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I've always wondered about how cooling is possible given the design of the rear deck lid. We all know that there are only 2 primarily vents for air - 1. snorkel/airbox sealed intake and, 2. purge(scavenging) fan (which pulls air in when temp rise beyond 176F?)
And so, my question is... where is this higher pressure air being forced in? The lower part of the rear deck lid is still shut. When the spoiler lifts, are there other vents that air can get in or is it forced in at the gap?
Doc, if I pour a bag of ice into my Porsche's snorkel, will the air going into the throttle body be cooler regardless of air pressure? A poor man's cold air intake?
Ok, scratch that... it will melt and that could mean excess water in my airbox which could lead to ... oh my... lead to... eeekk... HYDROLOCK!!!!
lolz!
In the 1960s, Studebaker was struggling to stay in business. As a last resort, they reached out to Andy Granatelli for some kind of hype to get the flagging company selling Studes again. He came up with the idea of taking the Avanti(their most public offering) out to Bonneville flats and trying to break the speed record for production coupes. It was circa 1963-ish?
Studebaker strapped on a centrifugal supercharger, made by McCulloch(later nee Paxton), and they got bigger carb, different gears, etc to make up something called the R3/SC Avanti. Technically, one could go down to the Stude dealer and order one up, and it would arrive in a few months after the massaging by Granatelli. I think they sold all of 26 or something.
Anyway, back at the Salt Flats, in the middle of June, the hotted up Avanti was detonating like mad. They had avgas in it, they tricked around with the timing, jets, blower pulleys, and did everything they could to get that tool faster. The engine was running in the redline temp on each pass, and I guess they blew a couple engines along the way.
Finally, after all ideas for more speed were tossed around, one of the engineers got the wild idea of taking bags of cubed ice and filling the blower intake, the trasfer tube, and around the carb to get the intake air juuuuuuuuust a bit colder.
It worked! After they accounted for all the ice cooling, and turned the timing back a few deg they finally set some kind of land speed record, all the while the car was flowing like a 'ho on the rag all the way down the run.
While your theory's may be technically correct, the spoiler "up" does increased air pressure that does create increase air flow that does improve cooling. While something else could very well be at play here, the results are what they are.
There was an old saying that I have used many times in the old days of HotRodding cars and the quest for eventually setting a couple IHRA World Records by doing things that had never been before," If the results differ from the theory, believe the results and invent a new theory".
I'm sure that's all very interesting marketing.
Boyles law is not a 'theory' sir. Your statement is still incorrect.
In the 1960s, Studebaker was struggling to stay in business. As a last resort, they reached out to Andy Granatelli for some kind of hype to get the flagging company selling Studes again. He came up with the idea of taking the Avanti(their most public offering) out to Bonneville flats and trying to break the speed record for production coupes. It was circa 1963-ish?
Studebaker strapped on a centrifugal supercharger, made by McCulloch(later nee Paxton), and they got bigger carb, different gears, etc to make up something called the R3/SC Avanti. Technically, one could go down to the Stude dealer and order one up, and it would arrive in a few months after the massaging by Granatelli. I think they sold all of 26 or something.
Anyway, back at the Salt Flats, in the middle of June, the hotted up Avanti was detonating like mad. They had avgas in it, they tricked around with the timing, jets, blower pulleys, and did everything they could to get that tool faster. The engine was running in the redline temp on each pass, and I guess they blew a couple engines along the way.
Finally, after all ideas for more speed were tossed around, one of the engineers got the wild idea of taking bags of cubed ice and filling the blower intake, the trasfer tube, and around the carb to get the intake air juuuuuuuuust a bit colder.
It worked! After they accounted for all the ice cooling, and turned the timing back a few deg they finally set some kind of land speed record, all the while the car was flowing like a 'ho on the rag all the way down the run.
Truth - stranger than fiction sometimes.
Awww... day late, dollar short. So much for the patent idea. Guess it's back to work for me!
Next question, if I put melted crisco... oh .. never mind
A couple of questions from all of this spoiler talk.
There must be at least 30 different configurations of rear wing/spoilers for the 996 cars.
Has there ever been an actual study or comparison of the best results from all of those designs?
ie, down force, aerodynamics and fresh air intake?
I am sure such a study could create a spirited thread here.
Some of the comments here discuss different air temperature coming in to engine bay and CAI snorkle. I know Chrysler or Ford, I can't remember which, spent alot of money incorporating the a/c system into the supercharger to produce more horsepower.
As many threads here have been controversial to aftermarket intake systems inducting warm engine bay air, it is paramount to cool air and fuel to achieve the most horsepower. As one of the folks here mentioned IHRA records and another mentioned ice, back then the normal for a drag car was to utilize a cool can for the copper or aluminum fuel line to be coiled in and filled with ice, thus cooled.
Having this Carrera Wing, it seems to create enough down force to stabilize the car on the track, but I have nothing to compare it too. Not at all sure on the efficiency or air intake.
On a side note, when I installed the factory Porsche Aero/GT3 bumper, the installation instructions had bold print, Do not install on vehicle without a fixed rear wing
On a side note, when I installed the factory Porsche Aero/GT3 bumper, the installation instructions had bold print, Do not install on vehicle without a fixed rear wing
That's Porsche internal code for: "Let's see if we can get more money out of this sucker."
I agree, that would be a great study to read up on if it's conducted by a retable source.
As many threads here have been controversial to aftermarket intake systems inducting warm engine bay air, it is paramount to cool air and fuel to achieve the most horsepower. As one of the folks here mentioned IHRA records and another mentioned ice, back then the normal for a drag car was to utilize a cool can for the copper or aluminum fuel line to be coiled in and filled with ice, thus cooled.
Sigh,,,
The cooling of the fuel lines is to prevent fuel vaporization. Really, had nothing to do with the 'power' of the engine production aside from the engine shutting down if the fuel in the lines vaporized due to high temps, and very very low vapor pressure of the fuel concoction in use.
To be a complete *** again, one wants cool(cold) air because it's more dense, but hot fuel(just below vapor pressure) to atomize for optimal internal combustion.
The cooling of the fuel lines is to prevent fuel vaporization. Really, had nothing to do with the 'power' of the engine production aside from the engine shutting down if the fuel in the lines vaporized due to high temps, and very very low vapor pressure of the fuel concoction in use.
To be a complete *** again, one wants cool(cold) air because it's more dense, but hot fuel(just below vapor pressure) to atomize for optimal internal combustion.
and I'm done here.
Doc
You sound like part of the MSM, yes it was also used to prevent vapor lock, but last I knew, the carburetor sent the fuel into the intake manifold to be vaporized before the intake valve opened and the mixture of air and vaporized fuel would then be sucked into the cylinder when the piston was on the intake (down) stroke.
Manufacturers of intake manifolds went from cast iron to aluminum to keep things cooler, now we know there are all types of material used in intake manufacturing to keep the mixture cool.
Just saying
Just put your spoiler up and drive really fast backwards, that will scoop all kinds of air into the engine bay. Hey...just a suggestion. Just keep your snorkle covered with a baggie so it doesn't ingest something.
[QUOTE=b3freak;14490046]I've always wondered about how cooling is possible given the design of the rear deck lid. We all know that there are only 2 primarily vents for air - 1. snorkel/airbox sealed intake and, 2. purge(scavenging) fan (which pulls air in when temp rise beyond 176F?)
And so, my question is... where is this higher pressure air being forced in? The lower part of the rear deck lid is still shut. When the spoiler lifts, are there other vents that air can get in or is it forced in at the g
If you look at the picture in the post above, you can see the extended spoiler as it rises it also moves back some on the front edge uncovering the ducts to the engine compartment and engine air intake. The arrows show the high pressure area created underneath the louvered lid and is also aided by the bellows at the rear of the spoiler.
I have verified the temperatures with spoiler up and spoiler down and the fact is that the spoiler up promotes cooling of both the intake air and engine compartment air.
Geez, I get in more trouble than i want with my selection of words,"force" vs " pressure increase" and "theory " vs "law"
To explain more clearly what's happening, I'll give it a shot. While Boyles law is correct in that an increase in pressure DOES produce an increase in temperature, the other things at play here in my "theory" are the thermodynamics of convection and conduction that have a BIGGER effect of the air temperature.
The aerodynamics create a higher pressure that while DOES increase temperature also increase air flow which REDUCES temperature through convection and conduction. As air moves across all hot components IE the air ducts,air box, hoses,cables, the engine it's self, it removes heat and transfers it out the bottom of the car. the slight temperature increase due to pressure increase is overruled by the decrease in temperature by convection and conduction (ambient air flow).
Geez, I get in more trouble than i want with my selection of words,"force" vs " pressure increase" and "theory " vs "law"
To explain more clearly what's happening, I'll give it a shot. While Boyles law is correct in that an increase in pressure DOES produce an increase in temperature, the other things at play here in my "theory" are the thermodynamics of convection and conduction that have a BIGGER effect of the air temperature.
The aerodynamics create a higher pressure that while DOES increase temperature also increase air flow which REDUCES temperature through convection and conduction. As air moves across all hot components IE the air ducts,air box, hoses,cables, the engine it's self, it removes heat and transfers it out the bottom of the car. the slight temperature increase due to pressure increase is overruled by the decrease in temperature by convection and conduction (ambient air flow).
+1
I think your prior post were spot on, maybe just phrasing as increasing volume and rate , say like cfm, would have been easier to agree with. ie, the ram air or cowl put it into context well
09-21-2017, 04:26 PM
