Does RAM air work on cars or just bikes?

[fearlessphil]

Im new to cars, mostly had sports bikes an vans up till now and its got me thinking.

Nearly all sports bikes have some sort of RAM air forced induction but ive never seen it on a car?

Any reason for this, simple cocept on a bike i thought it would have been the same for cars?

[Barx325i]

it's all there, only on a bike they put a sign pointing out where the air goes in

I think for the power to weight / speed / drag factor of a bike - the air being forced in at 80+ mph does make a difference..

[HairyScreech]

Yes but as with bikes the ram effect is so small its not worth the effort, we worked out the actual pressure increase in uni once and its pathetic.

[DanThe]

Any idea what the figures are for pressures from differing intake areas screech?

[HairyScreech]

not off the top of my head, i think we had a .5m^2 opening in the calc and it was less than 5 psi benefit, might have been less than 1psi, either way you would be looking at turning the whole front of the car into a scoop for it to work.

[Barx325i]

on a bike, depending on the rev's and given the drag / weight, I guess they felt it worthy to try advertising the fact without the fear of being shot down and trade description liability.. Just

[HairyScreech]

pretty much, it was a gimic to sell bikes.

if one claims ram air for more power then you will buy that vs one that doesn't have it, its kind of why it has faded away a lot on bikes as well.

[Barx325i]

I thought due to the relative small capacity when these things reach high speeds an appropriately shaped duct would be pressurising the air sufficiently.. however these things would probably surpass the figures pretty quickly becuse they rev to 16k fairly quickly.. I guess in this case, only at the limit of speed where they're hanging on in top gear it may be of benefit, or alternatively comletely useless, as stated..

[HairyScreech]

thing is 200hp needs 200hp worth of air to combine with 200hp worth of fuel, the bike will have less losses but its not enough to make a huge difference unless you compare a huge american truck engine to a bike.

As you say, the faster you go the better it is, however you are talking over 100mph for a measurable difference and salt flat speeds to feel it.

[Barx325i]

marketable, but unattainable gains for most of the known polpulation seemingly

[appletree]

Any idea what the figures are for pressures from differing intake areas screech?

Sure there was somthing in one of James Mays programs and a somthing like 164mph it was equal to a 2bhp increase with direct airflow to the inlet.

Either way it was about a much use as an electric supercharger.

[appletree]

Any idea what the figures are for pressures from differing intake areas screech?

Sure there was somthing in one of James Mays programs and a somthing like 164mph it was equal to a 2bhp increase with direct airflow to the inlet.

Either way it was about a much use as an electric supercharger.

[HairyScreech]

^^ that makes me think my memory of less than 1hp at 100mph was correct then.

[Barx325i]

heresay to a point until proven I guess - As for bikes I'd say it's pretty relevent..

cars, nah nev's - whatevah man....fuck

[HairyScreech]

its even less relevant on bikes, they have about a 6" square inlet between the head lights, this intake has no where near enough area for the pressure infront of a bike to achieve anything.

Like i say we worked it out in a lecture a year or so back, i would have to find my notes to say anything for sure but the difference in air density was next to nothing, it actually surprised me how little an effect it would have.

a quick google of "ram air myth" will give lots of discussion on the topic, a good explanation of why a gain occurs is here
http://xlforum.net/vbportal/forums/arch ... 37320.html
However it is clear the effect is not "ram air" but more to do with the design constraints of a motorcycle.
lots of good discussion of this on speed talk as well as actual testing, benefits below 150mph come mainly from getting atmospheric air in.
http://speedtalk.com/forum/viewtopic.php?t=8810
http://www.speedtalk.com/forum/viewtopic.php?f=1&t=3003