boost temp.

Im about to have a turbo installed and im worried about detenation from heat. I know that intercoolers lower the temp. of boost thru the air that passes through the intercooler itself but, the problem is I live in phx, AZ where it's 110 degrees all day and i dont know if a front mount intercooler is sufficent enough to cool the boost. what i need to know is, isn't there a diffrent way to cool the boost? I'snt there a air to water cooler or something like that ?

the air to water cooler isnt really for street its for track because you put ice/water or just really cold water in it and it works great but after a few mins. the water heats up and melts all of the ice, that why its use on the track after your run you just refill it with ice/water again

Even if it is 100degrees outside, an intercooler will still work fairly well. The discharge from a 68% efficient turbo (about average, maybe a little low) on a 100degree day with 7 lbs of boost is close to 200 degrees. With a Good intercooler, the effeciency will be around 65-70%, this will lower your temps to about 133 degrees. Thats a considerable drop. Use an intercooler if your going to run 6-7 or more pounds of boost, if you use one with much lower than that you're kind of wasting your money. If you intercool 4 lbs of boost your going to be loosing a signifigant percentage of boost due to the pressure drop, it becomes not worth it anymore. Unless you buy a REALLY nice intercooler.
Air to water setups are more complicated to setup and are generally used in shorter runs, but I have seen a few in action on a daily driver. I think autospeed.com did an article on it. I think with the correct setup you're going to be fine, if you don't run lean and have a good tune then you don't have to worry about it.

Buzz1167
Jon N

as for lowering the temp of an intercooler, i know a few companies that cell Co2 tanks that will spray Co2 on the front of the intercooler, thus lowering the temp. i doubt you could use this all the time, but it may be possible to use it if the temp would get out of hand.

Yea but you cant drive around holding the spray button.
Buzz1167 is right....an intercooler does its job regardless of the outside air temp, it just helps more when its cooler

A few things.. I'm suprised no one has mentioned water/alcohol injection. Basically, you have a nozzle that sprays a mix of water and alcohol(rubbing alcohol works fine) into the intake, when water and alcohol atomize, they reduce charge temps by a huge ammount. It also has the effect of cleaning your combustion chambers, so it prevents carbon buildup. Carbon buildup will increase your compression ratio and hot spots in the chamber, making it more likely to detonate.
Also Buzz1167, your calculation for intercooler efficiency is wrong. 200* discharge temp is right, intercooler efficiency looks about right, but a 133* temperature drop is impossible. That would mean that your charge temps are now 67*, when the outside air temps are 100*. Intercooler efficiency isn't just compressor discharge temp * efficiency.. this is the formula:
(Tco - Tio)/(Tco - Ta) = E
Tco is temperature at the compressor outlet.
Tio is temperature after the intercooler.
Ta is ambient temperatures.
E is intercooler efficiency.
So rearranging the equation for temperture after intercooler you get:
-E(Tco - Ta) +Tco = Tio
so for your example, -.65(200-100) + 200 = Tio
-.65(100) + 200 = Tio
-65 + 200 = Tio
Tio = 135*

As for air to water, if you have a large enough water cooler out front, it should do better than a air-air setup, unless you drive your car hard. If you just occasionally floor it, air-water will work great. The more you push your car, the bigger the water cooler out front will have to be. Water transfers heat much much better than air. It requires a much smaller core compared to an air-air of the same efficiency.. smaller core means less pressure drop, less pressure drop means less compressor discharge boost for the same manifold boost, less compressor discharge means lower temps... so with the same intercooler efficiency and same manifold pressure, an air-water will have lower intake temps than an air-air. The problem is keeping the water cool. If you only have a small cooler out front, then yeah, air-water wont work so great. For my turbocharged v8, I'm going to be using an air-water and a big A/C condensor radiator(same size as my radiator except thinner.. 26"x19"x1" or something close to that..). I like air-water better mostly because when I do go to the track, I can fill it with ice water and get 100%+ intercooler efficiency.

the air to water cooler isnt really for street its for track because you put ice/water or just really cold water in it and it works great but after a few mins. the water heats up and melts all of the ice, that why its use on the track after your run you just refill it with ice/water again


Heard of a heat exchanger? Apparently not :rolleyes:

Also Buzz1167, your calculation for intercooler efficiency is wrong. 200* discharge temp is right, intercooler efficiency looks about right, but a 133* temperature drop is impossible. That would mean that your charge temps are now 67*, when the outside air temps are 100*. Intercooler efficiency isn't just compressor discharge temp * efficiency.. this is the formula:


Can you please read my post before typing that kind of stuff...

"this will lower your temps to about 133 degrees."

I never said It would drop by 133 degrees, I said it would drop TO 133degrees.
And if you didn't notice thats 2 degrees from what you had.

Water alcohol injection wasn't mentioned because this is a daily driver, filling up with water all the time is a pain, and the water will warm up to ambient and above while its in the engine compartment.
Also, an air to air intercooler will work just fine, theres no reason to goto a water injection system unless he's looking for lots of power, I think its more trouble than its worth. Plus, the question seemed geared towards the inability of an air to air intercooler to work, so I just said that it would still work fine and left it at that.

Edit:
This is the formula I use, I've had it in Excell for a while, and it took me a while to derive it and type it in from the lot of other equations I have, so here you go if you want it.

=((((((B26+460)*((B32+14.5)/14.5)^0.283)-460)-B26)/B34)+B26)-(((((((B26+460)*((B32+14.5)/14.5)^0.283)-460)-B26)/B34)+B26)-B28)*B36
Where:
B26 is Intake Temp (F)
B28 is Outside Temp (F)
B32 is Boost pressure
B34 is Compressor Eff. (Fractional)
B36 is Intercooler Eff. (Fractional)

The output is FINAL Temp, and of course it's not exact (like most of my equations) I didn't take into account for pressure drop, but usually thats not a big issue.

Buzz1167
Jon N

sorry my bad on the 133*, I missed that 'to'. No biggie. He coulda used the equation anyways.
The water in a water/alky injection system isn't supposed to be cold. It'll work well at ambient temps. It is the atomization/evaporation of the water and alcohol that causes a huge temperature drop. For example, when the air passes through a carbureator on a car, it experiences about a 40* drop in temperature, just from the gas evaporating into the air. Alcohol has much more of a cooling effect than gas.
Filling up isn't that bad... If you have a guage its no hassle at all. All it is is water and rubbing alcohol... Water injection will work about the same regardless of the temperatures outside, unlike an air-air or air-water intercooler. But it is still considered a 'band-aid', but if it fixes the problem, who cares.

I know water takes alot of energy to evaporate, and usually does it pretty slowly, wouldn't you have to be careful how much water you sprayed? If you got too much (whitch I think would be easy on a low boost car) it wouldn't vaporize and would just take up space and energy in the combustion chamber. Now alcohol on the other hand, that's a good thing no matter what, depending on what you use. I think methanol would be the best just becuase it evaporates really fast and it would act to enhance your octane. I think it has some ungodly octane rating like 110? But then again, water is almost free, methanol isn't.
The only problem I see with spraying anything on a daily driver is that, inorder to get the most power from this mod you would have to tune with it, and if you did that you would Need it to run correctly, thats what I wouldn't like.
The only problem with this philosophy is that I don't think you would need it in the first place, a FMIC does it's job pretty well.

Heres the bottom line, my approach to this situation would be to just get an intercooler and if it doesn't seem to be working as well as you like, then you can always throw a small injection system on top of it.

HTH
Buzz1167
Jon N

Yeah, very true. I wouldn't use water injection as a primary source of cooling, but maybe in a somewhat extreme situation such as his it might not be such a bad idea. On my car it is a track/sometimes strip deal. I have a air-water intercooler for primary, and if I hit the 'go' button, my timing retards, an extra 5psi of boost comes in and water injection turns on.. should be a blast.

Whered you get the air to water cooler? I know some people make them from air/air centers...
I think they are neat, but I haven't read much about them so I don't know how well they work. The water doesn't evaporate over time does it?

Buzz1167
Jon N

Well I kinda lied/misspoke.. its not built yet. I'm making my own, using two oil/trans coolers and some sheet metal. Its going to be built into the intake manifold(also being fabricated). I decided not to use air/air cores because: 1. I'm not good at welding aluminum and 2. I think the volume of the core inside an air-air is too much - the water will be moving too slow through it and by the time it gets to the other side it'll be warm, and not worth anything. Also the trans cooler is designed to be used with a liquid, I think it'll be more efficient. I'll post some pictures when its done, should be finished in a week or so.

Well I kinda lied/misspoke.. its not built yet. I'm making my own, using two oil/trans coolers and some sheet metal. Its going to be built into the intake manifold(also being fabricated). I decided not to use air/air cores because: 1. I'm not good at welding aluminum and 2. I think the volume of the core inside an air-air is too much - the water will be moving too slow through it and by the time it gets to the other side it'll be warm, and not worth anything. Also the trans cooler is designed to be used with a liquid, I think it'll be more efficient. I'll post some pictures when its done, should be finished in a week or so.

Best way to make an air/water intercooler is to use the air/air core and have the air flow through as it normally does, and then have the water run where the ambient air normally runs. This is basically how all race cars run their air/water coolers, and it's working for them. Oil coolers, for the most part, are grossly inefficient and do not make for a very good intercooling system. In 96 or 97 I built a TT camaro with my brother, and we tried to intercool it using trans coolers rigged into an intercooler. Even running 1 or 2 degree celcius ice water through the core we could barely meet the efficiency of our old air/air setup. If we tried to make 2 passes on the same tank of ice the IAT's would actually get to be higher than when we used the air/air cooler. We eventually scrapped the trans cooler idea, capped off the core of the air to air cooler and fed the ice water through there, and IAT's were substantially lower than with the old setup.

Cool, thanks for tellin me.. I don't know if I can fit that package under my hood anywhere, I'd at least have to radically change my design. If I were to use the reverse cooling using the water passing through the core and charge air going where cooling air used to, I could probably fit it in the same spot as before. With it built into the manifold, I cant figure a way to get it to be opposite. I'll let the ideas swirl around while I continue the fabrication of the other mani. I couple questions though, what size/how many/what style trans coolers did you use? I would be using two 11.5" x 11" x 3/4" coolers stacked on top of one another, so total size 11.5" x 11" x 1.5".. They're the plate style, not the tube and fin style. Plate is supposedly 33% more efficient.

Just take an air to air intercooler and have someone box up the cooling fins by welding two sheets aluminum across the fins. Then take two aluminum pipe couplers (www.Mcmastercarr.com is where I got mine.) and drill a hole in the upper part of one side of the intercooler where you had the aluminum plate welded and have the pipe coupler welded up over that hole, now you have a fitting. After that do the same thing on the other side except instead of drilling a hole in the upper part of the intercooler, drill it on the lower part of the intercooler. Drill the hole and have the pipe coupling welded on. After that go buy two hose barbs (I use 3/4 in hose) and screw them into the pipe couplers. After that, you need to find a pump ( I would reccomend at leasts 10 GPH). and wire it up. ( When you wire up the pump USE A RELAY!!!) and find a water tank that will fit into your trunk (5 GAL. MIN. is what I reccomend) plumb up your tank/pump/intercooler and you are good to go.

Now if you want to get fancy like I did, I incorperated a ball valve that will circulate my intercooler water through a heat exchanger for when I am on the street. I close the valve and I have Ice water in my tank and I am ready to go down the track, when I open the valve, I have my cooling water going through a heat exchanger dissapating the heat it adsorbs from my air charge. ( When the money/time permits, I am going to buy solenid accuated valves so all I have to do is wire them up and flip a switch.

Oh when you plumb up your intercooler, make sure that your supply hose is connected to the lower fitting on your intercooler, that way when the intercooler fills up is pushes all the air out the top return line.

Water has a CRAZY ammount of heat energy so if you have lets say a five gallon water resivor in the back and your intercooler holds a gallon, you have a 6 gallon system. Water will adsorb heat untill it reaches it's boiling point. after saying that go put six gallons of water under 400 degree heat and time how long it takes to boil. ALOT longer than just a few minuites (And thats at 400 degrees, you turbo will not produce that much heat)

P.S. If ANYONE starts to say "Oh but the weight will kill you blah blah blah..... BS!!!! :bs: The power you would gain vs. the weight you picked up would be more than worth it. Not to mention more intercooling which is just like having a bigger insurance policy.

Another thing to get in Alcohol injection, Im telling you it works!!! Without it, I can run 16 PSI of boost with it I can run 22 PSI with no deatonation. Here is all you need to know about alcohol injection.
http://home.att.net/~alkycontrol/page8.htm

Thanks guys, I think I'll do it like that. I think I've thought of a good way to do it. I'll sketch it and post it for you all to critique.