Air to Water Intercooler?

[NashMan]

me my self i have played with both system's

witch do i like more ummm both have ups and down's



a2a

pro's
alot lighter
alot more simple
alot more cfm can be had (street car)
factory car's run them cause there cheaper

con's

stop and go
4x4ing
low speed while going up hill's
towing
rally racing prone to damage the cooler in facing front words
heat soak


a2w

will all ways be just as cold s out side are or (cooler if you run additives)
intake temps have nice curve
stealth install
shorter ic piping most of the time
can run no bov if piping is short enough
less pressure drop

cons

weight
Little more complex
space
can not flow as much cfm ( street car)


the last one i did i used a factory ac condenser as the rad and used no fan and had no issues even in summer

then ran vw e pump

and pwr nock off

and rci tank

and ran the pump off the ignition

 

[ma71supraturbo]

Since you insist.

The thermodynamic losses you speak off (entropy) even with three energy state conversions of the L2A setup is less than the A2A setup. Why? Because of the Specific heat capacity of water.

In the end it is about energy transfer efficiencies at each point which the L2A has advantages not to include mass (which is a EBC twist away anyway). Particularly, position of the W2A heat exchanger can be better used for disipiation and or optimization of the air flow around the heat exchanger which means that it can also allow for better thermal rejection from radiation/convection of the asphalt.

Throw in some dry ice or a system exactly like Ford has on their Lightning, and then there is a no win for A2A.

If water was an absolutely perfect conductor of heat, then this discussion would be pointless, correct? It would be able to transfer all of the heat from the intercooler to the heat exchanger... But its not a perfect conductor of heat -- even though it is better than air.

You are still and always going to be limited by the ability of the L2A's heat exchanger to transfer heat from the liquid to the ambient air. This transfer of heat is based only on:

* the temperature difference between the heat exchanger and the environment
* the heat transfer coefficient for aluminum and air
* the surface area of the heat exchanger


Since space is a limiting constraint, you cannot fit a L2A radiator that has more surface area than an A2A intercooler. The maximum amount of heat that can be transferred/time is finite for a given set of conditions.

Since water is not a perfect conductor of heat, not all of the available heat that can be transferred will be taken. Saying anything else is like running a car on water -- it violates the conservation of energy. Your argument that water is better than air would be valid only if we were using air inside a L2A intercooler instead of liquid. But we're not -- we're comparing a design with 1 heat exchanger (the IC) with a design that uses 2 (the IC and the radiator)


The thermal mass of water acts like a damper -- it slows radical temperature changes, but once in a steady state condition, it will always have higher IATs than an air to air (again assuming both are limited by the same surface area constraints).

There are plenty of other advantages of L2A (pressure drop, the thermal mass's dampening effect, the ability to run sub-ambient temperatures using ice etc). But maximum thermodynamic efficiency (in steady-state) is not one of them.

 

[Zumtizzle]

Ian: Who makes the water heat exchanger? PWR?

 

[7thousandpiecesMGTE]

Google Thermal Shock.

Is this from your experience or theory/better safe than sorry kinda input?
I thought that high heat tranfers metals such as aluminum were more resistant to thermal shock. I personally have never heard of an intercooler cracking from a sprayer system.... Also I was going to go with co2 not no2 as I think the no2 would evaporate more quickly and give lower temps but its pricey and the risk of thermal shock is higher.

I'm keeping my A2A setup, but I will be tuning with a MAP ECU2 and only have two switchable map settings. i wanted a hi / low kinda deal but this scares me:

I also found tuning was easier with the W2A as you don't have such a wide variation of intake temps to program compensations for.

ie: pull in to fill up with fuel come out and try to restart the car with an A2A that's heat soaked into the twilight zone of AIT Compensation that's pulling fuel and messing with timing and it can take a couple of minutes of cranking to get it to fire.

I ended up adding a cranking compensation to get around this.

I really dont want to do have to do this and was hoping spraying the IC might help this.... maybe just cold water if its true co2 will crack it?

 

[ma71supraturbo]

I really dont want to do have to do this and was hoping spraying the IC might help this.... maybe just cold water if its true co2 will crack it?

Cheaper intercoolers are probably more prone to cracking, but I've never seen or heard of an intercooler cracking with a H20 sprayer (I used one myself for quite a while on the silver car based on the plumbing/tank for the headlight squirters). I don't like the idea of CO2/NO2 sprayers since they alter the oxygen content of air that often winds up being pulled through the the engine.


As for the IAT heat-soak issues, most of the times I've come across this as a problem, people had their IAT sensors in the manifold. If you install it in the charge piping or even on the cold side of the IC, the sensor itself will be less prone to heat soak (and it wont tell the ECU that the incoming air is unrealistically hot)

 

[IJ.]

that how big the one you have is but there should be more room there no?

Nope you need to leave room for the radiator so 6"x10" was about as big as would go in there.

Ian: Who makes the water heat exchanger? PWR?

It's part of a PWR kit.

Cheaper intercoolers are probably more prone to cracking, but I've never seen or heard of an intercooler cracking with a H20 sprayer (I used one myself for quite a while on the silver car based on the plumbing/tank for the headlight squirters). I don't like the idea of CO2/NO2 sprayers since they alter the oxygen content of air that often winds up being pulled through the the engine.


As for the IAT heat-soak issues, most of the times I've come across this as a problem, people had their IAT sensors in the manifold. If you install it in the charge piping or even on the cold side of the IC, the sensor itself will be less prone to heat soak (and it wont tell the ECU that the incoming air is unrealistically hot)

My sensors are always in the piping either side of the IC Jeff.

My findings/observations are all based on Empirical testing so your results may vary.

 

[figgie]

If water was an absolutely perfect conductor of heat, then this discussion would be pointless, correct? It would be able to transfer all of the heat from the intercooler to the heat exchanger... But its not a perfect conductor of heat -- even though it is better than air.

You are still and always going to be limited by the ability of the L2A's heat exchanger to transfer heat from the liquid to the ambient air. This transfer of heat is based only on:

* the temperature difference between the heat exchanger and the environment
* the heat transfer coefficient for aluminum and air
* the surface area of the heat exchanger


Since space is a limiting constraint, you cannot fit a L2A radiator that has more surface area than an A2A intercooler. The maximum amount of heat that can be transferred/time is finite for a given set of conditions.

Since water is not a perfect conductor of heat, not all of the available heat that can be transferred will be taken. Saying anything else is like running a car on water -- it violates the conservation of energy. Your argument that water is better than air would be valid only if we were using air inside a L2A intercooler instead of liquid. But we're not -- we're comparing a design with 1 heat exchanger (the IC) with a design that uses 2 (the IC and the radiator)


The thermal mass of water acts like a damper -- it slows radical temperature changes, but once in a steady state condition, it will always have higher IATs than an air to air (again assuming both are limited by the same surface area constraints).

There are plenty of other advantages of L2A (pressure drop, the thermal mass's dampening effect, the ability to run sub-ambient temperatures using ice etc). But maximum thermodynamic efficiency (in steady-state) is not one of them.

the system I describe is not breaking the 1st law of thermodynamic. What gave you that absurd notion? The system as I described and tested on aircraft is that efficency and temprature deviations are MINIMIZED with an L2A setup. At altitude, the L2A setup was still better than the A2A setup. Roughly in the 55-60% efficiency compared to the pale numbers in the 38%-40% for A2A when properly sized (that is for both systems. Key word is properly).

Just putting the Heat exchanger somewhere where there is better flow than that teenie tiny frontal area of the MKIII supra reaps efficency gains on its own (of course at the price of higher Cd). So no, the L2A system does have a better thermal dynamics efficiency than A2A when designed properly on the MKIII supra. The question is are the parts in the right place for both to leverage and exploit the efficiency gains? That would require some serious tunnel testing or some simulation models on air flow alone.

Edit: I am leaving this up but you win, I lose. Not in the mood to continue this..

 

[tErbo b00st]

a2a

con's

stop and go

a2w

will all ways be just as cold s out side are or (cooler if you run additives)
can run no bov if piping is short enough

Everyone keeps saying A2A has heat soak in stop and go? How the hell is that possible when your not building any boost in stop and go (I suppose there is some heat coming from piping heat soak and the turbo being hot, but comn). Not to mention your comparing apples to oranges by comparing a A2A w/ no fan and W2A w/ a fan. And, who is really worried about slightly less performance from a little heat soak when ur sitting in stop and go?

I can't believe there is a 7pg discussion on which is better. A2A will always outperform W2A in any kind of setup that does not warrant refilling or long cool down times. Its the simple fact that you can not cool the water to ambient, and thus it continues to store heat and raise the temperature of the water.

edit: I also want to add that the choice of intercooler does not determine whether a BOV is necessary in any way shape or form. If you use a BOV on an A2A the same conditions apply to a w2a

 

[Zumtizzle]

Everyone keeps saying A2A has heat soak in stop and go? How the hell is that possible when your not building any boost in stop and go (I suppose there is some heat coming from piping heat soak and the turbo being hot, but comn). Not to mention your comparing apples to oranges by comparing a A2A w/ no fan and W2A w/ a fan. And, who is really worried about slightly less performance from a little heat soak when ur sitting in stop and go?

I can't believe there is a 7pg discussion on which is better. A2A will always outperform W2A in any kind of setup that does not warrant refilling or long cool down times. Its the simple fact that you can not cool the water to ambient, and thus it continues to store heat and raise the temperature of the water.

Think about it....What cools the intercooler?

Why do air cooled VW Bugs and Lambos overheat at stop lights?

Okay, I agree on the Lazyness factor of Air to Air. (remember cars used to be aircooled.)

But water just cools better. How can water not cool to ambient temps? It's called a heat exchanger; which ironically this whole thread is about on many fronts.

Only cons of the Water to Air system is the fact you have to deal with corrosion running pure water. But i'm sure a mix can be run without seeing a major difference.

 

[tErbo b00st]

me my self i have played with both system's

witch do i like more ummm both have ups and down's



a2a

pro's
alot lighter
alot more simple
alot more cfm can be had (street car)
factory car's run them cause there cheaper

con's

stop and go
4x4ing
low speed while going up hill's
towing
rally racing prone to damage the cooler in facing front words
heat soak


a2w

will all ways be just as cold s out side are or (cooler if you run additives)
intake temps have nice curve
stealth install
shorter ic piping most of the time
can run no bov if piping is short enough
less pressure drop

cons

weight
Little more complex
space
can not flow as much cfm ( street car)


the last one i did i used a factory ac condenser as the rad and used no fan and had no issues even in summer

then ran vw e pump

and pwr nock off

and rci tank

and ran the pump off the ignition

Think about it....What cools the intercooler?

Why do air cooled VW Bugs and Lambos overheat at stop lights?

Because they are in an engine bay that traps the heat and the engine itself is generating a lot of heat. An intercooler is sitting in open air with relatively little heat passing through (unless your building boost)

 

[Enraged]

too bad these are so expensive:

 

[IJ.]

Everyone keeps saying A2A has heat soak in stop and go? How the hell is that possible when your not building any boost in stop and go (I suppose there is some heat coming from piping heat soak and the turbo being hot, but comn). Not to mention your comparing apples to oranges by comparing a A2A w/ no fan and W2A w/ a fan. And, who is really worried about slightly less performance from a little heat soak when ur sitting in stop and go?

I can't believe there is a 7pg discussion on which is better. A2A will always outperform W2A in any kind of setup that does not warrant refilling or long cool down times. Its the simple fact that you can not cool the water to ambient, and thus it continues to store heat and raise the temperature of the water.

edit: I also want to add that the choice of intercooler does not determine whether a BOV is necessary in any way shape or form. If you use a BOV on an A2A the same conditions apply to a w2a

Run an AIT sensor pre and post IC then come back and tell us what you've found....

Even if the Turbo Compressor discharge was only +5c over ambient given enough idle time the IC would heatsoak with no airflow.

I don't post bullshit and take offence that your post calls me a liar.

W2A is ACTIVE meaning it has a PUMP and a FAN so can cool while the car is sitting still or going slowly enough that an A2A won't be effective.

 

[tErbo b00st]

Run an AIT sensor pre and post IC then come back and tell us what you've found....

Even if the Turbo Compressor discharge was only +5c over ambient given enough idle time the IC would heatsoak with no airflow.

I don't post bullshit and take offence that your post calls me a liar.

W2A is ACTIVE meaning it has a PUMP and a FAN so can cool while the car is sitting still or going slowly enough that an A2A won't be effective.

but who cares if your IC is 20* above ambient when sitting in traffic? You trying to extract every bit of power as you move along at 5 mph?

 

[7thousandpiecesMGTE]

::fundy::::dead horse:: I feel a lock coming on....

 

[IJ.]

but who cares if your IC is 20* above ambient when sitting in traffic? You trying to extract every bit of power as you move along at 5 mph?

Because it affects the Temp based Compensations.....

Some of us take the time and effort to get our cars to have as good if not better drivability as stock in all conditions, guess you're one of the "It idles bad cos it's got big cams" muppets....

There's more to a tune than WOT Peak HP Numbers.

Are you an imbecile or reading impaired?

Seriously dude just STFU if you don't have a clue this shit is getting old.

 

[gaboonviper85]

Because they are in an engine bay that traps the heat and the engine itself is generating a lot of heat. An intercooler is sitting in open air with relatively little heat passing through (unless your building boost)

You are such a douche nozzel!

The res tank can be mounted in the trunk of the car which can have ac blowing on it...the intercooler can be mounted in the engine bay or in the passenger seat if you like...the heat exchanger/radiator an be mounted behind the from bumper....w2a systems have water pumps and hoses to move the water and keep it circulating threw it's ic,rad,res tank...it's not just a bowl of water!

W2a has it's place...a2a has it's place also....at just under 400hp IJ has data logged that the w2a was a much better system for him but it started to choke off at higher power...he has his proof of this and I can't see why he would make up such stories as he currently runs a2a as a water system takes up much space for his power goals!

Now to tackle your other dumbass comments...

An a2a ic is a heat exchanger...as hot air passes threw it cooler air will cool the charge....now the ic will also work the other way!!! An ic can heat air inside it just as easy as it can cool it....imagine it's 97deg F outside, your stuck in slow moving traffic, the pavement is 220deg f and your ic is about 7" from this pavement!!! That ic also is metal which is now hoarding in heat from the road and heating your air charge! You may not think this is a big deal but to people who run standalone ecu's this can really throw the cars tune off! Factory ecu has it already tuned in for this situation within reason. The water to air systems have a fan to cool it's own personal radiator and it works well but a fan on an a2a really doesn't work well as they don't move enough air for such a large system...

 

[Neodeuccio]

You are such a douche nozzel!

"Douche Nozzel"? That's a new one...

 

[Kristian_Wraae]

Before someone closes this thread I'd like to say that I'll like to see it kept open.

A2A and W2A are both good - both have advantages and disadvantages. Discussing which is better is silly.

So keep it civilized - we don't drive Hondas do we?

 

[tErbo b00st]

Because it affects the Temp based Compensations.....

Some of us take the time and effort to get our cars to have as good if not better drivability as stock in all conditions, guess you're one of the "It idles bad cos it's got big cams" muppets....

There's more to a tune than WOT Peak HP Numbers.

Are you an imbecile or reading impaired?

Seriously dude just STFU if you don't have a clue this shit is getting old.

But now your limiting your "peak power" by having hotter IAT by running a W2A. I use quotes around peak power, because at the end of the day you are trying to make power. And to lose 20-30 whp because you want your tuning 100% and not 99% through traffic seems illogical.

Or are you trying to say w2a on a daily driver or circuit car creates more power than an a2a?

 

[tErbo b00st]

Before someone closes this thread I'd like to say that I'll like to see it kept open.

A2A and W2A are both good - both have advantanges and disadvantages. Discussing which is better is silly.

So keep it civilized - we don't drive Hondas do we?

W2A is fantastic...when you can continually refill it to keep the water temperatures down. As the car runs the water continues to heats up more and more (up to a point) and your IATs rise with it.

I suppose if you want the coolest possible IAT's while idling (pointless) W2A might be the way to go. But I would really like to see an A2A with a fan compared to a W2A