paulzy

iTrader: (1)

What's the price and performance difference between the two? Would it be worthwhile(moneywise)to get a water/air setup built for like 14-18psi of boost? What about all that pressure drop crap that everyone(including me, if I knew what how it works)keeps raving about?


[Modified by Slow_ass_4dr, 9:28 PM 7/31/2001]

bigTom

water to air is much more maintenace than air to air... by this i mean u have to refill whereever u hold the water with ice or whatnot... expecially in the summer it will get hot and it will basically defeat the purpose of the ic if u dont refill it... but it does do a nice job... u ever put aluminum in cold water... see how cold it gets... now imagine ice cold water running through it constanly

Ubermensch

water to air is more efficient (when the water is cold).

The water does heat up though since you've got a closed system.

In other words, if you're only running it for the track, water to air. If you're on the street most of the time you're better off with air to air.

The pressure drop across either is equal assuming the geometry of each intercooler is the same.

MDA

Hold up a second,

the water doesn't heat up... I've driven and booted around all day and the water does not get warm... stays ambient... especially when you run the water through a cooling core...

You do NOT need to change the water all the time... if you live in a cold region like me, u need to add some antifreeze in the winter... but that's about it..

The geometry of the core is much much smaller then air-air ... so the pressure drop is < 0.25 lbs... and the effieciency is much better..

The cost overall for the system is less then air-air but the install is more complex.

I don't understand why more people dont use these Air-Water IC's.. i can only assume that people like the bigass IC's in the front air dam.

DoctorBob

As I understand it, it has to do with fault tolerance (ref: Corky Bell's book). If you have a leak in your air-air system, it doesn't work as well: pressure loss, heat soak, etc. If you have a leak in your air-water system, you don't have an intercooler (after all the coolant drips out). Note - you don't necessarily have terminal failure at that point, you just aren't cooling your intake charge. Fix leak, refill, drive on, right?

You're right though: the little oil coolers that are used in place of the big air-air intercoolers aren't as visually stunning....

paulzy

iTrader: (1)

hey MDA....how long does a tank of water last you? What sized tank is it?

Ricehornet

he has a 4 gallon tank for a reseviour
If i remember his system is closed and runs thourgh a oilcooler when he isnt running ice, so in theory i would imagine the water lasts forever under ideal conditions, but in reality porbably a long *** time. long than you'd think.

Also, i would also imagine that when your NOT boosting the air-water IC, the air that is being drawn through will help cool it down along with the oil cooler.

Ubermensch

I was speaking from second hand knowledge on supras. I stand corrected. I'm sure it has a lot to do with the amount of boost and heat being generated.

I was thinking that the geometry would be smaller since you have much better efficiency. That's why I posted the assumption of same geometry to justify my comment.

I'm sure that's part of it, but i think most of it would be lack of knowledge. Luckily there are people like you letting us know how well it works. Maybe more people will get on them!

Ricehornet

if you figured how airflow area for a FMIC and a WAIC, you'll see that the flow area for the FMIC is rather less. Therefore, the pressure loss is MUCH less if you have the same size cores, but since you dont need the same size cores, you can use a smaller one and still net less pressure loss . Hence why on advantage is efficiency and compactness. This also allows you to use a low denisty turbulator design to help air move even better, cause the water heat transfer is better. Cept for the fact that the water is inside the IC and not the air


instead of ice why not put some coolant and water into the freezer and make it like -20 deg F. i know water and coolant doesnt transfer heat as well, but wont the >20 degs lower than ice water make up for it..just an idea, someone should try it with an IAT gauge

paulzy

iTrader: (1)

Hey MDA, how was your's setup? Can you list what I need for street driving and track day...what size is your oil cooler core? And all that other stuff....

The reason is that I don't want to use too much piping and take up too much room. So I figured that W/A IC is the way to go...I already lost my AC and p/s pump nad compressors, so I have all the room in the world, but I don't want to take up all that room up front in the bumper area....

dbman96

Ricehornet - better yet, put an ice / antifreeze mixture or even saltwater and ice mixture - that will bring it down to below the freezing point of water and its easier to buy bags of ice than to chill 4 gallons of antifreeze in your home freezer!

Ricehornet

COME ON PEOPLE get these tests done.....or are you gonna wait for me to do it?

Well adding ice, if i remember correctly, i thought the reason why iced tea gets cold when you add ice isnt because the ice makes the water cooler, but the water is melting the ice, so more cold water is added to the mix..so if you take that theory...putting ice in antifreeze will never bring the solution down to lower than the antifreeze or ~0C whichever is lower..perhasp im wrong cause i do recall when making icecream you put salt and ice, but the purpose of this is to get a liquid that is as cold as the ice, since ice can be as cold as it wants essentially. So, if you can make ice REALLY cold, and throw it into the coolant mixture, the coolant will mix with the ice, so it turns into a super cooled liquid. But, the problem is, the most ice that turns into a liquid, causes the coolant to be dilute, thus losing it's ability to depress the freezing pt, meaning, eventually your gonna get to an equilibrium. Where the coolant freezing pt is the same as the temp of the ice, so ice dont melt. But as you heat up the solution, it melts more ice, and inturns lowers the depression down even further, so "efficiency" is suffering through time. mmmm thermodynamics


I would stay away from salt water it's gonna corrode the pump/IC and leave icky residue....


If you live in a place that gets cold, imagine having your coolant mixture (with optimal ratio) optimal meaning jut enough so it doesnt freeze at the temp. X. Because too much antifreeze makes thermal conductivity less efficient, and too little makes it ice. so anyway, optimal ratio, in like 0F..thats COLD liquid going through the IC damn. Sure you may say it's the same as the FMIC in cold weather but dont forget the water/air IC is better at transfering heat.

DBMAN - come on dont tell me you dont have 4 gallons of antifreeze mixture that is in a proper ratio to optimize lowest temp and thermal transfer efficiency in your freezer at all times? what do you do when guest come over man!!



[Modified by Ricehornet, 1:39 AM 8/2/2001]

DoctorBob

[quote]Well adding ice, if i remember correctly, i thought the reason why iced tea gets cold when you add ice isnt because the ice makes the water cooler, but the water is melting the ice, so more cold water is added to the mix..[\quote]

Close. What's really going on is that the ice acts as a heat sink: there's somewhere for the heat to go. When the ice is all melted from all that heat, you're stuck, that's as cold as it's going to get. The "cold water from the ice" defines the final point of equilibrium, not how fast things get cold.

The best way to get a super cooled liquid is to have an externally powered heat sink (e.g., a chiller), plop it in the liquid and stir it. Keep stirring: as long as crystals don't form, the liquid will get colder and colder, possibly way below freezing without changing state. You'll sometimes see a quick chiller in high-end liquor stores for chilling mondo bottles of champagne and such.

Here's the interesting part: the air-water intercooler has a "stirrer": the pump. You'd have to do some experimentation but it should be possible to at least supercool the reservoir (water tank) right before a race (drop the chiller coils in the tank), run the pump to keep things from freezing right before the race and end up with better than 100% efficiency on your intercooler....

You can trust me, I'm a doctor.

MDA

Well all this talk about thermodynamics is making my head hurt.... Ahahah.... I'm sure there are ways to get things just a tad cooler... but let's face it... do we have the time and energy to investigate and test out these new methods?

My setup for the street & strip is such, 4 gallon tank (probably too big, but who cares, it's just more water to help suk out the heat), 2 gallons of antifreeze and the rest is filled with water...

Pony pump... nothing special about it other then it moves ALOT of water... one of the keys with a air-water IC (and even an Air-Air) is the continuous taking away of the heat... if the air or water is stagnent the IC doesn't work (besides the pressure drop causing heat loss, but lets not get overly technical here).... I forget the exact amount of water that pony pump pushes... but i think it's 40-60 Gallons / minute...

As was mentioned by Ricehornet, my system is a closed loop system without any leaks ... so it never needs filling... however if i hit the strip, i gots to take out some liquid to add ice... no biggie.

I have my pump hooked up to a pressure switch so it comes on when i hit 1 psi of boost... but i also have a bypass switch so i can run the pump whenever i want.

the little IC (2.5inch in and out ports) sits nicely just north of where the stock air box used to sit... it makes for a straight inline install.... right into the charge pipe b4 it hits the TB.

I also mentioned (in another thread) that i had 2 bypass valves that can take the little oil cooling core out of the loop... so the water goes right from the tank to the IC and back. This is handy when im running ice... the cooling core doesn't help when you're in an ice situation.

Unfurtunately i don't have a digital cam yet or else i'd take and post some pics... but it's on the way...


[Modified by MDA, 8:00 AM 8/2/2001]


[Modified by MDA, 8:03 AM 8/2/2001]

SW20 MR2

MDA,

If you want me to take some pics of your setup, lemme know, and I'll come by.

For those of you that haven't seen it (most of you), MDA's setup is really nice. The workmanship on his turbo setup was very impressive.

MDA

Yeah man, that would be cool... since i probably wont get this camera that hasn't shiped yet for a few weeks...

Have you seen it lately? Don't think so... it's all back together now after my little bender back in April..

Dunno if i mentioned it on the board here but some bonehead cut me off making a left turn from my right hand side and i smashed into him.... He was at fault and was charged.... but left my ride all messed up... fortunately it was repairable... for nothing less then a small fortune... But awell... **** happens.

Ricehornet

MDA - your pump is manually activated and or pressure activated eh. So if you leave it in "auto" it'll pump after 1psi, but when your cruising, isnt that when the heat is really being released from the system through the oil cooler core? Meaning if your not boosting, how is heat being transfered to the air(outside) if you dont turn it on. But i like that pressure activated idea too, doesnt run the pump when your not boosting, so it's like a "part-time IC" as Corky Bell stated.

Straight-line - good stuff, less pressure loss, delay and all that good stuff

The bypass valve to direct the flow around the oilcooler, thats manual right? cause it'll be pretty nice if you can do all of this inside the cockpit with a button.

MDA

Yeah normally it's left in auto mode... and when i know im going to go boosting like crazy ill hit the pump switch and leave it running....

The two bypass valves are manual and are under the hood... but those i dont switch all to often.... they are usually left in the position that lets the water flow through the cooling core.

paulzy

iTrader: (1)

Yeah man, try to get some pictures....