air/air vs water/air intercooler?

In reply to Boost_Crazy:

It's "COULDN'T CARE LESS"! Think about it could care less makes no sense...

In reply to jere:

I stand corrected. But I don't think the intercooler has a strong opinion either way. It's just along for the ride.

jere wrote: In reply to Boost_Crazy: It's "COULDN'T CARE LESS"! Think about it could care less makes no sense...

BTW, does your GM intercooler pump work? They wired them backwards from the factory on '04-5's...... *facepalms

Boost_Crazy wrote: Let's look at an extreme but common example where the intercooler gets a lot more work than in a typical sports car, and there is no shortage of frontal area- turbo diesel commercial trucks. They are on boost most of the time, at high boost pressures. But since they have plenty of room, they use air/air intercoolers.

Ford's 6.7 uses an air/water intercooler.

Its radiator/cooling circuit is shared with the oil and trans coolers (and another cooler I think... EGR cooler?) and has its own 122F thermostat. I do forget if it has a mechanical or electric water pump.

Boost_Crazy wrote: In reply to rslifkin:

Radiator heat exchangers have much smaller/closer/flatter tubes than an air/air intercooler. That is more surface area to transfer the heat from the working fluid to ambient air.

While this may be true, this is only one of the two heat exchangers in this system. You just transported the heat to the front of the car. Even if it was 100% efficient, you still have the heat exchanger that transfers the charge air heat to the water. Like I said, the water part just moves and stores the heat, it doesn't remove it.

I never suggested that it stored the heat until game over. In fact, that is the opposite of what I am saying.

Water does store and conduct heat extremely well, so this property can be exploited to use it as a working fluid. The nose heat exhanger can be designed to shed many more BTUs to the air since it doesn't need to have its design compromised for the ability to flow many CFM of air internally, and similarly, the intercooler unit does not have to be as large, since it is trying to shed heat to water instead of air. This can also result in less pressure drop through the intercooler.

Look at heater cores. Pass 20 degree air at high speed at high speed once through a 1" thick core and it gets heated to 150-160 degrees with 200 degree water. What do you think near-ambient water is going to do to hot ait that has to pass through 4-6 inches of cooler?

rslifkin wrote:

Appleseed wrote: This means that water takes a lot more energy to heat up. But once hot, it takes much longer to cool down.

Which is why the air/water setup gives more consistent intake temps. Even assuming that you don't get any extra cooling capacity from the more efficient heat exchanger design it allows, the consistency can sometimes be valued more than slightly better absolute performance under ideal conditions.

Which is great when you want the intake are to be warm (which is currently the case for OEMs, as we have been working on).

And stop assuming that an air-water heat exchanger is more efficient than a air-air- both can be great, both can be crappy- the design has evolved very nicely since the first ones have been introduced over 100 years ago.

Both systems dump the heat to the ambient air. There's the limit, done.

chiodos wrote: Alfa, I maybe getting terms wrong but heat sink absorbs heat from one thing and releases it to a cooling medium where heat exchanger transfers heat between two mediums. That's what I gleaned off my definition search please, if you would tell me what a heat sink is and why an intercooler is not one

I don't know why electronics use the word heat sink, but I do know in the mechanical world, heat sinks are used to retain heat and use it later. Heat exchangers are used to move heat from one place to another- which is what an intercooler is.

Boost_Crazy wrote: Why are you worried about heat soaking an intercooler in a stationary car?

If you spool the thing up to launch it, you'll have at least a second or 2 in boost while stopped and/or moving slowly when you first take off. Beyond that, it shouldn't be a concern for the most part.

rslifkin wrote:

Boost_Crazy wrote: Why are you worried about heat soaking an intercooler in a stationary car?

If you spool the thing up to launch it, you'll have at least a second or 2 in boost while stopped and/or moving slowly when you first take off. Beyond that, it shouldn't be a concern for the most part.

Which only can be done in an automatic. You can't spool a turbo in a manual while not moving. And if you are accelerating off the line, by the time there is air movement across the front of the car, you will finally have boost, and finally have enough compressed air where the temperature goes up. Nothing happens in an instant.

And that brings up another point, if you are going to spool a turbo at rest, then why would you not turn fans on at the same time? You are making an effort to launch the car, afterall.

Either way, a well designed system will work be it water or air.

alfadriver wrote: Which only can be done in an automatic. You can't spool a turbo in a manual while not moving. And that brings up another point, if you are going to spool a turbo at rest, then why would you not turn fans on at the same time? You are making an effort to launch the car, afterall.

2 step? That'll get some spool started if applied correctly... Provided you have a way to manually turn the fans on, you could definitely do that. But you might forget sometimes, or you might have not bothered adding a manual fan switch to the car, so that doesn't cover 100% of all cases.

In reply to rslifkin:

Screw 2 step, spin the bastard up with compressed gas.

So you are narrowing down your possible advantage example even more....

I'm not one to burn up a clutch just to spool the turbo... just sayin.

Either way, a well designed air-air or air-water-air system will work.

WOW Really Paul? wrote:

jere wrote: In reply to Boost_Crazy: It's "COULDN'T CARE LESS"! Think about it could care less makes no sense...

BTW, does your GM intercooler pump work? They wired them backwards from the factory on '04-5's...... *facepalms

It worked great at first with the wires reversed, it pumped all kinds of coolant past the leaking laminova seals

Its currently unplugged for winter. With the pump always running by design I assume there is some overcooling. I want it to make a difference in fuel economy but its probably marginalized by the factory cold air.

In reply to Knurled:

I never suggested that it stored the heat until game over. In fact, that is the opposite of what I am saying. Water does store and conduct heat extremely well, so this property can be exploited to use it as a working fluid. The nose heat exhanger can be designed to shed many more BTUs to the air since it doesn't need to have its design compromised for the ability to flow many CFM of air internally, and similarly, the intercooler unit does not have to be as large, since it is trying to shed heat to water instead of air. This can also result in less pressure drop through the intercooler. Look at heater cores. Pass 20 degree air at high speed at high speed once through a 1" thick core and it gets heated to 150-160 degrees with 200 degree water. What do you think near-ambient water is going to do to hot ait that has to pass through 4-6 inches of cooler?

You lost me there. I never suggested that you suggested, and never mentioned storing the heat. You talked about the efficiency of the front mounted heat exchanger. I just pointed out that you also needed to take the engine bay mounted heat exchanger into account. No one is doubting the ability of water to transfer heat. But all it's doing is moving that heat from one place to another, the air is still doing the actual cooling.

Your heater core example is interesting, but just makes my point again. The water is moving the heat from the engine to the heater core. Air flow through the core removes the heat and transfers it into the cabin. Very effectively, as you pointed out.

The stationary boost (and 70MPH CPU) examples were just to remind chiodos that he was forgetting airflow when comparing an I/C to a heat sink. Sure you can build boost on the line, I've owned a couple manual turbo cars with two steps. But it would take some serious effort and lack of mechanical empathy to be on the two step long enough to heat soak the I/C. And if you are using a two step, chances are the car will be moving quickly rather shortly. Never used mine in stop and go traffic, that would be interesting to say the least.

I dug out my copy of Maximum Boost last night, and re-read the intercooling chapter. If anything, I've given too much credit to the Air/Water. I assumed that the water was just to move the heat up front, and the front heat exchanger was capable of removing most of the added heat, and then it was returned to the reservoir. It turns out that according to the book, the system does rely on using the water as a heat sink, as it can't dissipate the heat fast enough and needs to buy some time between applications of boost. It mentioned sizing the reservoir so that the "used" water won't have time to complete a circuit during a 15 second run. It then needs time to recover. I did some further checking, and found that air/water is really tough to make work for extended periods of time, such as road racing. The large volume of water needed for the reservoir becomes prohibitive.

Recap- air/air and air/water do the same thing, both rely on air for the cooling. Air water just does it slower, longer to heat up, longer to cool down. It all depends on your packaging needs and use.

This has turned into an interesting discussion

Jumper K. Balls wrote: I just can't see how jamming all that stuff into an engine bay is easier or packages better than a front mount air/air

First off that radiator is much smaller. Then you don't have pipes having to be brought to the front of the car, you have smaller hoses which are also flexible. I posted a picture of what it looks like in a R33 skyline.

The thing you posted is even more economical on space.

If I wanted a pipe that isn't return flow I would have to cut a hole in my engine bay. The piping for this car is ODD to say the least.

What about e85 and no intercooler? I've heard some VERY good things, between the cooling capacity of the fuel and the detonation resistance...

E85 is more rare in the southwest than it is in the midwest otherwise I would consider it. I haven't seen it in any gas stations I use. I am aware of where to get it and it's not convienient. If I were to drive to LA or Phoenix and needed gas along the way I would be SOL.

For an autocross, I don't see a big advantage one way or another- most air coolers are sized really well, too.

What about advantages in response? The piping would probably be 1/4 the length if not less.

mad_machine wrote: I think the one thing missing in this conversation is routing. An air to water IC setup allows for a minimum of IC piping. Rather than having to shove pressurized air down to the bumper, then back up to the intake and into the engine, you can mount a small "box" of an Air/water intercooler inline with the intake.. or even as part of the intake as the supercharged Saturn Redlines did. Another plus, you can run multiple small radiators.. so like in the skyline, you can run a small one behind each foglight, or a long slender one infront of the main radiator. If you really needed to, a small fan can be used to help "force cool" the radiators

This is all basically why i'm looking at this.

I am not looking really for any advantage. Response or further cooling is just an added bonus. My questions on that was to make sure I wouldn't be losing anything. People have posted good reasons as to why air-air would be easier. Such as like leaking or possible pump failure for example.

One interesting thing is since the water lines take up way less space I would use one of the unused holes for intercooler piping for routing a cold air intake or something like that.

In reply to alfadriver:

So your saying that there are two entirely different meanings for the words heat sink? Also could you give me an example of an automotive heat sink? The only I can think of are say the finned differential covers on a newer f250 or armada/titan. But they do not function in the way you say an automotive heat sink works. I'm just trying to sort my own thinking out here.

I'm ignoring things said by some others that do not deserve any more fruitless arguing all I've got left to say is I too have read Corkey bells max boost years ago, but remember that book is actually dated by now and remember! Although in the end the air still cools the air, the internal designs of both heat exchangers, liquid intercoolers and even air to air intercoolers have changed massively over the past few years. What we need is some definitive numbers, DEFINITIONS, data, ect for the negatives and positives of both. Anyone with deep pockets want to take up that challenge? Haha

I'm saying I don't understand why electronics use the term heat sink for something that pretty much a heat exchanger. Perhaps it's because the medium that it warm to be cooled does not use a fluid material to start with.

The only heat sink I'm aware of are heat batteries that nobody uses. The fins on a diff are heat exchangers, just like the fins on a VW engine. As I see them. You are taking a hot gas (from the VW) or hot fluid (diff) and putting that into air. Maybe it's the lack of two flow streams going in and out that prevents them from being called heat exchangers.

But even by that more narrow definition, all intercoolers are heat exchangers- two paths of fluid in and out, one of the paths having the desired goal of being cooled down.

In reply to

more fruitless arguing

I see what you did there.

In reply to alfadriver:

Okay the two fluids exchanging make more sense to me

Boost_crazy I'll just leave it at, we're both hard headed and have our ideas, no sense in trying to convert the other to our ideals haha

In reply to alfadriver:

As I understand it, a heat sink as any object that draws heat away from another. Pretty much anything can be a heat sink. A heat exchanger is a type of heat sink that is designed to not just absorb the heat, but dissipate or transfer that heat.

The heat sinks in computers are actually heat exchangers, the term heat sink just stuck. They even separate them into passive (fins) and active (fan) heat exchangers.

A good example of a true heat sink is if you were welding or soldering and wanted to keep excess heat away from something, you would use a heat sink.

In reply to

Boost_crazy I'll just leave it at, we're both hard headed and have our ideas, no sense in trying to convert the other to our ideals haha

Yea, I pretty much had that figured out after your second post in this thread. I hope you find the answers that you are looking for.

Found some answers and then some, I do know I'll be liquid intercooling next go around, I'll take some measurements too.

In reply to chiodos:

What kind of jet ski are you getting?

Good one. go tell gm, ford, Bugatti, jaguar, Subaru, Toyota, Nissan, and everyone else their air to water intercoolers are dumb and they should have just used a big front mount instead hahaha

In reply to chiodos:

Sorry, I couldn't resist.

Seriously, what kind of car?