Windchill does not apply to the damn air itself. The ambient temp of the colder air causes the surface it is passing over to drop in temperature. It does not cause the temp of the ambient air to drop. Hence the theory of riding on the hood of your car...? For you statement to be correct the air would have to chill the intake so much that the intake itself would cool the air even more...and that is impossible. Wind chill has absolutely no base for a discussion on ambient air temperature as it applies to how ram air works. We are talking about the stand alone value and true functionality of a ram air system. If the air were standing perfectly still then wind chill couldnt possibly affect the ambient air temp, because the intake (as well as the whole car) is what is actually moving through the air. Yes the wind temps will lower the surface temp of what it is blowing across...but how could that possibly further lower the ambient air temp? It cant. As far as thermodynamics and phyics not meaning jack ****...well, I guess you should start writing some books and correcting this terrible misinformation that is occuring in our educational institutions. The fact is that at such low speeds it is impossible for a tube design to compress air...or introduce more air into the engine. It can make more air available, but the engine cannot make use of it. The only way to take advantage of a greater availability of air is to either increase the air density...or to make more room in the engine for the air (ie bigger cylinders). Please try to argue with me on this...I beg you.
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'97 GT with 80mm C&L MAF, C<rue-Flow CAI, MAC 70mm TB, Superchip, 180 thermo, B&M Ripper, King Cobra Clutch, FRPP aluminum quad/adj cable, MAC O/R H pipe, MIL's, Flows, Granatelli Solid control arms, FRPP 4.10's, FRPP aluminum driveshaft, Fidanza aluminum flywheel, FRPP 9mm wires, TMD aluminum U/D pulleys, Steeda full length SFC's (welded in), and 17" polished aluminum Cobra wheels with Nitto 555 Extremes, Kenwood/Alpine sound. Waiting for install: PI intake.
It is not a matter of whether the air is being compressed, as is the case with a supercharger. You cannot compress air without an SC or Turbo. That is not the issue.
What I am stating is that having an external source of air will benefit the motor as you are tapping into a cooler source of air than what is available under the hood.
This WILL result in the intakes being cooler. This is important not in that the Intakes will now cool the air coming in even more, but that they will not HEAT the air coming in. Consider it an ounce of prevention. Anyone who has raced knows that the hotter you run, the slower you run.
I know that utilizing an external source of air will result in the Intake temperature dropping for a fact as I have tested this with a Raytech ST2L Infrared thermometer. I tested the temperatures of the Intakes at idle, driving without an external source of air and finally with an external source of air. I did this with my brother under various conditions of driving with him pulling over and me popping the hood and checking temperatures. The results were anywhere from 45*F to 85*F drop in temperature, depending on which component of the induction system checked. Tell me that there is a motor in the world that would not benefit from this.
Books and theory are fine and dandy, but even in high school science we are taught about the Scientific Method. That there is scientific theory which is accurate from a theoretical perspective and can proven in theory, but that this may not always be true if tested.
If it has to come from a book, though, in order for it to be considered true then I offer this from my University Physics text;
"...the scientific method involves 3 steps. 1. observation of the pertinent facts; 2. the invention of hypotheses or theories to order or explain these observations; 3. Testing of the hypotheses to see if their predictions are actually observed. It is a mistake, however, to think that scientists rigidly work through these 3 steps. Instead, a great deal of creativity and inspirations is involved. Even something as simple as "observing the pertinent facts" requires imagination, for scientists can never include everything in a description of what they observe. Hence scientists must make judgements about what is relevant in their observations."
And also;
"The "second law of thermodynamics" can be stated in several equivalent ways (1) heat flows spontaneously from a hot object to a cold one, but never the reverse; (2) there can be no %100 efficient
heat engine--that is, one that can change a given amount of heat completely into work......."
I think we have gotten off point here. There is no question that cooler air will benefit an engine. Nobody has ever argued that point. That is why there is no real performance difference between most CAI's and current "ram air" type setups. All you are doing is introducing cooler outside air to the engine, which is good, but its not rocket science and it certainly isnt some huge SOTP engine modification. The point of this thread was to debate the myth surrounding the functionality of ram air designs. Which is that they are not able to force more air into the engine...they are nothing more than a glorified CAI. I agree that you are going to cool surface temps of components under the hood. What I disagreed with was your statement that ambient air temp was affected by windchill. Lets steer the boat back on course folks.
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'97 GT with 80mm C&L MAF, C<rue-Flow CAI, MAC 70mm TB, Superchip, 180 thermo, B&M Ripper, King Cobra Clutch, FRPP aluminum quad/adj cable, MAC O/R H pipe, MIL's, Flows, Granatelli Solid control arms, FRPP 4.10's, FRPP aluminum driveshaft, Fidanza aluminum flywheel, FRPP 9mm wires, TMD aluminum U/D pulleys, Steeda full length SFC's (welded in), and 17" polished aluminum Cobra wheels with Nitto 555 Extremes, Kenwood/Alpine sound. Waiting for install: PI intake.
Yes it is true that they cannnot "Ram Air" into the motor, but to classify hood design with CAI's is also incorrect as a CAI can have only one function while a hood can have more than one. The author over generalizes the function, clumping everything into 2 categories; cold air or warm air.
A CAI can only bring in cooler air into the induction system that it draws in from the fenderwell. It is never directly in contact with the air stream and thus cannot benefit from the increased cooling available from external air when the vehicle is in motion.
Air is only at ambient temperature while the vehicle is at rest. When you begin to move, the temperature drops. I drove 1 mile at 30 mph with an auto thermometer hanging outside. Temperature dropped 10 *C.
A hood not only draws in cooler external air, but can also take advantage of the cooling effect offered by the motion of the vehicle as it is in direct contact with the air stream. A properly designed hood can also draw heat out from inside the engine bay. Remember the 69 up Shelby Mustang? To prevent heat buildup under the hood from warping the fiberglass, Shelby designed a hood with induction scoops and evacuation ports out the back.
Also, ambient air temperature IS affected by windchill when it is cold. That is why it is wind chill. In winter, you are given actual temperature obtained by eliminating exposure to the wind and the temperature after windchill.
Obviously the effect will not be the same as in winter and it is artificially created by the motion of the vehicle, but the result is the same, temperature of objects in the air stream will drop.
i am glad i signed up for these forums.
it's worth it's price (oh, wait, it was free) just for the entertainment value.
i hope you guys aren't actually getting mad at each other... we're all stang lovers here!
Dude,
Intelligent people do not have to be mad at each other to argue a point. We have a differing opinion on certain aspects of the ram air claim. We agree on the fact that air cannot actually be compressed, as would be the case with an SC or Turbo, but disagree on what the actual benefit would be.
I maintain that theory is irrelevant and a blanket statement like ram air is useless because it cannot compress air dismisses what may be the true benefit of ram air hoods . Empirical evidence, by way of actual testing is the only way to prove or disprove the benefit of any add on.
Air is only at ambient temperature while the vehicle is at rest. When you begin to move, the temperature drops. I drove 1 mile at 30 mph with an auto thermometer hanging outside. Temperature dropped 10 *C.
The tempature of the surface of thermometer dropped 10 degrees, the air was still the same temperature. All you were likely doing is reducing the amount of radiant heat retained by the thermometer and getting a true air temperature.
Your car will cool down as you move throw the air since your car will retain a portion of the radiant heat being directed at it. This however has zero effect on the ambient air temprature. Your car will cool down, which is good, but the air gathered by the induction system is always the same temperature. Scooping it off the hood or using it off the fenders makes no difference to the air temp as your car slices through it.
Putting scoops on your hood also creates an extra element of drag that would likely negate any "wind chill" benefit you'd see from scoops, if that was even possible.
Quote:
A hood not only draws in cooler external air, but can also take advantage of the cooling effect offered by the motion of the vehicle as it is in direct contact with the air stream. A properly designed hood can also draw heat out from inside the engine bay. Remember the 69 up Shelby Mustang? To prevent heat buildup under the hood from warping the fiberglass, Shelby designed a hood with induction scoops and evacuation ports out the back.
This was done because the heat of the engine was warping the hood, the air moving across the hood on both sides was more efficient at disipating the radiant heat the hood was absorbing, not because the "Wind Chill" factor of moving through the air caused the air temperature to decrease.
There is no doubt that moving air across an object will cause it to disipate heat. This does not translate into a wind chill that cause the temperature of the air moving across it to suddenly reduce its temperature, in fact quite the opposite. Conversely if the temperature of the air is higher than that of the surface it is moving across it will cause that surface to rise in temperature. Moving an object throught the air does not cause the air to change temperature, only the object, unless your talking about an extremely confined space and an object with a significant temperature difference, ie dropping a block of ice in a cooler, still this is not an instant sort of reaction, it will take some time for the air in the cooler to reduce, wind or no wind.
I can agree that a scoop may provide cooler air because it is a more direct route to the engine and there is nothing really to cause any other temp rises, like hot brakes or some sort of odd air circulation trap that is sucking air from the enigne compartment back up under the fender. It also avoids any issues with the induction pipe from the fender rising in temp from the exhaust or engine compartment. Whether the difference in performance gain is enough to justify the higher drag coefficient is highly debateable. This also does not mean you are reducing the temperature of the air, your only keeping it from rising enroute to the engine.
If this was a such a great way to improve vehicle performance you would see every race car in every circuit with a "Ram Air" setup. The only way this is worth it is if your feeding a high air volume power adding unit, like a blower.
There are mountains of "tests" of Ram Air Horsepower improvements. It is quite possible to show a HP gain using Ram Air, just like when using a good CAI. When you read these tests, or run these tests yourself, keep in mind the "control". Any good comparison test would take HP numbers from a stock induction system as the baseline. Then compare the CAI vs. Ram Air improvements from that baseline. I am quite certain your results between a quality CAI and Ram Air will be near equal. Not to mention most Ram Air proponents state the Ram Air effect really starts as you increase speed, and the HP improvements they claim during their sales pitch are estimated HP numbers. Estimates are just that, estimates. Unless you have someone that has recorded HP numbers while at speed, or while in a wind tunnel I would be highly suspect of any HP numbers from a vehicle "at speed". A properly sized high flow filter will allow more air flow than most any N/A vehicle could ever use.
Yes I studied physics, and fluid dynamics. I have also studied quite a bit more math than the average person so I tend to be able to see the theory behind much of the performance parts available. I also own a Mustang Corba that I drive the **** out of, I attend the occasional SCCA event and hit the drag strips from time to time too. I am quite well aware of the performance aspects of real life driving, street, track and strip. Its from this experience and my knowledge of physics and fluid dynamics that I can say with certainty that Ram Air has no net performance gain over a quality CAI.
I also know that if your using a type of FI that the performance gain from putting a scoop on your hood to feed that animal is in many (not all) cases worth the extra drag it creates.
OK, I understood the article (not all of the physiological aspects of fluid dynamics, mind you...just his explanation of why ram air doesn't work)...but is "Ram Air" and CAI the same basic principle?? In other words...did I just waste a few hundred bucks on the Densecharger system I ordered?? Are their "increased hp" claims complete horseshit??
Are their "increased hp" claims complete horseshit??
That is a very difficult question to answer. Increased HP compared to??? is a better question. Increased HP compared to bone stock, certainly. I cannot argue with that, the point I argue is the whether the RAM Air configurations gain enough HP over standard CAI systems to justify the extra drag, difficult to determine without a lot of testing. Personally, I dont think they are, but without any testing to speak of, I cannot prove it either way.
It also depends on the quality of the CAI system your comparing it to. A good quality CAI with plenty of cool fresh air and minimal bends in your induction tube, compared to a similar quality RAM Air system, I believe your HP difference would be very slight, if any at all. However, I have no evidence to prove such a claim, just my knowledge of the behavior of air, which is based on facts that have been proven time and again by people far more intelligent than me.
I hesitant to buy any product that uses actual numbers in their claim of HP gains. If you read them carefully... "HP gains of UP to 30 HP", which I read as in perfect situations, in a testing lab, with climate controlled areas, at least one vehicle showed a 30 HP gain using their product, it by no means says that my car will gain 30 HP using the same setup. Each vehicle will react quite differently to each setup. They may have used an 04 Cobra for the test, and went from 400 to 430 HP, not quite the same as taking a GT from 265 to 295 HP. Unless they state specifically what vehicle, what year and what engine options their HP gain tests relate to, you can never be certain what HP gain, if any, a mod will add to your vehicle, and that goes for any mod, not just CAI / RAM Air. Hell putting a good set of headers, and a top quality catback system on one of the new v-8 Lexus (dont remember which one, shoot me) will actually reduce your HP, due to the type of engine setup they use.
So before you buy ANY mod, its always a good idea to find out their baseline for the claim of HP gains, or at least try to find a speed shop in your area that has done some work with the mods your condidering.
Kulak has hit it on the head once again. Do your research in forums...they are usually a more honest evaluation than advertisers gains and even some car magazines. You will almost never get ideal conditions and usually never get the advertised gains. From everything I have read and tried the straight shooting CAI has always done better for me. The ram air kit I installed actually hurt my times. Go figure. That is why I am biased against them. I have tried both filter in the fender setups and stock type filter in the bay type CAI setups. I know what worked best for me. Right now I have the filter in the fender because we are fabbing a box for the engine bay. Then the filter goes right back in front of the mass air.
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'97 GT with 80mm C&L MAF, C<rue-Flow CAI, MAC 70mm TB, Superchip, 180 thermo, B&M Ripper, King Cobra Clutch, FRPP aluminum quad/adj cable, MAC O/R H pipe, MIL's, Flows, Granatelli Solid control arms, FRPP 4.10's, FRPP aluminum driveshaft, Fidanza aluminum flywheel, FRPP 9mm wires, TMD aluminum U/D pulleys, Steeda full length SFC's (welded in), and 17" polished aluminum Cobra wheels with Nitto 555 Extremes, Kenwood/Alpine sound. Waiting for install: PI intake.
A couple pages back, someone asked me to provide Dyno numbers before and after, and time slips before and after.
OK - the dyno comment is quite cute ... most dynoes I've seen do not allow the car to move - lol
My timeslips were VERY condusive .....
This is my OLD car, not my current one -
I had no less than 40 passes before the ram air I designed and several after. There were no other changes at all. No weight - no mods - no difference in temps - no elevation - ZIP.
I gained across the board 3/10ths and 1 mph. Those were my results. Several others reported back to me similar results doing exactly the only same thing.
This can get potificated for months (Which this thread has), but results do NOT lie.
I never installed it on my 01 because I am running Nitrous. Plus the BBK cold air won't allow me to run the same setup as on the 96.
How does the RAM Air differ from the comparison setup, and how do they both differ from stock?
and what are the performance gains from stock and what are the performance gains from a CAI (if any)?
I appreciate your efforts and I am not trying to debunk your data, I just want all the facts. Just saying you gained 3 tenths and 1 mph with RAM Air doesn't mean a whole lot unless you include what that gain was based on.
