. If air cooling was so efficient, I am sure that Porsche if anybody could have figured it out. In an automotive application, both air/air and air/water have their place. The simple fact is air/water has an efficiency ratio of 4:1. Air/air at best is only 1:1. And at best air/air is stuck at getting the air charge down to ambient, whereas air/water can cool off the air charge to less than ambient..........without adding ice to the equation.

I disagree. I think it applies.

The way I've always understood this discussion and what few real articles I recall reading, is that air to air has always been more efficient. The greater the differences in temp between the cooling charge and heating charge, the greater the efficiency of the heat sink. So...

Toss in water conversion on top of that. The water in the system will never be as hot as the motor or as cool ambient air. That's a huge chunk of efficiency loss. More than what can be made up for with superior heat transfer properties of the cooling fluids.

I will see if I still have the article somewhere. The writer really pulled out the slide rule. hehe

Bullitt347 · Aug 19, 2014

IDK...........I mean how many cars do you see running at 15K feet altitude or higher? None. To make an air cooled engine as efficient as a water cooled engine it would be so large as to not be able to package it into a car. On warmer to hot days, air to air is really limited. Especially in stop and go traffic where heat soak comes into play. It has its place, like the EcoBoost engines. The fact remains that water has a 4 times superior efficiency ratio when it comes to removing heat. Air to air always has a much larger package due to it's in-efficiency ratio. By necessity it has to be 4 times larger than a similar air/water heat exchanger.

84Ttop · Aug 19, 2014

As taken from BellIntercoolers website:

A typical air-to-air intercooler for a street application achieves between 60% and 70% efficiency, an excellent/optimum design for road racing can approach close to 90% efficiency, but requires an adequate "budget!”

Typically, a liquid-to-air intercooler achieves higher efficiencies than an air-to-air intercooler, starting at 75% efficiency and reaching peaks of 95% efficiency. Another advantage is the optional use of ice as a coolant, which is the only way to reduce the charge-air temperature below the ambient air temperature.

Find the resource here: http://www.bellintercoolers.com/pages/techFAQ.html#FAQ_14

Bell Intercoolers makes a large amount of cooler cores a2a or a2w that are commercially available in almost every application base.
I found their FAQ to have some really good information actually. If you follow the link above you can see how they derive the intercooler efficiency. I won't flood the thread with too much info that was just copied and pasted.

revhead347 · Aug 19, 2014

Bullitt347 said:
We were/are talking about automobile engines, so throwing airplane engines into the mix is distracting at best and derails the discussion. The reason Porsche went away from air cooled engines is because they could not make the engine efficient enough to pass new emissions standards. It had to be water cooled to have an efficient combustion process. They did not have the advantage of the cooler air at 15K feet and higher altitudes. If air cooling was so efficient, I am sure that Porsche if anybody could have figured it out. In an automotive application, both air/air and air/water have their place. The simple fact is air/water has an efficiency ratio of 4:1. Air/air at best is only 1:1. And at best air/air is stuck at getting the air charge down to ambient, whereas air/water can cool off the air charge to less than ambient..........without adding ice to the equation.

I agree, an airplane does have a better supply of cool air. Porsche ran out of room in the back of the car for all the ducting to make it efficient. They switched to water cooling coincident with the introduction of a 4 valve head. I guess the new head have so much camshaft gibbons up in the top that they couldn't get the air fins in around it to meet the efficiency required by emissions standards. Although I think it was oversight from the 4 valve head itself, and the emissions was an excuse. Especially since their 4 valve engine didn't perform any better than the 2 valve engine when it came out. Bottom line, the fluid cooler is going to be subject to the same efficiency as the a2a once it reaches the front of the car.

Kurt

FastDriver · Aug 20, 2014

84Ttop said:
As taken from BellIntercoolers website:

A typical air-to-air intercooler for a street application achieves between 60% and 70% efficiency, an excellent/optimum design for road racing can approach close to 90% efficiency, but requires an adequate "budget!”

Typically, a liquid-to-air intercooler achieves higher efficiencies than an air-to-air intercooler, starting at 75% efficiency and reaching peaks of 95% efficiency. Another advantage is the optional use of ice as a coolant, which is the only way to reduce the charge-air temperature below the ambient air temperature.

Find the resource here: http://www.bellintercoolers.com/pages/techFAQ.html#FAQ_14

Bell Intercoolers makes a large amount of cooler cores a2a or a2w that are commercially available in almost every application base.
I found their FAQ to have some really good information actually. If you follow the link above you can see how they derive the intercooler efficiency. I won't flood the thread with too much info that was just copied and pasted.

Same source:

How can an air-to-air intercooler be more efficient than a water based intercooler?

There is an overwhelming quantity of ambient air available to cool an air-to-air core relative to the charge air thru the inside of the intercooler (The iced down water intercooler is the only exception to this argument.). At just 60 mph, with a 300 bhp engine at full tilt, the ambient air available to cool the intercooler is about ten times the amount of charge air needed to make the 300 hp. Whereas the water intercooler largely stores the heat in the water until off throttle allows a reverse exchange. Some heat is expelled from a front water cooler, but the temperature difference between the water and ambient air is not large enough to drive out much heat. Another way to view the situation is that ultimately the heat removed from the air charge must go into the atmosphere regardless of whether it's from an air intercooler or a water based intercooler. The problem with the water intercooler is that the heat has more barriers to cross to reach the atmosphere than the air intercooler. Like it or not, each barrier represents a resistance to the transfer of heat. The net result; more barriers, less heat transfer.

You have to ask yourself how they they measure efficiency. It's simply temp reduced by intercooler divided by the temp added by power adder. That says nothing of whether they're using water that's cooler than ambient, and it says nothing of the heat transfer rate that's taking place between the atmosphere and the intercooler/radiator. However, the quote above is very specific and basically validates my best guess.

FastDriver · Aug 20, 2014

Oh... here's an even better quote from the same site:

What are the relative merits of an air or water-cooled intercooler and which would suit my purposes best?
This depends on the circumstances. These circumstances are; street use, drag racing, or endurance racing (more than two minutes).

Street use: The air-to-air intercooler will prove superior in efficiency when sized properly.

Drag racing: The short spurt of power allows the iced water to cool the charge air to below ambient temperature.

Endurance racing: The air-to-air intercooler is clearly superior due to the shorter route of getting the heat out of the air charge and into the atmosphere. Endurance racing would preclude the use of ice water, thus negating the singular advantage of the water intercooler. Further, the air-to-air intercooler is (virtually, see comments below) maintenance free.

FastDriver · Aug 20, 2014

Bullitt347, I reeeeally don't want to offend you, man. If you start to feel angry about my counterpoints, I will stop... Just let me know.

The simple fact is air/water has an efficiency ratio of 4:1. Air/air at best is only 1:1.

Efficiency is not measured in this way. You're referring to specific heat... not efficiency. And, you're right, the difference in specific heat of water vs. air is about 4:1. http://www.iun.edu/~cpanhd/C101webnotes/matter-and-energy/specificheat.html

And at best air/air is stuck at getting the air charge down to ambient, whereas air/water can cool off the air charge to less than ambient..........without adding ice to the equation.

Ice or no ice, there is no way to reduce the air charge to less than ambient without bringing the water to below ambient AND there is no way to do that using the atmosphere to cool the water. Whether you use ice, colder water, or frozen carrots to cool the liquid heat exchanger doesn't matter. You can't do it continuously for long periods of time while driving on the street. You're limited to short bursts.

Bullitt347 said:
To make an air cooled engine as efficient as a water cooled engine it would be so large as to not be able to package it into a car.

Packaging is the largest reason for going with a water to air heat exchanger. Another acceptable reason is short bursts of cooling before the water is heat soaked.

On warmer to hot days, air to air is really limited. Especially in stop and go traffic where heat soak comes into play.

Careful. Without constantly adding some other cold medium, all intercoolers must eventually use the surrounding atmosphere, and are thus subject to the same concerns.

It has its place, like the EcoBoost engines. The fact remains that water has a 4 times superior efficiency ratio

"efficiency ratio" is not the correct term, as laid out above.

Air to air always has a much larger package due to it's in-efficiency ratio. By necessity it has to be 4 times larger than a similar air/water heat exchanger.

That's not true... At least the "4 times larger" part. Specific heat ratio does not necessitate that you need 4 times as much air in the intercooler, or a system 4 times as large.

90lxwhite · Aug 20, 2014

My biggest gripe/woe about the air/water is its another thing to have to worry about and added operating costs. While not a DD I still don't wanna have to add fluid every time i fill up w gas.

FastDriver · Aug 20, 2014

90lx, in an A-W-A system, you don't have to fill any fluid. It's a closed system. In an A-W system, you would have to at least cool the water.

You're right about it being extra things to worry about from a reliability standpoint, though.

Noobz347 · Aug 20, 2014

FastDriver said:
Bullitt347, I reeeeally don't want to offend you, man. If you start to feel angry about my counterpoints, I will stop... Just let me know.

Efficiency is not measured in this way. You're referring to specific heat... not efficiency. And, you're right, the difference in specific heat of water vs. air is about 4:1. http://www.iun.edu/~cpanhd/C101webnotes/matter-and-energy/specificheat.html

Ice or no ice, there is no way to reduce the air charge to less than ambient without bringing the water to below ambient AND there is no way to do that using something other than the atmosphere to cool the water. Whether you use ice, colder water, or frozen carrots to cool the liquid heat exchanger doesn't matter. You can't do it continuously for long periods of time while driving on the street. You're limited to short bursts.

Packaging is the largest reason for going with a water to air heat exchanger. Another acceptable reason is short bursts of cooling before the water is heat soaked.

Careful. Without constantly adding some other cold medium, all intercoolers must eventually use the surrounding atmosphere, and are thus subject to the same concerns.

"efficiency ratio" is not the correct term, as laid out above. That's not true... At least the "4 times larger" part. Specific heat ratio does not necessitate that you need 4 times as much air in the intercooler, or a system 4 times as large.

^This^

Test methods must be inspected when comparing competitor claims.

90lxwhite · Aug 20, 2014

Noobz347 said:
^This^

Test methods must be inspected when comparing competitor claims.

All I know is my dog ate my homework

Bullitt347 · Aug 20, 2014

FastDriver said:
Bullitt347, I reeeeally don't want to offend you, man. If you start to feel angry about my counterpoints, I will stop... Just let me know.

No problem, I enjoy a good debate/discussion as well as the next guy.

Efficiency is not measured in this way. You're referring to specific heat... not efficiency. And, you're right, the difference in specific heat of water vs. air is about 4:1. http://www.iun.edu/~cpanhd/C101webnotes/matter-and-energy/specificheat.html

Ice or no ice, there is no way to reduce the air charge to less than ambient without bringing the water to below ambient AND there is no way to do that using the atmosphere to cool the water. Whether you use ice, colder water, or frozen carrots to cool the liquid heat exchanger doesn't matter. You can't do it continuously for long periods of time while driving on the street. You're limited to short bursts.

I have watched the data-logs real time on an air/water supercharged car have 58* air inlet temp and seen outside ambient temp be 65* while cruising...not in boost...with no ice in the tank.

Packaging is the largest reason for going with a water to air heat exchanger. Another acceptable reason is short bursts of cooling before the water is heat soaked.

This is why I have an 8 gal water tank in the trunk............huge heat sink!

Careful. Without constantly adding some other cold medium, all intercoolers must eventually use the surrounding atmosphere, and are thus subject to the same concerns.

"efficiency ratio" is not the correct term, as laid out above. That's not true... At least the "4 times larger" part. Specific heat ratio does not necessitate that you need 4 times as much air in the intercooler, or a system 4 times as large.

The air/water intercooler core on my supercharged Mustang measures 14"X 5"X 6" The air/air intercooler on my sons 240SX measures 32"X 18"X 4.5" from a surface area standpoint I would say it is 4 times the size if not more. This example may or may not be relevant. Lol.

FastDriver · Aug 20, 2014

First, Kurt... awesome post as usual. I'd never heard of an A-A on a positive displacement blower. Where is the throttle body?

Bullitt... oh boy...I apologize for my lack of "efficient" explanation, in advance. First, let me ask you a related question. You've only looked at one of your mustang's heat exchangers. You didn't mention the volume of the other. In an A-W-A system, there are 2 heat exchanges happening. One is in the front of the car, and the other is between your blower and the intake. I have utterly no idea: what is the volume of the other heat exchanger? I can't imagine it's very large, but it has to be a large enough volume to account for the flow of the air charge and the flow of the water through it. The next questions are how much power can your heat exchanger system support? How much can your son's?

Now for the complicated part: I'm not denying that an A-A system may need more volume in the front mount intercooler (FMIC). However, it should not be 4x as much to reach the same heat energy transfer. That's because the temp difference in the FMIC and resulting heat transfer should be significantly higher in the A-A system.

It takes 4 times as much energy to increase the temperature of water the same as air. The more water that's in one of the A-W-A systems, the longer it will take to heat soak. That's kind of a good thing. However, it comes with a downside... it takes longer to bring the intercooler's temperature up. Or, conversely, once heat-soaked the FMIC has to work longer to cool it down. In an A-A system, the temp increases in the intercooler instantly. In the A-W-A system, energy has to transfer into the water, and then the water has to move to the FMIC before the FMIC is actually transferring heat away. After all, if the water in the FMIC is still as cold as ambient air, it's not exchanging any heat away from the system.

Back to sizing: if the overall A-A system is more efficient at transferring energy away from the intake charge, then it will not need 4x as much internal air volume to transfer the same amount of heat in a given amount of time. The temperature inside of the FMIC spikes immediately with the intake air charge, because the air inside of the FMIC is the air charge. Once the water warms up and you get the A-W-A system's intercooler up to its maximum temperature, it may transfer the energy away as fast as the A-A system... maybe faster since the design won't be the same (not really sure about that). However, the A-W-A's FMIC will probably never reach the same maximum temperature as the A-A FMIC.

Sorry for the complicated explanation, but there's one more piece to consider:

There are 3 types of heat exchange: Conduction, convection, and radiation. Heat transfer from air to the metal of the intercooler happens largely by convection, whereas water-metal heat transfer happens largely by conduction. Conduction is, I believe, more efficient. So in the exchange between the water and the metal of the intercooler, you would need less surface area and/or less temp difference for the same amount of heat energy transfer. However, this advantage is more than offset by the fact that you still have 2 air-metal heat exchanges happening with the A-W-A system, and the temp differences in each exchange are not as great as the A-A FMIC's ambient:intake charge temp difference.

Vortech Says This In Regards To Intercoolers/after. Do Y'all Concur?

They make new pistons every day, so why worry?

I was uncomfortably high & wearing a helmet

I have been doing it wrong this whole time

I was uncomfortably high & wearing a helmet

Apparently my ex-husband made that mistake.

Apparently my ex-husband made that mistake.

I have been doing it wrong this whole time

Stangnet Facilities Maint Tech... Er... Janitor

I have been doing it wrong this whole time

They make new pistons every day, so why worry?

Apparently my ex-husband made that mistake.

I was uncomfortably high & wearing a helmet

I was uncomfortably high & wearing a helmet

I was uncomfortably high & wearing a helmet

I'm kind of a She-Man

I was uncomfortably high & wearing a helmet

Stangnet Facilities Maint Tech... Er... Janitor

I'm kind of a She-Man

I have been doing it wrong this whole time

I was uncomfortably high & wearing a helmet

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