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      05-04-2014, 03:41 PM   #1
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Thumbs up Liquid-to-Air instead of Air-to-Air

It's a air to water cooling system, heat soak plays a big part in these kind of intercooler systems.
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      05-04-2014, 03:51 PM   #2
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Originally Posted by Tonymiabmw View Post
It's a air to water cooling system, heat soak plays a big part in these kind of intercooler systems.
It is beyond me why they chose liquid to air for a street car. Same thing w the M5 but once that water boils, your performance is done. A well sized air to air would have been a better option IMHO.

Although 96F is still extremely hot.
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      05-04-2014, 04:23 PM   #3
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Quote:
Originally Posted by ASAP
Quote:
Originally Posted by Tonymiabmw View Post
It's a air to water cooling system, heat soak plays a big part in these kind of intercooler systems.
It is beyond me why they chose liquid to air for a street car. Same thing w the M5 but once that water boils, your performance is done. A well sized air to air would have been a better option IMHO.

Although 96F is still extremely hot.
Hopefully someone makes a larger heat exchanger and water tank. I'm in Miami so I deal with the same 80-90 degree weather 7-8 months of the year.
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      05-04-2014, 04:24 PM   #4
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Quote:
Originally Posted by Tonymiabmw
Hopefully someone makes a larger heat exchanger and water tank. I'm in Miami so I deal with the same 80-90 degree weather 7-8 months of the year.

Piggy and meth, and all those problems r gone but I would not trust that for the guys that will want to track this car.
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      05-04-2014, 05:22 PM   #5
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Quote:
Originally Posted by ASAP View Post
It is beyond me why they chose liquid to air for a street car. Same thing w the M5 but once that water boils, your performance is done. A well sized air to air would have been a better option IMHO.

Although 96F is still extremely hot.
Quote:
Originally Posted by Tonymiabmw View Post
Hopefully someone makes a larger heat exchanger and water tank. I'm in Miami so I deal with the same 80-90 degree weather 7-8 months of the year.
I hope you guys are just joking

Air to water cooler is a much more efficient way of cooling the charge air than a air to air intercooler.

The cooling capability of water is much higher than air (hence why we also have very few air cooled engines left...). The S55 has a separate water system that has a radiator mounted in the front, electric water pumps that circulate water from the cooler and through the chargecooler, then back to the radiator to cool down the water again.

Does the water in the intercooler system for the M5 really boil? Have never heard any M5 owner report that over on the M5 Boards...

What would be the benefit of a air to air cooler?
-Longer tubing = lag
-Lower cooling capacity than air to water

If using air as a cooling medium was better than water, I'm sure we would see a lot of air cooled engines...

Water cooling adds weight and needs more associated ancilliaries than a air to air intercooler, that's why early turbo cars had simple air to air intercoolers.
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      05-04-2014, 05:47 PM   #6
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Quote:
Originally Posted by Boss330 View Post
I hope you guys are just joking

Air to water cooler is a much more efficient way of cooling the charge air than a air to air intercooler.

The cooling capability of water is much higher than air (hence why we also have very few air cooled engines left...). The S55 has a separate water system that has a radiator mounted in the front, electric water pumps that circulate water from the cooler and through the chargecooler, then back to the radiator to cool down the water again.

Does the water in the intercooler system for the M5 really boil? Have never heard any M5 owner report that over on the M5 Boards...

What would be the benefit of a air to air cooler?
-Longer tubing = lag
-Lower cooling capacity than air to water

If using air as a cooling medium was better than water, I'm sure we would see a lot of air cooled engines...

Water cooling adds weight and needs more associated ancilliaries than a air to air intercooler, that's why early turbo cars had simple air to air intercoolers.
Even without getting into any sort of pros and cons... what kind of IC does a 911 turbo / GTR run? Pretty much the 2 best turbo cars on this planet.
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      05-04-2014, 06:04 PM   #7
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Quote:
Originally Posted by ASAP
Quote:
Originally Posted by Boss330 View Post
I hope you guys are just joking

Air to water cooler is a much more efficient way of cooling the charge air than a air to air intercooler.

The cooling capability of water is much higher than air (hence why we also have very few air cooled engines left...). The S55 has a separate water system that has a radiator mounted in the front, electric water pumps that circulate water from the cooler and through the chargecooler, then back to the radiator to cool down the water again.

Does the water in the intercooler system for the M5 really boil? Have never heard any M5 owner report that over on the M5 Boards...

What would be the benefit of a air to air cooler?
-Longer tubing = lag
-Lower cooling capacity than air to water

If using air as a cooling medium was better than water, I'm sure we would see a lot of air cooled engines...

Water cooling adds weight and needs more associated ancilliaries than a air to air intercooler, that's why early turbo cars had simple air to air intercoolers.
Even without getting into any sort of pros and cons... what kind of IC does a 911 turbo / GTR run? Pretty much the 2 best turbo cars on this planet.
Bugatti Veyron uses air to liquid intercoolers...

So does McLaren in their cars...

It will be interesting to see how efficient BMW has managed to deal with heat soak and track driving, but if they can cope with that, air to liquid is the best way to cool the charge air
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      05-04-2014, 06:09 PM   #8
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Quote:
Originally Posted by Boss330 View Post
Bugatti Veyron uses air to liquid intercoolers...

It will be interesting to see how efficient BMW has managed to deal with heat soak and track driving, but if they can cope with that, air to liquid is the best way to cool the charge air
A Bugatti Veyron, nor an M5 are track lap cars. The only convincing arguement that I would believe would be for the Mp4 but engine placement and size of the car there alone makes the liquid to air argument obvious.
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      05-04-2014, 06:16 PM   #9
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Quote:
Originally Posted by ASAP
Quote:
Originally Posted by Boss330 View Post
Bugatti Veyron uses air to liquid intercoolers...

It will be interesting to see how efficient BMW has managed to deal with heat soak and track driving, but if they can cope with that, air to liquid is the best way to cool the charge air
A Bugatti Veyron, nor an M5 are track lap cars. The only convincing arguement that I would believe would be for the Mp4 but engine placement and size of the car there alone makes the liquid to air argument obvious.
Not quite sure what you mean by engine placement making it obvious for the 12C and not for the 911? Both have their engines in the aft part of the car. If air to air was that much better, I'm sure McLaren could have found a way for some air ducts/intakes to cool the intercoolers?

Heat soak is the main issue that air to liquid cooling has to deal with. Control that and it's the more efficient cooling medium.

One way is to use the cooling capabilities of the AC, as a way to cool the radiator and avoid heat soak... Not sure BMW has done this though.
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      05-04-2014, 06:17 PM   #10
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Quote:
Originally Posted by ASAP
Quote:
Originally Posted by Boss330 View Post
Bugatti Veyron uses air to liquid intercoolers...

It will be interesting to see how efficient BMW has managed to deal with heat soak and track driving, but if they can cope with that, air to liquid is the best way to cool the charge air
A Bugatti Veyron, nor an M5 are track lap cars. The only convincing arguement that I would believe would be for the Mp4 but engine placement and size of the car there alone makes the liquid to air argument obvious.
The 'Ring taxi seems to cope well at the most demanding track
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      05-04-2014, 06:23 PM   #11
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Quote:
Originally Posted by Boss330 View Post
Not quite sure what you mean by engine placement making it obvious for the 12C and not for the 911? Both have their engines in the aft part of the car. If air to air was that much better, I'm sure McLaren could have found a way for some air ducts/intakes to cool the intercoolers?

Heat soak is the main issue that air to liquid cooling has to deal with. Control that and it's the more efficient cooling medium.
Rear engine and Mid engine are 2 totally different things...

The heat soak comment is a big deal.

Quote:
Originally Posted by Boss330 View Post
The 'Ring taxi seems to cope well at the most demanding track
It sure does for the 1 lap that it has to finish by showing off to a few people with no timing.
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      05-04-2014, 06:28 PM   #12
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Quote:
Originally Posted by ASAP View Post
It is beyond me why they chose liquid to air for a street car. Same thing w the M5 but once that water boils, your performance is done. A well sized air to air would have been a better option IMHO.

Although 96F is still extremely hot.

Lag.
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      05-04-2014, 07:20 PM   #13
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Quote:
Originally Posted by Boss330
Quote:
Originally Posted by ASAP View Post
It is beyond me why they chose liquid to air for a street car. Same thing w the M5 but once that water boils, your performance is done. A well sized air to air would have been a better option IMHO.

Although 96F is still extremely hot.
Quote:
Originally Posted by Tonymiabmw View Post
Hopefully someone makes a larger heat exchanger and water tank. I'm in Miami so I deal with the same 80-90 degree weather 7-8 months of the year.
I hope you guys are just joking

Air to water cooler is a much more efficient way of cooling the charge air than a air to air intercooler.

The cooling capability of water is much higher than air (hence why we also have very few air cooled engines left...). The S55 has a separate water system that has a radiator mounted in the front, electric water pumps that circulate water from the cooler and through the chargecooler, then back to the radiator to cool down the water again.

Does the water in the intercooler system for the M5 really boil? Have never heard any M5 owner report that over on the M5 Boards...

What would be the benefit of a air to air cooler?
-Longer tubing = lag
-Lower cooling capacity than air to water

If using air as a cooling medium was better than water, I'm sure we would see a lot of air cooled engines...

Water cooling adds weight and needs more associated ancilliaries than a air to air intercooler, that's why early turbo cars had simple air to air intercoolers.
Yes it does boil, these system are similar in my mind to Cobra/ford GT motor. A root style super charger with a/w intercooler under. Water tank, heat exchanger("radiator") that water gets pumped thru. They are efficient but they get heatsoaked. Cobra guys put larger water tanks(also you can put ice cubes in it) heat exchangers to avoid heat soak.
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      05-04-2014, 07:22 PM   #14
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Larger tank and heat exchanger which help.
Attached Images
  
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      05-04-2014, 08:46 PM   #15
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Quote:
Originally Posted by Boss330 View Post
Bugatti Veyron uses air to liquid intercoolers...

So does McLaren in their cars...

It will be interesting to see how efficient BMW has managed to deal with heat soak and track driving, but if they can cope with that, air to liquid is the best way to cool the charge air
I wonder if BMW dilutes the fluid with glycol for freeze protection for all vehicles, even those that are sold in climates that do not drop below freezing as it will hinder heat transfer capacity...
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      05-05-2014, 10:10 AM   #16
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Quote:
Originally Posted by Boss330 View Post
I hope you guys are just joking

Air to water cooler is a much more efficient way of cooling the charge air than a air to air intercooler.

The cooling capability of water is much higher than air (hence why we also have very few air cooled engines left...). The S55 has a separate water system that has a radiator mounted in the front, electric water pumps that circulate water from the cooler and through the chargecooler, then back to the radiator to cool down the water again.

Does the water in the intercooler system for the M5 really boil? Have never heard any M5 owner report that over on the M5 Boards...

What would be the benefit of a air to air cooler?
-Longer tubing = lag
-Lower cooling capacity than air to water

If using air as a cooling medium was better than water, I'm sure we would see a lot of air cooled engines...

Water cooling adds weight and needs more associated ancilliaries than a air to air intercooler, that's why early turbo cars had simple air to air intercoolers.
Very well put

I was about to post the same but you beat me to it .
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      05-05-2014, 11:26 AM   #17
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Quote:
Originally Posted by CanAutM3
Quote:
Originally Posted by Boss330 View Post
I hope you guys are just joking

Air to water cooler is a much more efficient way of cooling the charge air than a air to air intercooler.

The cooling capability of water is much higher than air (hence why we also have very few air cooled engines left...). The S55 has a separate water system that has a radiator mounted in the front, electric water pumps that circulate water from the cooler and through the chargecooler, then back to the radiator to cool down the water again.

Does the water in the intercooler system for the M5 really boil? Have never heard any M5 owner report that over on the M5 Boards...

What would be the benefit of a air to air cooler?
-Longer tubing = lag
-Lower cooling capacity than air to water

If using air as a cooling medium was better than water, I'm sure we would see a lot of air cooled engines...

Water cooling adds weight and needs more associated ancilliaries than a air to air intercooler, that's why early turbo cars had simple air to air intercoolers.
Very well put

I was about to post the same but you beat me to it .
I guess Porsche, Nissan, Mitsubishi and Subaru have all not figured this magic out yet. All of which build turbo track cars and have many mounds more years in turbo gas motors than BMW. My #1 guess is that this was done for product differentiation and nothing else.
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      05-05-2014, 11:27 AM   #18
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Lets also remember who the turbos for the N54 came from.
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      05-05-2014, 11:40 AM   #19
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Quote:
Originally Posted by ASAP View Post
I guess Porsche, Nissan, Mitsubishi and Subaru have all not figured this magic out yet. All of which build turbo track cars and have many mounds more years in turbo gas motors than BMW. My #1 guess is that this was done for product differentiation and nothing else.
Yes, Nissan, Mitsu, and Subaru all are not as worried about turbo lag and are more focused on keeping cost down. They used TMIC air-to-air for the most part, though a few FMIC on Mitsu products are around too at the expense of...more lag.

Porsche does not have cost control issues nearly as much but do they have packaging issues in their application. They are already running max radiators at the front, use their side vents for air intake, and vent through intercooler through the rear decklid. Where are they going to stick ANOTHER radiator and more cooling hoses? And then the question becomes whether or not it would gain anything in their application.

My guess is BMW saw the primary benefit being lag reduction and cooling in this platform and decided to go for it.
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      05-05-2014, 11:48 AM   #20
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Quote:
Originally Posted by ASAP View Post
I guess Porsche, Nissan, Mitsubishi and Subaru have all not figured this magic out yet. All of which build turbo track cars and have many mounds more years in turbo gas motors than BMW. My #1 guess is that this was done for product differentiation and nothing else.
Interresting to note that the less "performance oriented" models from BMW use air-to-air intercoolers...

It is a question of specific heat properties of fluids. Water can store 3300 times the quantity of energy for one degree of temperature elevation by volume compared to air (about 4x by mass). You need a lot of "air heat" to heat soak a water system...

Last edited by CanAutM3; 05-05-2014 at 12:01 PM..
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      05-05-2014, 12:01 PM   #21
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Quote:
Originally Posted by CanAutM3 View Post
Interresting to note that the less "performance oriented" models from BMW use air-to-air intercoolers...

It is a question of specific heat properties of fluids. Water can store 3300 times the quantity of energy for one degree of temperature elevation by volume compared to air. You need a lot of "air heat" to heat soak a water system...
I agree with you here but I'd like to know how much of that capacity is used up just by sitting still or warming up at the track and at what rate the heat is 'bled off' when driving full bore at a given MPH.

Hope that makes sense. An air to air intercooler heat soaks easily but also gets rid of heat soak quickly. A water to air intercooler does not heat soak easily but nor does it shed heat as easily. Let's identify the rates.
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      05-05-2014, 12:07 PM   #22
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Quote:
Originally Posted by JoeFromPA View Post
I agree with you here but I'd like to know how much of that capacity is used up just by sitting still or warming up at the track and at what rate the heat is 'bled off' when driving full bore at a given MPH.

Hope that makes sense. An air to air intercooler heat soaks easily but also gets rid of heat soak quickly. A water to air intercooler does not heat soak easily but nor does it shed heat as easily. Let's identify the rates.
Good point. The inverse is also true, due to the high specific heat of water, once heat soaked, a water system needs a lot of air to cool down.

To prevent heat soak, usually the radiator will be significantly larger than the intercooler, hence, in principle, there is more heat extraction capability in the system than there is to add heat (temperature delta and mass flow is also part of the equation). If BMW have done their homework right (which I suspect they did), the F8X intercooler should not heat soak.

Last edited by CanAutM3; 05-05-2014 at 12:25 PM..
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