Why Ram-Air is BS, according to this guy...
06-06-2003, 08:11 PM
#31
Three Wheelin'
Actually the ferrari uses an NACA duct, Which are qutie effective on smooth surfaces where you don't want to increase drag. Here is a <a href="http://www.aafo.com/racing/news/99/07-27-99.htm" target="_blank">article</a> where a modfied a mustangs belly scoop and replaced it with an NACA duct
06-06-2003, 08:26 PM
#32
Race Director
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by M Danger:
<strong>Actually the ferrari uses an NACA duct, Which are qutie effective on smooth surfaces where you don't want to increase drag. Here is a <a href="http://www.aafo.com/racing/news/99/07-27-99.htm" target="_blank">article</a> where a modfied a mustangs belly scoop and replaced it with an NACA duct</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Yep the NACA duct was designed for air plane use by predecsor of NASA back in the 1930's. At lot of physiscs and testing went into the duct so they work quite well. Remember the 931 has one of these on the hood to reduce under hood temps.
<strong>Actually the ferrari uses an NACA duct, Which are qutie effective on smooth surfaces where you don't want to increase drag. Here is a <a href="http://www.aafo.com/racing/news/99/07-27-99.htm" target="_blank">article</a> where a modfied a mustangs belly scoop and replaced it with an NACA duct</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Yep the NACA duct was designed for air plane use by predecsor of NASA back in the 1930's. At lot of physiscs and testing went into the duct so they work quite well. Remember the 931 has one of these on the hood to reduce under hood temps.
06-07-2003, 12:00 AM
#33
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It worked great on my 74 Nova with a inline 6. It killed most V-8s on the highway around 70mph and higher. It died when you let off the gas due to the lack of manifold vaccume. I used a 4"x4" industial vac attatchment and placed it under the front bumper in direct line of air flow. I'd say it was an honest 20-40hp, maybe more. I had it ducted to the factory air filter and otherwise completely stock. I thought it showed an improvement. Real world and "on paper" differ more times than not. This is my realworld experience.
06-07-2003, 01:22 AM
#34
Big thirst, Sore Thumbs
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Napoleon
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The idea is to get the scoop out of the laminar flow of the body.
See drag cars with big as scoops sticking out, or F-1 cars. Then you ar getting air pushing in, anything close to the body is going to spend to much time flowing over the intake.
As to Porsche et all doing it.
Er ah take a look at the 924GT did it or did it not have a ram air intake.
See drag cars with big as scoops sticking out, or F-1 cars. Then you ar getting air pushing in, anything close to the body is going to spend to much time flowing over the intake.
As to Porsche et all doing it.
Er ah take a look at the 924GT did it or did it not have a ram air intake.
06-07-2003, 01:46 AM
#35
Race Director
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by nine-44:
<strong>I used a 4"x4" industial vac attatchment and placed it under the front bumper in direct line of air flow. I'd say it was an honest 20-40hp, maybe more.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Horsepucky
<strong>I used a 4"x4" industial vac attatchment and placed it under the front bumper in direct line of air flow. I'd say it was an honest 20-40hp, maybe more.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Horsepucky
06-07-2003, 01:56 AM
#36
Nordschleife Master
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by SidViscous:
<strong>Er ah take a look at the 924GT did it or did it not have a ram air intake.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">It had a scoop for the intercooler...if thats what you're talking about??
<strong>Er ah take a look at the 924GT did it or did it not have a ram air intake.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">It had a scoop for the intercooler...if thats what you're talking about??
06-07-2003, 01:58 AM
#37
Hey Sid,
The 924GT had a hood scoop, but it was there to dump cool air on the intercooler (which was mounted over the valve cover) not into the intake.
The GTS and GTR had intercoolers mounted at the front like 951's. I don't think the scoop on those two iterations of the 937 does more than lower underhood temperature.
The 924GT had a hood scoop, but it was there to dump cool air on the intercooler (which was mounted over the valve cover) not into the intake.
The GTS and GTR had intercoolers mounted at the front like 951's. I don't think the scoop on those two iterations of the 937 does more than lower underhood temperature.
06-07-2003, 02:36 AM
#38
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by streckfu's951:
<strong>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+.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Exactly.. they were going 130mph on the bike.. .but the air was going slower at only 60mph. wouldn't the slower air mean higher pressure?
<strong>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+.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Exactly.. they were going 130mph on the bike.. .but the air was going slower at only 60mph. wouldn't the slower air mean higher pressure?
06-07-2003, 03:24 AM
#40
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This article looks correct for the math at first glance...been a while since I worked with flight controls. <a href="http://www.womanpilot.com/past%20issue%20pages/2000%20issues/jan%20feb%202000/airspeed.htm" target="_blank">Airspeed</a>
I love this statment at the bottom.
So, the next time a police officer asks if you know how fast you were going, you might respond by asking, "Do you mean indicated, calibrated, equivalent, true, ground speed, or Mach?" That will just about guarantee that you'll get a ticket.
I love this statment at the bottom.
So, the next time a police officer asks if you know how fast you were going, you might respond by asking, "Do you mean indicated, calibrated, equivalent, true, ground speed, or Mach?" That will just about guarantee that you'll get a ticket.
06-07-2003, 05:07 AM
#41
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by nine-44:
<strong>It worked great on my 74 Nova with a inline 6. It killed most V-8s on the highway around 70mph and higher. It died when you let off the gas due to the lack of manifold vaccume. I used a 4"x4" industial vac attatchment and placed it under the front bumper in direct line of air flow. I'd say it was an honest 20-40hp, maybe more. I had it ducted to the factory air filter and otherwise completely stock. I thought it showed an improvement. Real world and "on paper" differ more times than not. This is my realworld experience.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">You're joking, right? a '74 Nova would have (most likely) a 250cid I6, putting out about 100HP stock, and you got another 40HP out of ducting some air into carb?
<strong>It worked great on my 74 Nova with a inline 6. It killed most V-8s on the highway around 70mph and higher. It died when you let off the gas due to the lack of manifold vaccume. I used a 4"x4" industial vac attatchment and placed it under the front bumper in direct line of air flow. I'd say it was an honest 20-40hp, maybe more. I had it ducted to the factory air filter and otherwise completely stock. I thought it showed an improvement. Real world and "on paper" differ more times than not. This is my realworld experience.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">You're joking, right? a '74 Nova would have (most likely) a 250cid I6, putting out about 100HP stock, and you got another 40HP out of ducting some air into carb?
06-07-2003, 05:28 AM
#42
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As far as the concept of Ram-Air goes...It is much different then turbo-charging or applying a cold-air-intake system.
A true Ram-Air system actually has a scoop, which collects air passing over the car/motorcycle. This scoop is then connected to the air-box or throttle body via a sealed system. This creates a cool air intake with air being forced into the system. This is how horsepower increases, cooler air flowing through at a much quicker rate.
Now with a Ram-Air hood, this will not increase horsepower necessarily unless you modify the intake to adapt to the open port. Without this modification, it will simply apply more air into the engine bay causing a cooler running car.
This is how the 924 GT vented nose works. It is not a Ram-Air system simply because of the application of a scoop. Ram-Air involves an entirely different intake system.
A true Ram-Air system actually has a scoop, which collects air passing over the car/motorcycle. This scoop is then connected to the air-box or throttle body via a sealed system. This creates a cool air intake with air being forced into the system. This is how horsepower increases, cooler air flowing through at a much quicker rate.
Now with a Ram-Air hood, this will not increase horsepower necessarily unless you modify the intake to adapt to the open port. Without this modification, it will simply apply more air into the engine bay causing a cooler running car.
This is how the 924 GT vented nose works. It is not a Ram-Air system simply because of the application of a scoop. Ram-Air involves an entirely different intake system.
06-07-2003, 02:07 PM
#43
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by JasonECW:
<strong>"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.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I'm not 100% positive, but I think those ducts are used for cooling. Look at the ducts behind the doors on a 996TT. Those lead back to the intercoolers. They have nothing to do with Ram-Air, they just blast the intercoolers with cool air.
<strong>"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.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I'm not 100% positive, but I think those ducts are used for cooling. Look at the ducts behind the doors on a 996TT. Those lead back to the intercoolers. They have nothing to do with Ram-Air, they just blast the intercoolers with cool air.
06-07-2003, 03:55 PM
#44
Big thirst, Sore Thumbs
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Ahhhhh makes sense guys. Thanks for straightening me out.
Still think that while it wouldn't neccesarily increase HP it would effect throttle response. Since the problem (particurlarly with carberauted cars) is having enough air in the intake to feed the cylinders. So while it's not giving you anything like boost, it is filling the plenum more quickly than a pure vacum system.
Still think that while it wouldn't neccesarily increase HP it would effect throttle response. Since the problem (particurlarly with carberauted cars) is having enough air in the intake to feed the cylinders. So while it's not giving you anything like boost, it is filling the plenum more quickly than a pure vacum system.
06-07-2003, 04:17 PM
#45
Race Car
i think those big *** ram air intakes negate any benefit they have simply because the aerodynamic disruption is so great that it causes significant drag. besides, they look cheesy