Ram Air - Myth or Truth?

[vacooley]

try reading the article. Intake temperature has NOTHING to do with ram air, its like talking about spark plugs in connection with a diesel engine (for any that don't know, diesel don't have spark plugs, hence they have no relevance when talking about them). If you want more info PM me and I'll try and expand on it futher.

300... I understand what you are trying to say but air pressure and air temperature are DIRECTLY PHYSICALLY related. You absolutely cannot talk about one without specifying the other or you have no information.

Intake temperature affects air density, pressurization devices (possibly even ram air systems) affect air density... If air density was not affected neither would be important to a recip engine.

In moderate climates cold air intakes (and as the guy to tried to 'correct' was trying to say, a ram air is really just a version of a CAI) do not have huge affects. However, in very hot climates they have a huge impact to performance.

Your point that ram air systems don't make much (if any) performance gains is generally accurate. However, if they did not work you would not see them on drag cars, F1 cars and nearly every other type of race car that they are allowed on. No one would take the parasitic drag of the scoop if it did not help. Team Honda's enginneers, et al. are a little bit more up on this stuff that you or I.

Now, in bad weather they are not so good. Most of the factory ram air systems had some type of baffling to allow the water to seperate and drain off. (Submarining the car was not accounted for )

 

[300bhp/ton]

300... I understand what you are trying to say but air pressure and air temperature are DIRECTLY PHYSICALLY related. You absolutely cannot talk about one without specifying the other or you have no information.

Intake temperature affects air density, pressurization devices (possibly even ram air systems) affect air density... If air density was not affected neither would be important to a recip engine.

In moderate climates cold air intakes (and as the guy to tried to 'correct' was trying to say, a ram air is really just a version of a CAI) do not have huge affects. However, in very hot climates they have a huge impact to performance.

Your point that ram air systems don't make much (if any) performance gains is generally accurate. However, if they did not work you would not see them on drag cars, F1 cars and nearly every other type of race car that they are allowed on. No one would take the parasitic drag of the scoop if it did not help. Team Honda's enginneers, et al. are a little bit more up on this stuff that you or I.

Now, in bad weather they are not so good. Most of the factory ram air systems had some type of baffling to allow the water to seperate and drain off. (Submarining the car was not accounted for )

F1 cars and top fuelers will reach speeds where ram air can take place. ie an widening of the air intake at supsonic speeds will result in increased pressure.

To see this gain it appears that speeds of 150mph+ are needed, else the effect will be negligable.

 

[hotmustang331]

I have experemented with my custo ram air....I disconnected it and made it to where it wasnt sealed and it just blew on the intake. I kinda expected it to be faster since it was able to pull as much air as it needed and then was getting cool air blown on it.....I drove in and immadiatly noticed a pretty big difference down low in 1-2 and was like whoa!, its feels quite abit stronger and then I ran through the gears and when I hit 3rd, I could feel a pretty good difference (slower)...about like I said with the low speed difference (just reversed). So i decided to hook it back up, and everything was back to normal. IMO I can feel a difference, even though it seems i am only gaining ONE and a half HP at 75 LOL.

But anyways NICE explenation! You seem to know a LOT.

 

[Edbert]

So, in the case of a simple hood-scoop, one without an airbox or hoses connected to said scoop and carb (think 1965-1968 Shelbys), you are getting some benefit of cooler air in the engine compartment even at moderate speeds. While it wont show on a chassis dyno (even with a big fan) the difference in engine compartment ambient temperatures is worth SOMETHING.

But I couldn't agree more with the general premise that "Ram Air" is a merketing term for street vehicles.

 

[Jeepers!]

Ram Air

Bah! Humbug!