Intercooler water spray Science ® by http://www.CarPhoto.net
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Evolving Member
Joined: Sep 2003
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From: LA, CA, USA
Originally posted by QuantumEVO
I think you are the one that is most likely to be accused of flaming.
You have come on a bit brash and outspoken. Some of the guys are just commenting on their thoughts as to the effectiveness of this or that. I understand that it can be a bit frustrating, so I will give you my own thoughts. Let's chill a bit and talk about the whole waterspray system in a technical manner.
I have personally designed a waterspray system for WRX's (which are more in need of it than EVO's) and everyone seems quite happy with them. Waterspray is proven to yield improvements with an intercooler that is somewhere close to it's limit in terms of steady state heat exchange. That means that the primary heat exchange method (intake air to aluminum) is steady state and the secondary heat exchange method (aluminum to ambient air) is at it's full rate of exchange for the situation. This occurs once the aluminum finds a new, higher temperature. I have found that regardless of the water/alcohol mix, the nozzles and pump design are more crucial. If you attempt to use windshield washer nozzles, it will be sub-optimal in terms of evaporation. Ultimately you need it to evaporate because of the latent heat of vaporization. "Cutting" the water with alcohols assists in the vaporization process but reduces the net heat exchange in the process. That is why you must find a balance between using more water for better heat exchange and more alcohol to assist in vaporization. That being said, using more alcohol is somewhat of a bandaid to assist when the spray nozzles and pump pressure are not as good as they could be. A finer mist yields more liquid droplets and finer droplets. The ultimate effect is greater surface area between the airborn droplets and the air. Each droplet also has a lower total endothermic requirement to evaporate and make room for the next droplet. If you don't evaporate the droplet before it hits the intercooler, it will have a lesser chance of providing optimal heat exchange levels. In the process, I believe that the secondary heat exchange rate can be lessened a bit since you now effectively have an aluminum to water intercooler instead of aluminum to air. You are essentially drenching the IC in water. As this builds up, the possibility of the surface water evaporating declines rapidly and so does the effect of waterspray.
So ultimately, the first thing any EVO owner should do, IMHO, to improve waterspray is to use a better pump and finer nozzles. I sell such things in kit form for WRX and in individuall component form for DIY'ers. That being said, I am not trying to sell a kit (otherwise I would have just said; "Hey, I sell those!") but rather to help the EvoM guys understand waterspray systems a bit better.
Even with better pumps and nozzles, sometimes it still needs a bit of help in evaporating; that is where alcohol or something of that nature can help "fine tune" the setup of the waterspray. Finer mist is always better but the ratio between water and alcohol will depend heavily on the conditions. Ambient air temp, heat soak of the IC, steady state power output and heat loads and vehicle speed. There is no one setup that works the best with respect to ratios; it will depend on the conditions. A WRC EVO in Africa running massive amounts of torque out of a restricted stock turbo is running very high "duty cycles" of power compared to street machines. It is dumping heat into the intercooler at a drastic rate. On top of that, the ambient heat levels are very high and the air (in this example) is very dry. Dryer, hotter air will benefit more from waterspray and also be able to utilize a higher purity level (% water) for the W/S mix. If the vehicle speed starts to drop (in a few low speed corners) the IC is already so hot that it can assist with evaporating any excess water that started to soak onto the surface of the IC.
Well, anyways, that is my little technical comment section on waterspray.
On a street EVO, I personally recommend that once you upgrade your FMIC, you remove the IC spray system so the pod filter can pull air from the now gaping hole into the bumper reservoir as well as the underhood scoop (if it is still present). Ever wonder why there was an inlet on the side opposite the oil cooler? I belive this has a greater effect (steady state) than the waterspray system.
Peace,
Mark
www.Quantum-Racing.com
I think you are the one that is most likely to be accused of flaming.
You have come on a bit brash and outspoken. Some of the guys are just commenting on their thoughts as to the effectiveness of this or that. I understand that it can be a bit frustrating, so I will give you my own thoughts. Let's chill a bit and talk about the whole waterspray system in a technical manner.I have personally designed a waterspray system for WRX's (which are more in need of it than EVO's) and everyone seems quite happy with them. Waterspray is proven to yield improvements with an intercooler that is somewhere close to it's limit in terms of steady state heat exchange. That means that the primary heat exchange method (intake air to aluminum) is steady state and the secondary heat exchange method (aluminum to ambient air) is at it's full rate of exchange for the situation. This occurs once the aluminum finds a new, higher temperature. I have found that regardless of the water/alcohol mix, the nozzles and pump design are more crucial. If you attempt to use windshield washer nozzles, it will be sub-optimal in terms of evaporation. Ultimately you need it to evaporate because of the latent heat of vaporization. "Cutting" the water with alcohols assists in the vaporization process but reduces the net heat exchange in the process. That is why you must find a balance between using more water for better heat exchange and more alcohol to assist in vaporization. That being said, using more alcohol is somewhat of a bandaid to assist when the spray nozzles and pump pressure are not as good as they could be. A finer mist yields more liquid droplets and finer droplets. The ultimate effect is greater surface area between the airborn droplets and the air. Each droplet also has a lower total endothermic requirement to evaporate and make room for the next droplet. If you don't evaporate the droplet before it hits the intercooler, it will have a lesser chance of providing optimal heat exchange levels. In the process, I believe that the secondary heat exchange rate can be lessened a bit since you now effectively have an aluminum to water intercooler instead of aluminum to air. You are essentially drenching the IC in water. As this builds up, the possibility of the surface water evaporating declines rapidly and so does the effect of waterspray.
So ultimately, the first thing any EVO owner should do, IMHO, to improve waterspray is to use a better pump and finer nozzles. I sell such things in kit form for WRX and in individuall component form for DIY'ers. That being said, I am not trying to sell a kit (otherwise I would have just said; "Hey, I sell those!") but rather to help the EvoM guys understand waterspray systems a bit better.
Even with better pumps and nozzles, sometimes it still needs a bit of help in evaporating; that is where alcohol or something of that nature can help "fine tune" the setup of the waterspray. Finer mist is always better but the ratio between water and alcohol will depend heavily on the conditions. Ambient air temp, heat soak of the IC, steady state power output and heat loads and vehicle speed. There is no one setup that works the best with respect to ratios; it will depend on the conditions. A WRC EVO in Africa running massive amounts of torque out of a restricted stock turbo is running very high "duty cycles" of power compared to street machines. It is dumping heat into the intercooler at a drastic rate. On top of that, the ambient heat levels are very high and the air (in this example) is very dry. Dryer, hotter air will benefit more from waterspray and also be able to utilize a higher purity level (% water) for the W/S mix. If the vehicle speed starts to drop (in a few low speed corners) the IC is already so hot that it can assist with evaporating any excess water that started to soak onto the surface of the IC.
Well, anyways, that is my little technical comment section on waterspray.
On a street EVO, I personally recommend that once you upgrade your FMIC, you remove the IC spray system so the pod filter can pull air from the now gaping hole into the bumper reservoir as well as the underhood scoop (if it is still present). Ever wonder why there was an inlet on the side opposite the oil cooler?
I belive this has a greater effect (steady state) than the waterspray system.Peace,
Mark
www.Quantum-Racing.com
Originally posted by CarPhoto.net
Thats all I wanted. I already know my turbo/intercooler facts and history. Thank you quantum for the excellent advice. Is it possible I can goto home depo and buy the same misters used on plants. Thats what my friend did who is a WRX tech.
Thats all I wanted. I already know my turbo/intercooler facts and history. Thank you quantum for the excellent advice. Is it possible I can goto home depo and buy the same misters used on plants. Thats what my friend did who is a WRX tech.
The "home depot" stuff is suboptimal but I do know guys that use it. For a serious kit I would get something else. A good kit is pumping out much more pressure than a windshield washer pump and using finer mist nozzles. I have tested those "AZ Mist" nozzles at first , but didn't like the results. They clog easily, etc.My kit has built-in screens and check valves for every nozzle. The pump runs the system at 43 psi. If you try the pump on your windshield washer system it will shoot the water in a solid stream over the car and then blow the hoses off from the pressure.
Mark
www.Quantum-Racing.com
Evolved Member
Joined: Jan 2003
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You can buy similar nozzles from www.mcmaster.com . That is where I got most of the parts for my 100psi intercooler and radiator sprayer kit.
Go to catalog page 1883 at www.mcmaster.com , and there is a full array of "mist nozzles" for around $3 to $4 a piece. They work great, and havebuilt-in screens. A couple models have check valves built in, but if you have a solenoid in line and close, it isn't terribly important.
People use these for water injection, too.
Go to catalog page 1883 at www.mcmaster.com , and there is a full array of "mist nozzles" for around $3 to $4 a piece. They work great, and havebuilt-in screens. A couple models have check valves built in, but if you have a solenoid in line and close, it isn't terribly important.
People use these for water injection, too.
Interesting discussion. We definitely know that the intercooler works, and that making it cooler makes it work even better.
Part of the problem here relates to the magnitude of change from water spray. Even Mitsubishi claims only 2-3 hp, which is well within the normal variance (from my experience) between dyno runs, even with the same car on the same dyno. So it's going to be extremely hard to get any good data on water vs. washer fluid vs. alcohol, because even if it's 50% better, you'll only be talking about 1.5 hp difference.
Thanks for the link to the dyno chart with the N-Tercooler. I'm good buddies with Mr. David Buschur, and we talked about the possibility of N20 ingestion being the source of some of the horsepower gain. It's certainly possible that the engine is sucking in some nitrous. I haven't had the time or money to do a retest with CO2 in the tank, so I can't tell you for sure what difference that makes. On the other hand, the NX guys tell me they re-tested with an extension on the intake pipe that led to another room and they still got hp gains in the range of 50 hp. So it may very well be the cooling effect. Others that have used ice water air/water intercoolers or other super-chilled intercooling tell me it's easily good for 50 hp. Hey, I was shocked that it worked at all.
Back to the fluid question. I'm going to stick with the washer fluid (as specified in the owner's manual) because I don't have to worry about it when it gets down to freezing. The WRX STi owner's manual, on the other hand, says to use pure water, and to empty the tank when it gets very cold. If you were in the sun belt and didn't have to worry about freezing, I'd use pure water for the hightest heat capacity.
--Dan
Mach V
MachEVO.com
Part of the problem here relates to the magnitude of change from water spray. Even Mitsubishi claims only 2-3 hp, which is well within the normal variance (from my experience) between dyno runs, even with the same car on the same dyno. So it's going to be extremely hard to get any good data on water vs. washer fluid vs. alcohol, because even if it's 50% better, you'll only be talking about 1.5 hp difference.
Thanks for the link to the dyno chart with the N-Tercooler. I'm good buddies with Mr. David Buschur, and we talked about the possibility of N20 ingestion being the source of some of the horsepower gain. It's certainly possible that the engine is sucking in some nitrous. I haven't had the time or money to do a retest with CO2 in the tank, so I can't tell you for sure what difference that makes. On the other hand, the NX guys tell me they re-tested with an extension on the intake pipe that led to another room and they still got hp gains in the range of 50 hp. So it may very well be the cooling effect. Others that have used ice water air/water intercoolers or other super-chilled intercooling tell me it's easily good for 50 hp. Hey, I was shocked that it worked at all.
Back to the fluid question. I'm going to stick with the washer fluid (as specified in the owner's manual) because I don't have to worry about it when it gets down to freezing. The WRX STi owner's manual, on the other hand, says to use pure water, and to empty the tank when it gets very cold. If you were in the sun belt and didn't have to worry about freezing, I'd use pure water for the hightest heat capacity.
--Dan
Mach V
MachEVO.com
Sure, using icewater on an air/water intercooler or spraying something perhaps, but I still think the average joe is not going to see much gains with water spray on an FMIC equipped EVO. I've proven to myself that it provides huge benefits for heatsoaked Subarus, though.
Mark
www.Quantum-Racing.com
Mark
www.Quantum-Racing.com
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Joined: Sep 2003
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From: Indiana
I know, but I'm thinking in case the intercooler starts to get a bunch of snow and ice on it as you're traveling down a highway. Wouldn't that be very inefficient? So what if you put in the de-icer to help melt the ice off or snow? Or would it not freeze since it's so close to the engine. I just know that on the cars I have now, the front bumper will accumulate ice and snow after a little drive. It sure would suck to lose power because the intercooler is clogged.
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Joined: Nov 2003
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From: WC
Ultimatly the mist is trying to eliminate heat soak. Has anyone tried water whetter in their spray units (Added to the radiator, the manufacturer says it lowers temperatures by up to 8 degrees.).
It would be an expensive experiment, but how often do you try to wring every last hp out of your engine? That's rhetorical, please don't answer, lol.
It would be an expensive experiment, but how often do you try to wring every last hp out of your engine? That's rhetorical, please don't answer, lol.
Evolved Member
Joined: Jan 2003
Posts: 1,121
Likes: 1
Originally posted by Wrench
Ultimatly the mist is trying to eliminate heat soak. Has anyone tried water whetter in their spray units (Added to the radiator, the manufacturer says it lowers temperatures by up to 8 degrees.).
Ultimatly the mist is trying to eliminate heat soak. Has anyone tried water whetter in their spray units (Added to the radiator, the manufacturer says it lowers temperatures by up to 8 degrees.).
Originally posted by Showteg
I know, but I'm thinking in case the intercooler starts to get a bunch of snow and ice on it as you're traveling down a highway. Wouldn't that be very inefficient? So what if you put in the de-icer to help melt the ice off or snow? Or would it not freeze since it's so close to the engine. I just know that on the cars I have now, the front bumper will accumulate ice and snow after a little drive. It sure would suck to lose power because the intercooler is clogged.
I know, but I'm thinking in case the intercooler starts to get a bunch of snow and ice on it as you're traveling down a highway. Wouldn't that be very inefficient? So what if you put in the de-icer to help melt the ice off or snow? Or would it not freeze since it's so close to the engine. I just know that on the cars I have now, the front bumper will accumulate ice and snow after a little drive. It sure would suck to lose power because the intercooler is clogged.
Not put salt in the wound of a thread but the alcohol evaporates quicker so if you are continuously hitting the intercooler then it will remove just as much if not more heat. This is compared to just a spray of water, don't think I am equalling them.
Effectively, take a piece of hot metal and spray some water on it and it will cool x amount. Spray alcohol on it continously and it will cool even more. There is no problems with surface tension with alcohol like water so you can not flood the surface and inhibit airflow like you can with water. Jus an observation.
Originally posted by timzcat
the alcohol evaporates quicker so if you are continuously hitting the intercooler then it will remove just as much if not more heat. This is compared to just a spray of water, don't think I am equalling them.
Effectively, take a piece of hot metal and spray some water on it and it will cool x amount. Spray alcohol on it continously and it will cool even more. There is no problems with surface tension with alcohol like water so you can not flood the surface and inhibit airflow like you can with water. Jus an observation.
the alcohol evaporates quicker so if you are continuously hitting the intercooler then it will remove just as much if not more heat. This is compared to just a spray of water, don't think I am equalling them.
Effectively, take a piece of hot metal and spray some water on it and it will cool x amount. Spray alcohol on it continously and it will cool even more. There is no problems with surface tension with alcohol like water so you can not flood the surface and inhibit airflow like you can with water. Jus an observation.
In your example, spraying alcohol continously would also not evaporate; therefore water would be more effective. If your arguement is that the example compared dousing the hot surface with water versus a carefully controlled amount of alcohol, then you are simply reiterating the point that it really must be calibrated to the situation.
What I don't understand why everyone is stuck on buying alcohol for some reason over water when the pump pressure and nozzle design are more crucial. Everyone would rather keep buying alcohol to dump onto the IC rather than investing in proper equipment.
Mark
www.Quantum-Racing.com
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