Ram Air F/I

[SE-Man]

Hello,
I Know ram air isn't as big a as turboing and SCing cars, but I got into a discussion with a gearhead Ram Air Firebird owner. Suposivly around 60 miles per hour you can have up to 3-5psi of cold air forced into your engine. Thats the strenght of a low end turbo!! Mosly its depending on the Intake set up, Like my hood opening is 8"X2" and will be reduced to my intake size of 2 1/2" cusing a pressure increase with the forced air. So in theory If you were to make a top speed car, at arount 120MPH you could have close to 1 bar being forced into your engine. The down side is you'd not have any of the F/I from the light, only on the go.

So my question is, dose anyone no the PSI of resistence on a car at 60mph?

What do you think the HP increase at 60mph would be?

And what your thoughts on this subject?

[DavidOS]

i dont think it would act as forced induction on our cars.
Reason being is the car is still determining the air/fuel mixture to be injected and burned weather your WOT or just cruising at that speed.

Id say the air is colder but not 5psi forced.

[Mnemonic]

wonder if you could hook up some type of blower, get you like a belt driven blower, throw an UR underive pulley on, then with the addition of another pulley you should keep the same hp that you had originally, plus you have air now being litterally forced into your intake, rather than just having a forced air intake

[jordan69]

You know your theory is somewhat wrong there, since you are going from a large opening to a smaller opening, you have a larger pressure entering the ram hood at a lower velocity, when the air enters the smaller diameter intake pipe, the air turns from high pressure, low velocity, to low pressure, high velocity air, there is not a large amount of (boost) or pressure entering the engine, it is just air moving really fast. So the problem is that even though all this extra air is entering your engine, you can still only charge the cylinder up to atmospheric pressure, plus maybe a little, almost negligible extra because of the "ram air" effect, the high velocity air will just make it so that your cylinder is charged quicker with air, and thats about it, there is no real boost involved. See Bernoullis Theory.

<small>[ April 05, 2004, 05:51 PM: Message edited by: Kokaneedude ]</small>

[SE-Man]

hummm..... so all the pressure would be in the intake, and none in the engine, cuz theirs nothing to keep it from leaking out the way it came in.

[Nd4SpdSe]

Originally posted by Mnemonic:
wonder if you could hook up some type of blower, get you like a belt driven blower, throw an UR underive pulley on, then with the addition of another pulley you should keep the same hp that you had originally, plus you have air now being litterally forced into your intake, rather than just having a forced air intake

I hope your being sarcastic, but thats exactly how a supercharger works...

[Mnemonic]

Originally posted by Nd4SpdSe:

Originally posted by Mnemonic:
wonder if you could hook up some type of blower, get you like a belt driven blower, throw an UR underive pulley on, then with the addition of another pulley you should keep the same hp that you had originally, plus you have air now being litterally forced into your intake, rather than just having a forced air intake

I hope your being sarcastic, but thats exactly how a supercharger works...

[jordan69]

Thats right SE man, its just the the way this works, you have a large ram air scoop, and a small intake pipe, since the ram air scoop can build very little pressure just from driving fast, you have even less pressure in the intake to push in your engine, like i said, basically all you have is high velocity air entering our engine, not high pressure, so if you dont have the air pressure to over some the pressure inside the cylinder at bottom dead center, which is basically atmospheric, then you really get no "boost" out of it, all ram air will help you do is fill your cylinder faster at higher car speeds and it will make sure you arent sucking in hot engine air. If you actually had a turbo on the other hand, this would help to spool the turbo quicker since less load would be on the turbine to spin the compressor since high velocity air is entering the turbo compressor which it could change to high pressure itself.

[Nd4SpdSe]

Originally posted by Mnemonic:

[monty73741]

can i say one thing most stock turbo run @ 5psi...it tuners that increase the boost