NON-FI intercooler question.
Not happy with the stock radiator and will replace it soon with a racing unit. Eventually I want to Force feed it but that will be several years down the road.
The question is would an intercooler be worth while on a non-fi system? I know the underhood temps get pretty high and that would allow you to cool the air before it enters the engine. Just looking are doing the boost the long way. Slowly buying the parts and upgrading in stages.
No. Here's how/why an intercooler works:
Tubochargers and superchargers compress the intake air, raising the pressure above ambient. That's why you see boost labeled in PSI or pounds per square inch. When the intake air is compressed, the temperature also rises. This is evidence of the Ideal Gas Law, which says that as the pressure of a gas increases, so does the temperature.
A typical intercooler is an air-to-air heat exchanger, which brings the elevated temperature of the compressed intake air charge down closer to ambient temp by passing ambient air through the core and removing the heat (very simplified explanation). However, because it is an air-to-air heat exchanger, it cannot cool the intake charge down below ambient air temps even at 100% efficiency. It's physically impossible.
On a naturally aspirated engine, the air is uncompressed, so the temperature isn't elevated above ambient. Since an intercooler can't lower the temp below ambient, an intercooler can't decrease the temperature of the intake charge. The only thing an intercooler would do for a normally aspirated engine is add further restriciton in the intake tract, which is somehting you don't want.
Iain
"We don't stop playing because we grow old, we grow old because we stop playing." - George Bernard Shaw
Besides, then you'd have to pay royalties to TtT for the use of the Interfooler (TM) name...
Let me add that based on watching my post intercooler temp sensor in and out of boost, the intercooler only seems to remove heat while in boost. I can watch the temp rise to 130 F or more (likely the under hood temp at my intake) while cruising out of boost, but when I get on it and all of the hot compressed air is forced into the Intercooler, I watch the post intercooler temp rapidly drop to below 100 F.
Edit: Attached datalog showing air temp going in and out of boost.
Last edited by Titus; 08-11-2006 at 08:33 AM.
This is because hot things will cool down faster than cold things. Don't believe me? Take two ice cube trays and fill one with cold water and the other with hot, then put them in the freezer. The hot one will freeze before the cold one.
The increased cooling during boost is a result of the temperature differential (delta T) between the ambient air passing through and the commpressed air inside the intercooler. Also if you remember college algebra or chemistry, you will notice that according to Newton's Law of Cooling , hot items will start to cool rapidly and then start to plataou the closer they get to the ambient temperature.
'06 RSX Type-S NBP
Yes I know about thermodynamics. Thanks Titus for actually answering the question with valid data.
Also you need to take into account that as a compressed gas enters a larger volume it expands and cools in the process. So air from the turbo/Sc will cool more due to the expansion of the compressed gas in the intercooler.
No, those would go to me. :)Originally Posted by CraiginTX
BTW, Tim is late on his first royalty check...
This is complete and utter crap. It’s an old wive’s tale. Under controlled circumstances with no other variables, an object elevated to a higher temperature will never reach a lower target temperature faster than an object that is already closer to that target temperature.
Yes, the object heated to the higher initial temperature will have a higher initial rate of cooling. That’s because Object A (the hotter object) has a greater initial temperature differential. But the instantaneous rate of cooling is always dependent on the instantaneous temperature differential – cooling rate has no “memory” of what your initial temperature was.
Here is what this means: as Object A cools to the initial temperature of Object B (the cooler object), Object A will have the exact same cooling rate that Object B initially had. However, by this time Object B has already cooled to some lower temperature that Object A has not yet reached. Object A will never “catch up” with Object B, since the instantaneous rate of cooling that Object A experiences at any moment is exactly the same rate that Object B experienced when it was that temperature… and Object B was at that temperature before Object A ever got there.
Say it with me: instantaneous rate of cooling is dependent only on the temperature differential between the object and the environment at that particular moment. The initial temperature differential has absolutely no effect on the instantaneous cooling rate.
Iain
"We don't stop playing because we grow old, we grow old because we stop playing." - George Bernard Shaw
Actually, you need to take the pressure drop across the entire intake system into account. While there are typically small pressure losses over an intercooler, those overall losses are minimal (at least, they are if the intercooler and piping arrangement are properly sized and designed), and the cooling due to pressure drop across the intercooler volume is negligible at best.
There are a lot of misconceptions out there about charge air cooling. I spend all day every day designing – among other things – charge air cooling systems for large diesel engines used in mining equipment. I don’t profess to be an expert on the subject by any stretch of the imagination, but I do believe I have a better grasp on it than the average Joe.
Iain
"We don't stop playing because we grow old, we grow old because we stop playing." - George Bernard Shaw
Here's a couple of articles on hot water / cold water freezing:
This seemingly simple question continues to generate considerable controversy. Takamasa Takahashi, a physicist at St. Norbert College in De Pere, Wis., attempts a definitive answer:
"Cold water does not boil faster than hot water. The rate of heating of a liquid depends on the magnitude of the temperature difference between the liquid and its surroundings (the flame on the stove, for instance). As a result, cold water will be absorbing heat faster while it is still cold; once it gets up to the temperature of hot water, the heating rate slows down and from there it takes just as long to bring it to a boil as the water that was hot to begin with. Because it takes cold water some time to reach the temperature of hot water, cold water clearly takes longer to boil than hot water does. There may be some psychological effect at play; cold water starts boiling sooner than one might expect because of the aforementioned greater heat absorption rate when water is colder.
"To the first part of the question--'Does hot water freeze faster than cold water?'--the answer is 'Not usually, but possibly under certain conditions.' It takes 540 calories to vaporize one gram of water, whereas it takes 100 calories to bring one gram of liquid water from 0 degrees Celsius to 100 degrees C. When water is hotter than 80 degrees C, the rate of cooling by rapid vaporization is very high because each evaporating gram draws at least 540 calories from the water left behind. This is a very large amount of heat compared with the one calorie per Celsius degree that is drawn from each gram of water that cools by regular thermal conduction.
"It all depends on how fast the cooling occurs, and it turns out that hot water will not freeze before cold water but will freeze before lukewarm water. Water at 100 degrees C, for example, will freeze before water warmer than 60 degrees C but not before water cooler than 60 degrees C. This phenomenon is particularly evident when the surface area that cools by rapid evaporation is large compared with the amount of water involved, such as when you wash a car with hot water on a cold winter day. [For reference, look at Conceptual Physics, by Paul G. Hewitt (HarperCollins, 1993).]
"Another situation in which hot water may freeze faster is when a pan of cold water and a pan of hot water of equal mass are placed in a freezer compartment. There is the effect of evaporation mentioned above, and also the thermal contact with the freezer shelf will cool the bottom part of the body of water. If water is cold enough, close to four degrees C (the temperature at which water is densest), then near-freezing water at the bottom will rise to the top. Convection currents will continue until the entire body of water is 0 degrees C, at which point all the water finally freezes. If the water is initially hot, cooled water at the bottom is denser than the hot water at the top, so no convection will occur and the bottom part will start freezing while the top is still warm. This effect, combined with the evaporation effect, may make hot water freeze faster than cold water in some cases. In this case, of course, the freezer will have worked harder during the given amount of time, extracting more heat from hot water."
Robert Ehrlich of George Mason University, in Fairfax, Va., adds to some of the points made by Takahashi:
"There are two ways in which hot water could freeze faster than cold water. One way [described in Jearl Walker's book The Flying Circus of Physics (Wiley, 1975)] depends on the fact that hot water evaporates faster, so that if you started with equal masses of hot and cold water, there would soon be less of the hot water to freeze, and hence it would overtake the cold water and freeze first, because the lesser the mass, the shorter the freezing time. The other way it could happen (in the case of a flat-bottomed dish of water placed in a freezer) is if the hot water melts the ice under the bottom of the dish, leading to a better thermal contact when it refreezes."
Still feeling skeptical? Fred W. Decker, a meteorologist at Oregon State University in Corvallis, encourages readers to settle the question for themselves:</B>
"You can readily set up an experiment to learn which freezes earlier: water that is initially hot, or water that is initially cold. Use a given setting on an electric hot plate and clock the time between start and boiling for a given pot containing, say, one quart of water; first start with the water as cold as the tap will provide and then repeat it with the hottest water available from that tap. I'd wager the quart of water initially hot will come to a boil in much less time than the quart of water initially cold.
"The freezing experiment is harder to perform, because it ideally requires a walk-in cold storage chamber that is set to a temperature below freezing. Take into the chamber two quart-volume milk bottles filled with water, one from a hot tap and the other from a cold tap outside the chamber. Time them to freezing, and I would wager again that the initially colder water will freeze sooner than the initially hot water."
[We would add that, if you don't want to suffer in a walk-in freezer, you can conduct a reasonably good version of the above experiment in the freezer compartment of your refrigerator; just don't check the water too often-in which case it will never freeze-or too infrequently, in which case you may miss the moment when one container is frozen but not the other.] Decker concludes that "much folklore results from trying to answer such a question under conditions that do not make 'all other things equal,' which the foregoing experiments do.
So, was Mr. Wizard lying or not?
The ice test was on episode 10.
Thanks for the extra info Kiliwizz.
Last edited by Nexus Flux; 08-11-2006 at 11:49 AM.
'06 RSX Type-S NBP
Thefactor around here is through the roof.
Yes, quite the urinary contest between the teacher and the cut/paste crowd.The
RJ
Daily Driver: 2013 Club edition in Pearl White Mica
Lightness? What's that? I drive a PRHT!
I'll take the guy with the engineering degree...
That is the key. Good techniques will make all variables constant except the one experimental variable.
On the track, I am fearless.
If you were as slow as me, you wouldn't be afraid either.
1994 M Edition
CSP 67
I'm on Altain's side... The old hot ice trick keeps on coming back, that article is a good explanation of it all. It also shows that an intercooler can, indeed, cool the intake charge somewhat if it's drawn, say, from hot under-hood air. Now if you really want to get cold air in a NA engine, you might want to consider re-routing your air con....
All I know is I got 1100 dollars worth of useless metal in my car right now.....I see why it was named the "InterFOOLer." Royalty checks in the mail.
BTW...as a Science teacher I am very glad to see the intellectual dialogue concerning thermal conduction
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