Why Ram-Air is BS, according to this guy...
06-07-2003, 06:28 PM
#46
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I have looked over RAM AIR setups before. After looking over them I have seem this, the way it kind of helps is because it brings cooler air in to engine due to the location of where it does it, right on top of the engine. There is less distance to travel in the engine to really get hot. About adding 1psi above absolute pressure is true but how much does that effect the power of the engine? Not much as far as get lots of power. Now if you wanted to add a supercharger or even a turbo, now the RAM AIR would really help to suck in much more oxygen quickly. That would be a good setup for a car if anyone would mod their car. I think that the RAM AIR does add HP without a question, but not as much as many people think. Many people talk like they are adding 50 hp with just that.
06-08-2003, 01:56 AM
#47
Race Director
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Mike1982:
<strong>I have looked over RAM AIR setups before. After looking over them I have seem this, the way it kind of helps is because it brings cooler air in to engine due to the location of where it does it, right on top of the engine. There is less distance to travel in the engine to really get hot. About adding 1psi above absolute pressure is true but how much does that effect the power of the engine? Not much as far as get lots of power. Now if you wanted to add a supercharger or even a turbo, now the RAM AIR would really help to suck in much more oxygen quickly. That would be a good setup for a car if anyone would mod their car. I think that the RAM AIR does add HP without a question, but not as much as many people think. Many people talk like they are adding 50 hp with just that.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Cold air intakes make only a very small percentage of their power increase from colder air. The power comes from the longer (and tuned if done right) intake tube. I know of a major aftermarket CAI company that determines the length of their intakes on the dyno by making small changes to the length.
Ram air would do very little for a forced induction system unless there is a restriction in the intake. A forced induction system will just suck in whatever air it needs.
<strong>I have looked over RAM AIR setups before. After looking over them I have seem this, the way it kind of helps is because it brings cooler air in to engine due to the location of where it does it, right on top of the engine. There is less distance to travel in the engine to really get hot. About adding 1psi above absolute pressure is true but how much does that effect the power of the engine? Not much as far as get lots of power. Now if you wanted to add a supercharger or even a turbo, now the RAM AIR would really help to suck in much more oxygen quickly. That would be a good setup for a car if anyone would mod their car. I think that the RAM AIR does add HP without a question, but not as much as many people think. Many people talk like they are adding 50 hp with just that.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Cold air intakes make only a very small percentage of their power increase from colder air. The power comes from the longer (and tuned if done right) intake tube. I know of a major aftermarket CAI company that determines the length of their intakes on the dyno by making small changes to the length.
Ram air would do very little for a forced induction system unless there is a restriction in the intake. A forced induction system will just suck in whatever air it needs.
06-08-2003, 02:22 AM
#48
Race Car
I figure its simply, if they market it, it may not be true. If they use it on the race track, it works. I don't need to look up Bernoulli's equation from the fluid dynamics book to know that most people if they can't dazzle you with brilliance they baffle you with b*llsh*t. I just remember the last time I checked, people still CHECK THEORY with REAL LIFE RESULTS and not the other way around no matter how much theory someone throws at you. I like someone's quote, when the green flag drops, the b*llsh*t stops.
06-08-2003, 07:30 AM
#49
Race Director
"It would be cool if we could see a data trace of a manifold pressure sensor mounted in the airbox overlaid with vehicle speed on a vehicle with a well designed ram air system."
Hard data, eh? Can't we just stick to marketing B.S. and 'sounds correct' conjecture?
One has to look at the factors that make ram-air work in existing applications. The motorcycles have a forward-facing scoop directly in front of and at the leading edge of the bodywork and the air goes through a sealed tract straight to the air-box.
Then look at scoop surface-area to engine-displacement. To get an equivalent system in a car, you'd have to have a scoop that's 1.0m wide by 0.5m tall being fed straight to an air-box that's hooked straight to the throttle-body (no bends allowed). And even then, you'd need to be going 170-180mph to generate the pressures necessary to make ram-air work.
Geo's right on about cold-air intakes. Above 20mph, I've measured identical temperatures inside a K&N filter that's placed directly behind the radiator as one that's behind the left headlight (both the same as outside ambient temperatures). In stop & go traffic, a Stg.1 MAF does have problems being behind the radiator when the secondary fans kicks on. I think this is actually more of a turbulence issue than heat.
Hard data, eh? Can't we just stick to marketing B.S. and 'sounds correct' conjecture?
One has to look at the factors that make ram-air work in existing applications. The motorcycles have a forward-facing scoop directly in front of and at the leading edge of the bodywork and the air goes through a sealed tract straight to the air-box.
Then look at scoop surface-area to engine-displacement. To get an equivalent system in a car, you'd have to have a scoop that's 1.0m wide by 0.5m tall being fed straight to an air-box that's hooked straight to the throttle-body (no bends allowed). And even then, you'd need to be going 170-180mph to generate the pressures necessary to make ram-air work.
Geo's right on about cold-air intakes. Above 20mph, I've measured identical temperatures inside a K&N filter that's placed directly behind the radiator as one that's behind the left headlight (both the same as outside ambient temperatures). In stop & go traffic, a Stg.1 MAF does have problems being behind the radiator when the secondary fans kicks on. I think this is actually more of a turbulence issue than heat.
06-08-2003, 10:25 AM
#50
Race Director
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Legoland951:
<strong>I figure its simply, if they market it, it may not be true. If they use it on the race track, it works. I don't need to look up Bernoulli's equation from the fluid dynamics book to know that most people if they can't dazzle you with brilliance they baffle you with b*llsh*t. I just remember the last time I checked, people still CHECK THEORY with REAL LIFE RESULTS and not the other way around no matter how much theory someone throws at you. I like someone's quote, when the green flag drops, the b*llsh*t stops.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Indeed, ram air works. However, there is a great deal of confusion about what ram air is. Most of what people call ram air is worthless. To have true ram air you must be able to generate positive pressure in the intake tract. This is very hard to do because the engine is sucking the air in at such a fast rate it's almost always under vacuum.
<strong>I figure its simply, if they market it, it may not be true. If they use it on the race track, it works. I don't need to look up Bernoulli's equation from the fluid dynamics book to know that most people if they can't dazzle you with brilliance they baffle you with b*llsh*t. I just remember the last time I checked, people still CHECK THEORY with REAL LIFE RESULTS and not the other way around no matter how much theory someone throws at you. I like someone's quote, when the green flag drops, the b*llsh*t stops.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Indeed, ram air works. However, there is a great deal of confusion about what ram air is. Most of what people call ram air is worthless. To have true ram air you must be able to generate positive pressure in the intake tract. This is very hard to do because the engine is sucking the air in at such a fast rate it's almost always under vacuum.
06-08-2003, 01:19 PM
#51
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Geo:
<strong>[QUOTE]Originally posted by Legoland951:
[qb] To have true ram air you must be able to generate positive pressure in the intake tract. This is very hard to do because the engine is sucking the air in at such a fast rate it's almost always under vacuum.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Sport Rider made the determination tha positive pressure wasn't achieved with most of the motorcycles until after 80 mph because of what you stated.
<strong>[QUOTE]Originally posted by Legoland951:
[qb] To have true ram air you must be able to generate positive pressure in the intake tract. This is very hard to do because the engine is sucking the air in at such a fast rate it's almost always under vacuum.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Sport Rider made the determination tha positive pressure wasn't achieved with most of the motorcycles until after 80 mph because of what you stated.
06-08-2003, 11:39 PM
#52
Burning Brakes
I read an article in a motorcycle magazine about a ram air setup. This was early on in the ram air craze of recent memory. They were designing a bike for a certain class, and the main restriction was that the bike couldn't put out over 130Hp to the rear wheel on a dyno before the race. The team of mechanics designed up a ram air system that would make the bike dyno to the right numbers but when out on the race track at speed they were absolutly killing the other bikes in straight-line speed. I'll try and dig it up so I can post more specific details. After reading it, I felt that ram air had atleast some benefits.
06-09-2003, 07:27 PM
#53
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Remember the simple truth: The same mod has different effects on different vehicles. Pontiac's mid 90's RamAir product was helpful on that vehicle mostly becuase the vehicle's stock intake was so restrictive. It wasn't a matter of ramming air down the intake, but allowing more air to flow through the intake. I had the same problem on a 96 Z28. Take a highly restricted intake vehicle and put ram air to it, and there will be some difference at higher speeds. I think it's been established that the NA 944 doesn't benefit from ram air but from true forced induction, which ram air is not.
06-09-2003, 11:22 PM
#54
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<a href="http://www.autospeed.com.au/A_0629/cms/article.html" target="_blank">http://www.autospeed.com.au/A_0629/cms/article.html</a>
Here is a series of articles, mostly detailing the negative effects of having a restrictive air intake and how to find them. But also the air intake designed to apply a positive pressure to the airbox, eventually sited in a somewhat different from usual place.
Here is a series of articles, mostly detailing the negative effects of having a restrictive air intake and how to find them. But also the air intake designed to apply a positive pressure to the airbox, eventually sited in a somewhat different from usual place.
06-10-2003, 02:38 AM
#55
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Most of the time you only notice a gain of 10 or more HP. This is why I stated that it was like 20-40. TRUST ME, it screamed compared to stock. I never ran it at a track, can't give any proof of the gains. I know that it did run about 30 degrees hotter on the highway, thus, probably going lean. I'm lucky it didn't blow up. I did run it slightly richer for a while until a curb killed my pickup tube.I was probably pushing 100hp on a good day, if that. It DID show improvement, I ran with a 5.0 Mustang from 80mph to about 120. Hmmmm, only 100hp, and a 5.0 is what? Then I guess eveyone is going to say the Mustang wasn't racing me. He was, I was on my way to school, I went to school with him. He was wondering what I had done to my turd to get it to run like that. I guess it could have been the cold air, but they don't work either, right?
06-10-2003, 03:05 AM
#56
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I think the Ram-Air effect does exist, but again, not until high speeds. A power gain may be present, but in order for the induction to take true effect, fuel/air ratios must be properly balanced at ALL times (eg. more air, more fuel) to compensate for the additional airflow.
I kinda see it that way because when i compare turbocharging and supercharging to ram-air, all 3 have similarities. They push more air into the motor. It's just that 2 of those 3 have significant power gains. I think there would only be a 2-3 more HP gain with ram air at high speeds....I could be wrong...
I kinda see it that way because when i compare turbocharging and supercharging to ram-air, all 3 have similarities. They push more air into the motor. It's just that 2 of those 3 have significant power gains. I think there would only be a 2-3 more HP gain with ram air at high speeds....I could be wrong...
06-10-2003, 03:11 AM
#57
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I've never understood why people had such a problem with this.
At automobile speeds air is incompressible.
I like to tell people to visualize a ram air cone or
what not in the water. Imagine moving it back in forth in the bath tub. Its fairly easy to see how the water just backs up and flows out the sides.
I found it interesting that the ram air requires a inverted cone. I did not know that, but I'm not sure I see why it has the stated effect.
At automobile speeds air is incompressible.
I like to tell people to visualize a ram air cone or
what not in the water. Imagine moving it back in forth in the bath tub. Its fairly easy to see how the water just backs up and flows out the sides.
I found it interesting that the ram air requires a inverted cone. I did not know that, but I'm not sure I see why it has the stated effect.
06-10-2003, 04:34 AM
#58
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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 Danno:
<strong>Then look at scoop surface-area to engine-displacement. To get an equivalent system in a car, you'd have to have a scoop that's 1.0m wide by 0.5m tall being fed straight to an air-box that's hooked straight to the throttle-body (no bends allowed). And even then, you'd need to be going 170-180mph to generate the pressures necessary to make ram-air work.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Displacement is not the only factor. In fact, peak HP numbers are probably the easiest way to compare airflow requirements. In an extremely simplifed ideal world, a 2 two stroke 500 cc engine running at 16,000 with a dynamic CR of 11:1 will consume a similar amount of air as a 2000 cc 4 stroke engine running 8,000 rpm with a dynamic CR of 11:1, and will make similar peak HP.
<strong>Then look at scoop surface-area to engine-displacement. To get an equivalent system in a car, you'd have to have a scoop that's 1.0m wide by 0.5m tall being fed straight to an air-box that's hooked straight to the throttle-body (no bends allowed). And even then, you'd need to be going 170-180mph to generate the pressures necessary to make ram-air work.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Displacement is not the only factor. In fact, peak HP numbers are probably the easiest way to compare airflow requirements. In an extremely simplifed ideal world, a 2 two stroke 500 cc engine running at 16,000 with a dynamic CR of 11:1 will consume a similar amount of air as a 2000 cc 4 stroke engine running 8,000 rpm with a dynamic CR of 11:1, and will make similar peak HP.
06-10-2003, 08:00 AM
#59
Race Director
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Steve Lavigne:
<strong>a 2 two stroke 500 cc engine running at 16,000 with a dynamic CR of 11:1...</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Dynamic CR?
No such thing. It's Internet BS. CR is a static measure. The rest is volumetric efficiency.
<strong>a 2 two stroke 500 cc engine running at 16,000 with a dynamic CR of 11:1...</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Dynamic CR?
No such thing. It's Internet BS. CR is a static measure. The rest is volumetric efficiency.
06-10-2003, 09:19 AM
#60
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I believe that the scoop on a trans am isn't ram air. I do believe that it does make a difference at HIGH speeds also. I don't think that you can compare a scoop on a trans am to a F1 car or a race bike. Like someone else said, look at the location of the scoops and how they feed the engine.
Here's the real question: What is the practical use of this on an every day street car? How often do you drive a trans am at speeds above 100mph in places where they sell them? I'm sure people do it, but why?
Here's the real question: What is the practical use of this on an every day street car? How often do you drive a trans am at speeds above 100mph in places where they sell them? I'm sure people do it, but why?