M Danger

Well ramjets dont work well below 400mph.
But What Ram air does is collect the air in the direction you are moving. You dont think a 60mph wind is strong? Well you engine is sucking in air, having the intake open into the air stream is going to put a positive pressure, at the very lead of the intake and lower the vacuum inside the intake, AND since and engine is an airpump, the easier it is to get air in the more power you make.

Geo

Ram air does indeed work. I think Steve hit it right.

Most of what people call ram air is just horsepucky. Most people don't have a clue how it really works. For ram air to really work, you have to generate more than one atmosphere of pressure. Most of the places people put their "ram air" set-up is lower pressure. Remember that where air is flowing over a surface, the pressure is usually lower.

The base of the windshield is a high pressure area. It's not exactly what I'd call ram air, but it works.

Ram air, properly done, is part of what helps F1 engines and GP bike engines opperate at greater than 100% VE.

BTW, after the Senna accident the FIA tried very hard to slow cars down and one method was to require a hole in the air snorkle. This had a huge effect on engine performance.

kevin Dubois

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> their relativly Large CoF... the slipery-ist sportbike w/rider pushes about as much air per inch as your standard school bus. Vent some of that massive air into an airbox and you have an honest difference (there's data out there of bikes w/ ram air on a dyno running back to back with and without ram air making significantly different peak numbers). Difficult to dispute hard numbers. I'll try to dig some of that info up right now....
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">hehe funny stuff.. where are there mobile dynos? or was this dyno located in a wind tunnel?

if it is not, then that was the funniest quote because the ram air requires you to be MOVING at high speeds (according to the theory), not your wheels spinning at high speeds. i bet that the ram air on the motorcycles only reduces the restrictions on the intake, not forcing air into it.

essentially i am saying that ram air is totally useless on a dyno without a windtunnel too.

pcutt

Brian, can you clarify this?

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">
Or their relativly Large CoF... the slipery-ist sportbike w/rider pushes about as much air per inch as your standard school bus. Vent some of that massive air into an airbox and you have
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">- What's a CoF?

- What do you mean by "pushing as much air per inch as your standard school bus?"

Thanks,
Paul

triscadek

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> essentially i am saying that ram air is totally useless on a dyno without a windtunnel too. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">They dynoed the bikes with and without some sort of a force fed air setup.

What is interesting is that if you taper (arrow point) a brick at the front or rear, it has less drag if the taper is at the rear than the front.

streckfu's

About 5 years ago, Sport Rider magazines wanted to verify the effectiveness of Ram-Air. The used the Kawasaki and Suzuki motorcycles.

The used a Dyno and high velocity fan and connected a duct to the air inlet on the bike. They were only able to simulate up to 60 or 70 mph but found that it was already making a difference.

The biggest gains would be above 130mph which would benefit their race bikes. It has little use on the street but makes a huge difference on the back straight of Daytona at 180+.

Ken D

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Geo:
<strong>
The base of the windshield is a high pressure area. It's not exactly what I'd call ram air, but it works.
</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Hence the Cowl Induction hoods on certain Chevy muscle cars back in the day.

Travis - sflraver

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by qoncept944:
<strong>Without some numbers (plugged in to equations I don't know), where is his reasoning behind mach .5? Sounds like a number thrown out there to me.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Did you know that , statisticly speaking, 98 percent of people that quote statistics are just making them up.

Z-man

Three quick points:

1. CoF I believe stands for Coefficient of Friction. (Didn't read the article, though)

2. The 944S2 has a ram air type intake, but unlike the 'showy' hood scoops on top of muscle cars, it grabs air from underneath the car. I'm assuming air flow

3. You can't believe everything you read on the 'net!

-Z.

Geo

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Z-man:
<strong>2. The 944S2 has a ram air type intake, but unlike the 'showy' hood scoops on top of muscle cars, it grabs air from underneath the car. I'm assuming air flow </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">This is not ram air.

Z-man

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Geo:
<strong> </font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Z-man:
<strong>2. The 944S2 has a ram air type intake, but unlike the 'showy' hood scoops on top of muscle cars, it grabs air from underneath the car. I'm assuming air flow </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">This is not ram air.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">While it is not the conventional type ram air, it does have similar effects. That's why I said "ram air type" The air 'snorkel' below the air filter 'scoops in' air.

-Z.

The DareDevil

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Travis - sflraver:
<strong> </font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by qoncept944:
<strong>Without some numbers (plugged in to equations I don't know), where is his reasoning behind mach .5? Sounds like a number thrown out there to me.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Did you know that , statisticly speaking, 98 percent of people that quote statistics are just making them up.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica"><img border="0" alt="[ouch]" title="" src="graemlins/c.gif" /> <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />

Z-man

Ok: regarding stats:
Did you know that the weather man is 90% correct, 10% of the time!

-Z.

MachSchnell

"When it comes to Ram-Air, form does NOT follow function. If it worked so good, wouldn't Porsche, Ferrari, Lamborghini, etc. have picked it up by now?"

Um...have you ever looked at the 550/575 Maranello, and/or the Murcielago? Both these incorporate ram air, quite effectively. The 550/575 locates a duct on the hood, and the murcielago has those lovely vents that open at speed to force more air into the intakes. Not necessarily arguing that it works (pretty sure it does on the Murcielago, but not sure about the Ferraris) but they obviously try to incorporate the theory.

streckfu's

Your absolutely right about the ferraris, but I think the Lambo uses the retractable intakes for cooling.

Don't forget about Dodge and Plymouth using the hood scoops on the Cudas and Challengers.