The Ram Air Effect Myth.

[Dom]

http://www.vetteguru.com/ramair/

Ram Air is just a another way to get air to the filter. The idea was that it acutally "rams" more air into the engine is just that, an idea. It does nothing more than make air available to the intake. It's a sort of like a glorified CAI.

[RedDragonV6]

I never did think ram air worked as good as people say it does.

[Danger Dude]

It does work once you get to some speed like on a highway up but in city driving wont help a bit. And on a 1/8 dragstrip the usefullness of it wont be there but on a 1/4 mile you would see some advantage but it will be small

[Dom]

Yea, 70 MPH. Kinda like the effectiness of a spoiler.

[stangin99]

Quote: Originally Posted by Dom Yea, 70 MPH. Kinda like the effectiness of a spoiler.

very few spoilers ever do anything at any speed.

[Danger Dude]

Quote: Originally Posted by stangin99 Quote: Originally Posted by Dom Yea, 70 MPH. Kinda like the effectiness of a spoiler. very few spoilers ever do anything at any speed.

you are referring to street cars I hope. Because on tracks spoilers do preform a function of supply down draft on cars!!!!

[Dom]

He better have. :|

[Ponycarman]

I'd suggest reading up on the Baumann effect, boundary layers and NACA's (Nasa's predecessor) investigations into ram air effects.

Ram air does have an effect IF the proper scoop design is used, none of which were used in the cited article. Of course sufficient road speed is needed and it's usually legal highway speeds or better.

Steve

[stangin99]

Quote: Originally Posted by Danger Dude Quote: Originally Posted by stangin99 Quote: Originally Posted by Dom Yea, 70 MPH. Kinda like the effectiness of a spoiler. very few spoilers ever do anything at any speed. you are referring to street cars I hope. Because on tracks spoilers do preform a function of supply down draft on cars!!!!

well duh.

slapping on any spoiler to any car wont do squat. You need a windtunnel and some adjustability to get anything from a spoiler.

[Dom]

Quote: IF the proper scoop design

Then the word money come into play.

[Danger Dude]

Quote: Originally Posted by stangin99 Quote: Originally Posted by Danger Dude Quote: Originally Posted by stangin99 Quote: Originally Posted by Dom Yea, 70 MPH. Kinda like the effectiness of a spoiler. very few spoilers ever do anything at any speed. you are referring to street cars I hope. Because on tracks spoilers do preform a function of supply down draft on cars!!!! well duh. slapping on any spoiler to any car wont do squat. You need a windtunnel and some adjustability to get anything from a spoiler.

Pleas do not DUH me :shock:

The fact is you dont need wind tunnel test with directional pressure sensitive tape and a few runs you can determine effectiveness. The need for adjustabbility is not necessary in a street car. Given the known limits of a car and the condition it will be driven you can make a permanent spoiler do all you want.

[Dom]

ding ding ding we have a winner!

:biglaugh:

[Ponycarman]

Quote: Originally Posted by Dom Quote: IF the proper scoop design Then the word money come into play.

Not at all, unless you want to spend money frivolously. Research a bit will save lots of money.

Believe it or not those big assed scoops used on drag cars are that way for a reason.

As air flows over the car the layer closest to the body, say about 1/2" thick, is very turbulent. So you have to raise the lowest point of the scoop opening above it.

You then form the rest of the scoop to funnel the high velocity, low pressure air into a convergent path that ends up feeding the intake higher pressure, lower velocity air. Exactly as the guru claimed needed doing. Problem is that none of the factory cars cited do that with thier scoops. That doesn't mean ram air doesn't work, it just means the designs cited are not useful in that application.

That is not to say the design is flawed, it's not, it the application that is wrong. The low drag ducted intakes used on the Firebird and such work great, on a fighter plane where the lowered drag of the ducted scoop far outweighs the loss of ram air effect, but are not appropriate on a low speed vehicle such as a car and I don't care how fast your Mustang is it isn't faster than a P51 Mustang .

Ram air works, if done right. The examples this guru used are not proof that ram air doesn't work, but rather that the particular examples chosen support a preformed theory of his.

Steve

[Dom]

So does the 03 Mach 1 Ram Air scoop work? What about the 03 GT scoop?

[Ponycarman]

The Mach 1 looks like it might work properly but might be a bit too small for much of an effect and it might not have the opening up high enough to clear that turbulent air layer, I haven't looked at it up close only pictures.

The GT's looks doubtful, it's lower opening of the scoop is right in the turbulent layer or air that hugs the body.

One other consideration is that you have to seal the scoop so that all the air flowing into it goes into the engine, the Mach 1 looks like it's sealed up properly. The GT's intake tract doesn't even look to be connected to the scoop at all, it appears to be purely cosmetic.

The problem with using a scoop big enough for ram air to work is that the drag goes up, same as the fighter plane example I mentioned. Pro stock racers don't care about that as the benefit of the scoop outweights the drag. In a street car that drag is there all the time, even when the scoop isn't "helping". Though the drag is less at slower speeds. So in a street car where CAFE standards have to be met you won't see a ram air scoop that is big enough to provide a substantial benefit unless you add one yourself.

So, while the Mach 1 scoop looks to be the right design, it's probably too small to provide much ram air effect.

Steve

[eagle05]

if pressure and volume is incressed even by a small amount at the throttle plate it would have to increase volumetric efficiey "do we have a spell checker" of the engine and as speed incressed pressure and volume should incress if it is scooping in the air as it should . and for spoilers my stock spoiler on my 79 camaro made it much more stable at 100 mph then my friends 79 camaro that didnt come with a spoiler.

[jimmy_beaner]

efficiency (that's about all I have to contribute to this thread)