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View Poll Results: Cold air vs Ram air
Cold Air 17 60.71%
Ram Air 11 39.29%
Voters: 28. You may not vote on this poll

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  #46 (permalink)  
Old 05-10-2009, 02:00 PM
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AP... how on earth are you getting 1% power increase from .072 psi? At best it would be .048% additional hp, and only at 61.7 mph where you don't need it.

On a 400 hp engine, that means an additional 0.2 hp. I think you got your decimals mixed up.

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  #47 (permalink)  
Old 05-10-2009, 02:25 PM
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Quote:
Originally Posted by barnym17
Are you sure the Holley book I have by Doug roe says percent not an absolute number.This supposedly comes from Holley engineering.
Yeah go w/that.
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  #48 (permalink)  
Old 05-10-2009, 06:21 PM
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.144/.072= about .5%, I used the .144 on accident for the previous 1% but this is the pressure at the front of the car,and like I noted the design of this one is REALLY primitive, basically a vacuum hose and a the top half of the plastic container used for a quart of oil. The real problem with this test is it does not list the before and after readings on the air duct. It notes that the vacuum is decreased by .144psi, but it does not show the before and after numbers, and this is where there is more of a direct corellation. taht.144 in the airbox is very significant IMO, how significant is not quite clear without the baseline numbers though. Nonetheless, instead of running a vacuum (as in the case of an airbox) you can run a slight positive pressure, and with a much cooler charge than even a "cold air" intake with a well designed system.

I'll have to scrounge up a camera and take pics of the one in my cutlass, its not optimal but its a hell of a lot better than a vacuum hose and a funnel.
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  #49 (permalink)  
Old 05-10-2009, 07:20 PM
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Curtis, methinks AP needs a remedial math course, along with some engineering. He doesn't understand the #'s he is using, nor how to manipulate the equations.

I agree, any gains purported to ram air are strictly cold air gains in reality.
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  #50 (permalink)  
Old 05-10-2009, 08:07 PM
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Quote:
Originally Posted by ericnova72
Curtis, methinks AP needs a remedial math course, along with some engineering. He doesn't understand the #'s he is using, nor how to manipulate the equations.

I agree, any gains purported to ram air are strictly cold air gains in reality.

I just had a brain fart. nonetheless, even a small amount of PSI makes a difference. And as of yet no one has commented that they have gone slower by using ram air. For the life of me I can't see how you can contest that its a detriment. Its not a huge gain but its there nonetheless.

Ideally this test should have been run with a very sensitive mass flow indicator right before the throttle plate, it would be the best easy indicator of improved air quality/volume IMO.

Its like running the tightest ring gap you can, it adds a small amount of power which to some isn't worth the hassle, and to others its silly not to considering all its takes is time.
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  #51 (permalink)  
Old 05-10-2009, 11:25 PM
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The point is not that Ram Air is bad. Its just that Ram Air doesn't add any benefits from pressurized air. It is a great addition since it ensures cold air, but 0.2 hp at highway speeds where it isn't needed doesn't interest me, nor do I consider it a "gain."

Even on a 400 hp, 150-mph bonneville top speed racer, it only adds about 0.7 hp, which wouldn't even add a tenth of a mph, but the additional drag always adds more restriction than the power increases. This has been proven a few thousand times by the fact that bonneville speed racers do everything they can to smoothly cover up their blowers and tunnel rams because that makes more speed. In fact, Car Craft or Hot Rod (not that I think they're an accurate resource) did those tests on their own cars. A tall cowl-induction hood that covered the air cleaner made 2-3 more mph instead of using a Hilborn-style scoop. If Ram Air actually worked, you would see all kinds of top-speed racers using them, but you don't. You see the exact opposite. They go to great lengths to make sure that every headlight gap is sealed up with duct tape, every mirror folded back, every gap that isn't absolutely necessary gets covered with duct tape. They can find a couple mph with those mods, so adding a 4" ram air duct would be like taking all that duct tape off in the hopes of gaining 0.7 hp. The net effect would be a loss of mph.

Harnessing the energy of the forward motion of a car in order to add more forward motion to the car falls squarely under the first law of physics. You can't get more than you give. Period. That means you're using the work created by the engine in a manner to cause it to create more work. Not gonna happen.

Last edited by curtis73; 05-10-2009 at 11:32 PM.
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  #52 (permalink)  
Old 05-11-2009, 06:10 AM
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Quote:
Originally Posted by curtis73
Harnessing the energy of the forward motion of a car in order to add more forward motion to the car falls squarely under the first law of physics. You can't get more than you give. Period. That means you're using the work created by the engine in a manner to cause it to create more work. Not gonna happen.

By your theory a blower will not work to increase power then... Seems like you missed a BIG something there.

also, a 1mph gain at 150MPH takes about 10hp for a typical car. And a LOT of speed racers do use ram air ducting, in fact I dare say most do.
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  #53 (permalink)  
Old 05-11-2009, 05:37 PM
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Boy AP, you really aren't getting it. To compare a blower to the minuscule air pressure obtained in a ram air system is ridiculous. ANY benefit you are attributing to ram effect is simply from the engine getting cooler than underhood air. Curtis has the knowledge and the empirical data and experience to prove it. You just don't want to admit you are wrong about this issue. It's all physics, and no one alive on this planet is exempt from these laws.
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Old 05-11-2009, 06:19 PM
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laminar flow

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Snake oil. Waste of money.
LOL I was making a funny The image is a piece for a scramjet.
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  #55 (permalink)  
Old 05-12-2009, 06:50 AM
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http://en.wikipedia.org/wiki/Ram-air_intake

That's a link that describes the basics of Ram air, and shows some factory cars, planes, and motorcycles that use it.
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  #56 (permalink)  
Old 05-12-2009, 07:29 AM
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Quote:
Originally Posted by ap72
By your theory a blower will not work to increase power then...
a blower isnt necessarily ram air... a blower is used with a supercharger and (correct me if im wrong) doesnt rely totally on motion like a ram air system does. at low speeds (like subsonic) ram air power increase is limited... extremely. ram air is, like curtis said, a myth. you have to be haulin major *** to get any signigicant power increase from ram air.
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Old 05-12-2009, 07:49 AM
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Despite what some may believe, there are still those who think it works and have data that backs it up.

It should be mentioned that "data" much like "statistics" are prone to manipulation.

I don't recall who is attributed to the saying, "There are lies, damn lies, and statistics", but I suspect they're right!

Sport Bike tested a batch of bikes and came up w/THIS.

Of course for every one that says yes, R/A works- there are one that says it doesn't.

Another lengthy but lively discussion on ram air is HERE.
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  #58 (permalink)  
Old 05-12-2009, 08:00 AM
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Quote:
Originally Posted by 83SILVRADO
a blower isnt necessarily ram air... a blower is used with a supercharger and (correct me if im wrong) doesnt rely totally on motion like a ram air system does. at low speeds (like subsonic) ram air power increase is limited... extremely. ram air is, like curtis said, a myth. you have to be haulin major *** to get any signigicant power increase from ram air.

a blower does rely on speed, the speed of its rotation which is driven by pulley diameters, gear reduction (in some cases), and crankshaft speed. It operates just the same as any other gear pump.

Ram air does rely on speed to provide the pressure differential, and a large enough opening to provide adequate flow. It has nothing to do with the speed of sound though. It is however dependant on the square of the velocity, meaning you will see dramatic increases as your speed increases (twice the speed is 4 times the pressure).
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Old 05-12-2009, 08:07 AM
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Quote:
Originally Posted by ap72
a blower does rely on speed, the speed of its rotation which is driven by pulley diameters, gear reduction (in some cases), and crankshaft speed. It operates just the same as any other gear pump.

Ram air does rely on speed to provide the pressure differential, and a large enough opening to provide adequate flow. It has nothing to do with the speed of sound though. It is however dependant on the square of the velocity, meaning you will see dramatic increases as your speed increases (twice the speed is 4 times the pressure).
I meant the speed of the car ******** and the speed of sound comment was reffering to that you have to be going the speed of sound to get any significant power increase. i was bein sarcastic. god i didnt think that i would have to spell this out for you but i swear to god its like talkin to a brick wall. Your like this on every post and it pisses me off.

Last edited by powerrodsmike; 05-16-2009 at 08:56 AM. Reason: Profanity. Please see: general board guidelines.
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Old 05-12-2009, 08:30 AM
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amen i love apples
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