Ram Air - Myth or Truth?
07-05-2005, 06:26 AM
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Ram Air - Myth or Truth?
Marketers just can't resist it. Ram air! The words themselves summon up images of rushing wild beasts, or of secret military aircraft operating on futuristic principles.
Unfortunately, on most perofrmance cars, ram-air is as functional as tail fins were on cars of the ’60s.
What is it? Ram air just means using a forward-facing air intake to gain some extra intake pressure. We have all, as children, felt the pressure of moving air on our hands when we held them out the window of the family car. When moving air is brought smoothly to rest, the energy of its motion is converted into pressure. Motorcycles went through a "ram-air" period in the early 1990s, during which street bikes were equipped with the forward-facing "rocket-launcher" engine air intakes seen on many road-racing machines.
While it's appealing to imagine the forward velocity of a car being converted into free supercharge, the actual air pressure gain is extremely small at normal speeds. For example, at 150 mph, the pressure gain when air is efficiently brought to rest is 2.75 percent. Because this is a dynamic effect, it is proportional to the square of the air velocity. At a more realizable automobile speed of 75 mph, the effect (again with 100 percent efficient conversion of velocity into pressure) will be only one-quarter as great — that is, just under seven-tenths of one percent.
In fact, velocity energy is not converted into pressure at 100 percent efficiency. A figure of 75 percent efficiency is usual, which reduces our notional ram-air gain at 75 mph to one-half of one percent.
Therefore, at normal speeds, ram air is a myth. However, something much more interesting lies behind it, ignored by the advertiser's busy pen. That something is airbox resonance.
In order to implement ram air, the carburetors or throttle-bodies of our engine must seal to an airbox whose volume is large enough that the intake cycle of one cylinder cannot pull its internal pressure down significantly. Box volume is typically 10-20 times the engine's displacement. Then the forward-facing air intake is connected to the box. When this assembly is tested on the dyno — even without an external fan to simulate the high-speed rush of air past the intake — it is discovered that the engine's torque curve is greatly altered, with new peaks and hollows.
Why? The answer is airbox resonance. If you hold the mouth of an empty bottle near your open mouth as you loudly hum scales, you find that at certain “hum frequencies” the bottle reinforces your humming, which becomes louder. What is happening is that the springy compressibility of the air in the bottle is bouncing the slug of air in the bottle's neck back and forth at a particular frequency — higher if the bottle is small, lower if it is larger. Your humming is driving a rapid plus-and-minus variation of the air pressure inside the bottle.
The same thing happens inside a resonant airbox. The volume of air in the box is the “spring” in this kind of oscillator. The mass of air in the box's intake pipe is what oscillates. The “humming” that drives the oscillation is the rapid succession of suction pulses at the carb or throttle-body intakes. If the volume of the airbox and the dimensions of the intake pipe(s) are correctly chosen, the airbox can be made to resonate very strongly, in step with the engine's suction pulses. The result, when this is done correctly, is that the engine takes air from the box only during the high-pressure part of its cycle, while the box refills from atmosphere through its intake between engine suction pulses. This produces a useful gain in torque.
Using this idea, motorcycle engines have been able to realize torque increases, in particular speed ranges, of 10-15 percent. In race engines, it is usual to tune the airbox to resonate at peak-power rpm to increase top speed. For production engines, it is often more useful to tune the box resonance to fill in what would otherwise be a flat-spot in the torque curve, resulting in smoother power and improved acceleration.
Early resonant airbox systems used long intake pipes that terminated in forward-facing intakes. More recent designs do not connect the ram-air pipe to the box at all, but terminate it near the airbox entry. The actual entry pipe is a short piece of tubing with bellmouths on both ends. This is done because (a) the potential gain from actual ram air is too small to worry about, and (b) it's easier to tune the airbox with a short tube.
Where vehicle speeds are very high, gains from ram air are significant. This was discovered by Rolls-Royce in the late 1920s as the company developed its R Schneider Trophy air racing engine. At speeds above 300 mph, it was noticed that the R’s fuel mixture leaned out enough to cause backfiring. When the mixture was corrected for ram-air pressure gain, the engineers realized they had a "free" source of power. At 350 mph the gain from ram air is almost 15 percent. Similar mixture correction is necessary when ram air is used on drag-race and Bonneville cars and bikes.
Intuition suggests that a forward-facing intake made in the form of a funnel, large end foremost, should somehow multiply the pressure of the air, resulting in a much larger pressure gain at the small end. Sadly, intuition is wrong. In order to convert velocity energy into pressure, the air has to be slowed down, and this requires a duct that widens rather than narrows. Next time you fly on a commercial airliner, note that its engine intakes widen as the airflow approaches the compressor face. Such widening passages are called diffusers, and they are universally used in the conversion of velocity into pressure.
Language often plays tricks on us — especially when language is used by product advertisers. "Ram air" sounds much more appealing than "resonant airbox." Nevertheless, it is airbox resonance that actually generates a significant power gain.
------------------------------------------------------------------
Cliffnotes:
-Ram Air a myth? = NO
-Does it work on a road car = NO
-At 150mhp there is next to no gain.
-Significant gains arn't seen until 300mph+
-The air box is the key, not the ducting.
-When buying a CAI/induction kit look for the one that uses air box resonance
Edit: Additional Reading
Intake temperature is a whole different ball game.
The simple rule is:
'Cool for power (maximum charge density), hot for economy (minimum charge density to reduce losses due to throttling).'
Although in many cars the under bonnent temperatures are no where near as bad as many people beleive. This refers to a 5.3 liter Jguar XJS V12. So a big engine in a small engine bay.
The under-bonnet air temperature at idle can easily get up around 70 C but the faster the car goes the lower the air temperature falls - simply because the radiator is passing its heat to a much larger quantity of air per second - so at 80 mph. the engine is breathing air at around 45 C. That's still a bit higher than the ideal but not nearly so bad as many people think. Obviously the standard arrangement helps to maximise economy in moderate speed urban cruise without compromising top end power too much.
In setups that duct cool air from outside. The power gains from such a system are almost certainly attributed to the filter, and less restritive intake (meaning quite simply a bigger opening), and a form of air box resonance coupled with a 'cool air intake' from outside the engine bay. Sadly even at very high speeds (well over 100mph) I doubt that it has any form of 'Ram Air' effect. If you reconfigured the system to take air from the inside of a wheel arch it would produce the same results as having the intake ducts at the front of the car. The source of the air, not the location of the ducts is the important factor.
Remember the only way to get a greater volume of air into the engine is to compress it. This is what turbo and superchargers do. An air intake scoop either on the front of a car or on the bonnet will not compress the air at any speed most people are likely to travel at.
Taking the airbox resonance theory futher with the intake manifold itself by optimising the length and entry profile into each of the tracts to better exploit induced harmonic resonances in the air as it flows towards the cylinder. Any tube containing air can be made to resonate at certain critical frequencies in the manner of an organ pipe. Such is the case with the inlet tracts of an engine and if the natural resonance frequencies can be matched to the engine speed then a mild supercharging effect can be induced. Get it wrong and the reverse will apply, resulting in a loss of performance.
Unfortunately, on most perofrmance cars, ram-air is as functional as tail fins were on cars of the ’60s.
What is it? Ram air just means using a forward-facing air intake to gain some extra intake pressure. We have all, as children, felt the pressure of moving air on our hands when we held them out the window of the family car. When moving air is brought smoothly to rest, the energy of its motion is converted into pressure. Motorcycles went through a "ram-air" period in the early 1990s, during which street bikes were equipped with the forward-facing "rocket-launcher" engine air intakes seen on many road-racing machines.
While it's appealing to imagine the forward velocity of a car being converted into free supercharge, the actual air pressure gain is extremely small at normal speeds. For example, at 150 mph, the pressure gain when air is efficiently brought to rest is 2.75 percent. Because this is a dynamic effect, it is proportional to the square of the air velocity. At a more realizable automobile speed of 75 mph, the effect (again with 100 percent efficient conversion of velocity into pressure) will be only one-quarter as great — that is, just under seven-tenths of one percent.
In fact, velocity energy is not converted into pressure at 100 percent efficiency. A figure of 75 percent efficiency is usual, which reduces our notional ram-air gain at 75 mph to one-half of one percent.
Therefore, at normal speeds, ram air is a myth. However, something much more interesting lies behind it, ignored by the advertiser's busy pen. That something is airbox resonance.
In order to implement ram air, the carburetors or throttle-bodies of our engine must seal to an airbox whose volume is large enough that the intake cycle of one cylinder cannot pull its internal pressure down significantly. Box volume is typically 10-20 times the engine's displacement. Then the forward-facing air intake is connected to the box. When this assembly is tested on the dyno — even without an external fan to simulate the high-speed rush of air past the intake — it is discovered that the engine's torque curve is greatly altered, with new peaks and hollows.
Why? The answer is airbox resonance. If you hold the mouth of an empty bottle near your open mouth as you loudly hum scales, you find that at certain “hum frequencies” the bottle reinforces your humming, which becomes louder. What is happening is that the springy compressibility of the air in the bottle is bouncing the slug of air in the bottle's neck back and forth at a particular frequency — higher if the bottle is small, lower if it is larger. Your humming is driving a rapid plus-and-minus variation of the air pressure inside the bottle.
The same thing happens inside a resonant airbox. The volume of air in the box is the “spring” in this kind of oscillator. The mass of air in the box's intake pipe is what oscillates. The “humming” that drives the oscillation is the rapid succession of suction pulses at the carb or throttle-body intakes. If the volume of the airbox and the dimensions of the intake pipe(s) are correctly chosen, the airbox can be made to resonate very strongly, in step with the engine's suction pulses. The result, when this is done correctly, is that the engine takes air from the box only during the high-pressure part of its cycle, while the box refills from atmosphere through its intake between engine suction pulses. This produces a useful gain in torque.
Using this idea, motorcycle engines have been able to realize torque increases, in particular speed ranges, of 10-15 percent. In race engines, it is usual to tune the airbox to resonate at peak-power rpm to increase top speed. For production engines, it is often more useful to tune the box resonance to fill in what would otherwise be a flat-spot in the torque curve, resulting in smoother power and improved acceleration.
Early resonant airbox systems used long intake pipes that terminated in forward-facing intakes. More recent designs do not connect the ram-air pipe to the box at all, but terminate it near the airbox entry. The actual entry pipe is a short piece of tubing with bellmouths on both ends. This is done because (a) the potential gain from actual ram air is too small to worry about, and (b) it's easier to tune the airbox with a short tube.
Where vehicle speeds are very high, gains from ram air are significant. This was discovered by Rolls-Royce in the late 1920s as the company developed its R Schneider Trophy air racing engine. At speeds above 300 mph, it was noticed that the R’s fuel mixture leaned out enough to cause backfiring. When the mixture was corrected for ram-air pressure gain, the engineers realized they had a "free" source of power. At 350 mph the gain from ram air is almost 15 percent. Similar mixture correction is necessary when ram air is used on drag-race and Bonneville cars and bikes.
Intuition suggests that a forward-facing intake made in the form of a funnel, large end foremost, should somehow multiply the pressure of the air, resulting in a much larger pressure gain at the small end. Sadly, intuition is wrong. In order to convert velocity energy into pressure, the air has to be slowed down, and this requires a duct that widens rather than narrows. Next time you fly on a commercial airliner, note that its engine intakes widen as the airflow approaches the compressor face. Such widening passages are called diffusers, and they are universally used in the conversion of velocity into pressure.
Language often plays tricks on us — especially when language is used by product advertisers. "Ram air" sounds much more appealing than "resonant airbox." Nevertheless, it is airbox resonance that actually generates a significant power gain.
------------------------------------------------------------------
Cliffnotes:
-Ram Air a myth? = NO
-Does it work on a road car = NO
-At 150mhp there is next to no gain.
-Significant gains arn't seen until 300mph+
-The air box is the key, not the ducting.
-When buying a CAI/induction kit look for the one that uses air box resonance
Edit: Additional Reading
Intake temperature is a whole different ball game.
The simple rule is:
'Cool for power (maximum charge density), hot for economy (minimum charge density to reduce losses due to throttling).'
Although in many cars the under bonnent temperatures are no where near as bad as many people beleive. This refers to a 5.3 liter Jguar XJS V12. So a big engine in a small engine bay.
The under-bonnet air temperature at idle can easily get up around 70 C but the faster the car goes the lower the air temperature falls - simply because the radiator is passing its heat to a much larger quantity of air per second - so at 80 mph. the engine is breathing air at around 45 C. That's still a bit higher than the ideal but not nearly so bad as many people think. Obviously the standard arrangement helps to maximise economy in moderate speed urban cruise without compromising top end power too much.
In setups that duct cool air from outside. The power gains from such a system are almost certainly attributed to the filter, and less restritive intake (meaning quite simply a bigger opening), and a form of air box resonance coupled with a 'cool air intake' from outside the engine bay. Sadly even at very high speeds (well over 100mph) I doubt that it has any form of 'Ram Air' effect. If you reconfigured the system to take air from the inside of a wheel arch it would produce the same results as having the intake ducts at the front of the car. The source of the air, not the location of the ducts is the important factor.
Remember the only way to get a greater volume of air into the engine is to compress it. This is what turbo and superchargers do. An air intake scoop either on the front of a car or on the bonnet will not compress the air at any speed most people are likely to travel at.
Taking the airbox resonance theory futher with the intake manifold itself by optimising the length and entry profile into each of the tracts to better exploit induced harmonic resonances in the air as it flows towards the cylinder. Any tube containing air can be made to resonate at certain critical frequencies in the manner of an organ pipe. Such is the case with the inlet tracts of an engine and if the natural resonance frequencies can be matched to the engine speed then a mild supercharging effect can be induced. Get it wrong and the reverse will apply, resulting in a loss of performance.
Last edited by 300bhp/ton; 07-05-2005 at 09:20 AM.
07-05-2005, 06:31 AM
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Team Owner
there is a long diatribe on this somewhere ....yeah its 
07-05-2005, 07:49 AM
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07-05-2005, 08:09 AM
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Le Mans Master
Nice write up, I actually mentioned this in a previous CAI thread, but I did not understand the concept enough to make a good write up about it. I have read many write ups for and against ram air by laymen and engineers on both sides of the argument. I have to tell you anyone that has run a vararam and seen the results has a real hard time disregarding the ram air claim simply because of the actual results and gains received from the product. Seeing is believing if you will. But with that said I try not to get to caught up in why it works, I simply know that this product does work and they do not mention resonance, rather they talk about ram air. The vararam intakes do start out small and empty into a larger box so that does go along with what you said about ram air.
To me it usually boils down to this. I know that ramming air into the intake works, (I have seen it on two of my cars), but I also realize some smart people come up with mathematical equations to disprove the phenomena exits. It is obvious to me they are wrong, probably similar to people who told the Wright brothers it was impossible to fly. I would guess they are probably leaving something out of their equations unknowingly. Maybe air box resonance is this missing component.
To me it usually boils down to this. I know that ramming air into the intake works, (I have seen it on two of my cars), but I also realize some smart people come up with mathematical equations to disprove the phenomena exits. It is obvious to me they are wrong, probably similar to people who told the Wright brothers it was impossible to fly. I would guess they are probably leaving something out of their equations unknowingly. Maybe air box resonance is this missing component.
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ElisTwoCents (11-05-2017)
07-05-2005, 08:32 AM
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St. Jude Donor '05-'08
Interesting. I always felt that at normal car speeds RAM AIR would not work, but COOL air getting to the engine would work. So I guess that RAM AIR systems are providing some benefit by allowing COOL air into the engine.
07-05-2005, 09:16 AM
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Originally Posted by Wicked Weasel
Interesting. I always felt that at normal car speeds RAM AIR would not work, but COOL air getting to the engine would work. So I guess that RAM AIR systems are providing some benefit by allowing COOL air into the engine.
Intake temperature is a whole different ball game.
The simple rule is:
'Cool for power (maximum charge density), hot for economy (minimum charge density to reduce losses due to throttling).'
Although in many cars the under bonnent temperatures are no where near as bad as many people beleive. This refers to a 5.3 liter Jguar XJS V12. So a big engine in a small engine bay.
The under-bonnet air temperature at idle can easily get up around 70 C but the faster the car goes the lower the air temperature falls - simply because the radiator is passing its heat to a much larger quantity of air per second - so at 80 mph. the engine is breathing air at around 45 C. That's still a bit higher than the ideal but not nearly so bad as many people think. Obviously the standard arrangement helps to maximise economy in moderate speed urban cruise without compromising top end power too much.
In setups that duct cool air from outside. The power gains from such a system are almost certainly attributed to the filter, and less restritive intake (meaning quite simply a bigger opening), and a form of air box resonance coupled with a 'cool air intake' from outside the engine bay. Sadly even at very high speeds (well over 100mph) I doubt that it has any form of 'Ram Air' effect. If you reconfigured the system to take air from the inside of a wheel arch it would produce the same results as having the intake ducts at the front of the car. The source of the air, not the location of the ducts is the important factor.
Remember the only way to get a greater volume of air into the engine is to compress it. This is what turbo and superchargers do. An air intake scoop either on the front of a car or on the bonnet will not compress the air at any speed most people are likely to travel at.
Taking the airbox resonance theory futher with the intake manifold itself by optimising the length and entry profile into each of the tracts to better exploit induced harmonic resonances in the air as it flows towards the cylinder. Any tube containing air can be made to resonate at certain critical frequencies in the manner of an organ pipe. Such is the case with the inlet tracts of an engine and if the natural resonance frequencies can be matched to the engine speed then a mild supercharging effect can be induced. Get it wrong and the reverse will apply, resulting in a loss of performance.
Last edited by 300bhp/ton; 07-05-2005 at 09:18 AM.
07-05-2005, 09:44 AM
#9
Le Mans Master
Well 300 you sound very knowledgeable but there have been members who replaced CAI's that are set up for ambient air & high flow filters with the vararam and received significant improvements. And from your explanation it would seem air box resonance is not something that could accidentally be hit on, in other words the box and intakes probably would have to be carefully designed. I don't think the vararam people claim any gains due to air box resonance, they sight cold air, high flow filter, and ram air.
So tell me why do you think the vararam out performs other CAI's. I am convinced by personal experience and other members posts that it does. Do you think maybe people are just mistaken, (possibly placebo effect), or is there something besides just cold air and high flow filter going on with this device? You sound like you know something about this subject so I would be interested in your opinion.
From my experience and others I have talked to I do not think you could simply draw air from the wheel well and match a CAI set up to draw air from the air stream. It would be very interesting to see this tested. I have seen this done with bottom breathers and they do not match the vararam's performance. Anyway that's my two cents.
Also I would like to tell you why I still post on CAI threads. I read these scientific explanations and I really do not want people who are looking for QTR mile ET improvements to be discouraged from purchasing a vararam based on these assumptions. The mathematics used probably is sound, I am sure you would not post for the fun of it. But in practical application I know these arguments do not hold up to the actual results.
So tell me why do you think the vararam out performs other CAI's. I am convinced by personal experience and other members posts that it does. Do you think maybe people are just mistaken, (possibly placebo effect), or is there something besides just cold air and high flow filter going on with this device? You sound like you know something about this subject so I would be interested in your opinion.
From my experience and others I have talked to I do not think you could simply draw air from the wheel well and match a CAI set up to draw air from the air stream. It would be very interesting to see this tested. I have seen this done with bottom breathers and they do not match the vararam's performance. Anyway that's my two cents.
Also I would like to tell you why I still post on CAI threads. I read these scientific explanations and I really do not want people who are looking for QTR mile ET improvements to be discouraged from purchasing a vararam based on these assumptions. The mathematics used probably is sound, I am sure you would not post
for the fun of it. But in practical application I know these arguments do not hold up to the actual results.
07-05-2005, 10:30 AM
#10
Personally, I think that the Vararam simply has fewer losses due to the air being at a slightly higher pressure than if it were simply an open element air filter; Zip-Tie, for instance. The Vararam pressure isn't enough to cause any ram effect, but enough to overcome losses that other intakes cannot.
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07-05-2005, 10:37 AM
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Originally Posted by shurite44
Well 300 you sound very knowledgeable but there have been members who replaced CAI's that are set up for ambient air & high flow filters with the vararam and received significant improvements. And from your explanation it would seem air box resonance is not something that could accidentally be hit on, in other words the box and intakes probably would have to be carefully designed. I don't think the vararam people claim any gains due to air box resonance, they sight cold air, high flow filter, and ram air.
So tell me why do you think the vararam out performs other CAI's. I am convinced by personal experience and other members posts that it does. Do you think maybe people are just mistaken, (possibly placebo effect), or is there something besides just cold air and high flow filter going on with this device? You sound like you know something about this subject so I would be interested in your opinion.
From my experience and others I have talked to I do not think you could simply draw air from the wheel well and match a CAI set up to draw air from the air stream. It would be very interesting to see this tested. I have seen this done with bottom breathers and they do not match the vararam's performance. Anyway that's my two cents.
Also I would like to tell you why I still post on CAI threads. I read these scientific explanations and I really do not want people who are looking for QTR mile ET improvements to be discouraged from purchasing a vararam based on these assumptions. The mathematics used probably is sound, I am sure you would not post for the fun of it. But in practical application I know these arguments do not hold up to the actual results.
So tell me why do you think the vararam out performs other CAI's. I am convinced by personal experience and other members posts that it does. Do you think maybe people are just mistaken, (possibly placebo effect), or is there something besides just cold air and high flow filter going on with this device? You sound like you know something about this subject so I would be interested in your opinion.
From my experience and others I have talked to I do not think you could simply draw air from the wheel well and match a CAI set up to draw air from the air stream. It would be very interesting to see this tested. I have seen this done with bottom breathers and they do not match the vararam's performance. Anyway that's my two cents.
Also I would like to tell you why I still post on CAI threads. I read these scientific explanations and I really do not want people who are looking for QTR mile ET improvements to be discouraged from purchasing a vararam based on these assumptions. The mathematics used probably is sound, I am sure you would not post
for the fun of it. But in practical application I know these arguments do not hold up to the actual results. No matter what anybody's stand point is, this setup does produce a significant performance gain over the stock OEM setup. But for what reasons I do not know with out further research. However I would surmise that it is not due to forcing more air into the engine. During a 1/4 mile run a Corvette is unlikley to be traveling quick enough to see this benefit. Therefore logic would dictate that the reason it produces more power than the stock setup would lie with the rest of the setup. The filter is of a freeflow nature, which means less restriction (combined with less efficent filtering, but it is impossible to have both), and the larger intake area. The stock setup is restrictive, but this is done to aide noise supression, fuel consumption and emissions. And the fact that it intakes abiant air thru the so called 'cold air ducts'. None of these factors are directly related to ramming more air into the engine, but they all can and do produce improvements in power output.
Remember competition race cars usually have to run an 'air restrictor' this in simple terms it a plate with a hole in it, this restricts the flow of air into the engine thus restricting the power that can be achieved. This is done to allow smaller engined cars such as Ferrari's compeat against the likes of the Corvette and Viper. Restriction or therefore the lack of restriction with aftermarket setups is usually the key to more power.
So providing the stock setup is causing a restriction ANY aftermarket free flowing setup will give more power. Whether the Vararam is better than the others? Well I don't know. It is certainly good, but the ultimate gains for road or even compition use will be limited, as getting the air into the engine is only part of the equation for big power. I would assume that many of the other systems if setup correctly would match the Vararam. And possibly even exceed it. Without further data it would be foolish to assume either way however.
There is plenty of research and background to swirl effect and venturi systems. I think as a whole the Vararam setup utilises many aspects. Mostly intential, but of course they may have just been lucky too.
However to actually have a direct comparison of the Vararam and the compition you would need to know the exact flow rates of each of the intake systems and filters and surface areas along with the intake temperatures on entering the air itake and then entering the intake manifold. Flow movement would be a lot harder to measure but not impossible. Without this data there is no way to know what is causing the increase/decrease in power.
By simply swapping the air filter in a Vararam setup for one of the same size but different material may have a dramatic affect on the setup. If power levels dropped then it would be logical to assume the filter is playing a large role in the gains, if the power increased then it would highlight the fact that the Vararam filter is still a restriction. If the the 2 filters have different flow abilities yet they both produced similar bhp gains then one could assume that the filter was only having a minimal affect on performance and that some other factor(s) where having a greater influence.
One thing that is a bonus with any external air intake setup is that from idle or stationary the air charge temperature should be that of or near ambiant, rather than being influenced by a heatsoaked engine bay, as the OEM stock setup will be. Once moving this advantage will either be lost or minimal.
You'll find a lot of the intaketechnolgy actually comes from the aviation industry. As it is here they have to deal with high intake speeds. And as performance and efficiency are paramount any benefits that can be ultilised usually are.
07-05-2005, 10:44 AM
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Originally Posted by shurite44
....
So tell me why do you think the vararam out performs other CAI's. I am convinced by personal experience and other members posts that it does. Do you think maybe people are just mistaken, (possibly placebo effect), or is there something besides just cold air and high flow filter going on with this device? You sound like you know something about this subject so I would be interested in your opinion.
.....
So tell me why do you think the vararam out performs other CAI's. I am convinced by personal experience and other members posts that it does. Do you think maybe people are just mistaken, (possibly placebo effect), or is there something besides just cold air and high flow filter going on with this device? You sound like you know something about this subject so I would be interested in your opinion.
.....
I will tell you from first hand experience that a Vararam will push your LTFTs postive (lean). I have more than a hundred hours of logs proving it. Air is hitting the MAF wire set in a way that it was not designed to. Along with the LTFTs the final WOT (PE) AFRs will read leaner also... Maybe this is where the power is coming from... OR a combination of cooler air and the leaner condition. I am assuming most owners just put the Vararam on and do not retune after the install, living with a lean (not too bad) state of tune and not knowing it... I did retune mine.
The Vararam will screw with your MAF calibration! I would like to try a BlackWing and see if I can hit the same rwhp and have a MAF calibration table that is closer to stock OR at least more predictable in a linear fashion when compared with the Vararam...
Last edited by SideStep; 07-05-2005 at 10:47 AM.
07-05-2005, 10:45 AM
#13
Originally Posted by BrightRed C5 SWFL
Thanks for the interesting writeup.
Only problem is that he didn't write it up.
http://www.snowgoercanada.com/tech_ram_air.shtml
Plagiarism is
Give credit where credit is due. Even if the article you cut and paste is bogus.
Addendum:
Still at it huh?
http://www.jagweb.com/aj6eng/v12_performance.html
"The Large Throttle kit will actually pass enough air to produce around 450 b.h.p. from a ....... but whilst cool air is certainly good for power, it is bad for cruise economy......
The rule about air temperature is simple, cool for power (maximum charge density), hot for economy (minimum charge density to reduce losses due to throttling). In this respect the standard arrangement is much better than many people think. Sure, the under-bonnet air temperature at idle can easily get up around 70 C but the faster the car goes the lower the air temperature falls - simply because the radiator is passing its heat to a much larger quantity of air per second - so at 80 m.p.h. the engine is breathing air at around 45 C......"
Last edited by '06 Quicksilver Z06; 07-05-2005 at 10:51 AM.
07-05-2005, 10:49 AM
#14
Melting Slicks
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Originally Posted by EB20003
Only problem is that he didn't write it up.
http://www.snowgoercanada.com/tech_ram_air.shtml
Plagiarism is
Give credit where credit is due. Even if the article you cut and paste is bogus.
http://www.snowgoercanada.com/tech_ram_air.shtml
Plagiarism is
Give credit where credit is due. Even if the article you cut and paste is bogus.
...good catch dude!!!
SOOO busted.... should have known it... 25 post and he gets on here and writes a small book....
Last edited by SideStep; 07-05-2005 at 10:53 AM.
07-05-2005, 10:55 AM
#15
Originally Posted by SideStep
...good catch dude!!!
SOOO busted....
Bottom line is you have a lot of people claiming to be able to somehow "debunk" the "ram air myth".
It may very well be a myth. I don't know or care. Only problem is that they offer up little if any alternate, feasable reason for why the Vararam works
07-05-2005, 10:57 AM
#16
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Originally Posted by EB20003
Only problem is that he didn't write it up.
Give credit where credit is due. Even if the article you cut and paste is bogus.
Give credit where credit is due. Even if the article you cut and paste is bogus.
Last edited by 300bhp/ton; 07-05-2005 at 11:13 AM.
07-05-2005, 10:58 AM
#17
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There is an old saying in drag racing. Cool the Fuel!
Cold fuel is dense and an engine produces more power.
Cool cans have been around for years.
Cold fuel is dense and an engine produces more power.
Cool cans have been around for years.
07-05-2005, 11:01 AM
#18
Le Mans Master
Originally Posted by EB20003
I recognized that article right away as I have read it on more than one occasion. I also recognized the second one he cut and pasted from.
Bottom line is you have a lot of people claiming to be able to somehow "debunk" the "ram air myth".
It may very well be a myth. I don't know or care. Only problem is that they offer up little if any alternate, feasable reason for why the Vararam works
Bottom line is you have a lot of people claiming to be able to somehow "debunk" the "ram air myth".
It may very well be a myth. I don't know or care. Only problem is that they offer up little if any alternate, feasable reason for why the Vararam works
Hey I saw in a high stall TC thread you are thinking about a C6. If you sell your vehicle late this year early next year give me a shout I am interested.
07-05-2005, 11:01 AM
#19
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Originally Posted by EB20003
I recognized that article right away as I have read it on more than one occasion. I also recognized the second one he cut and pasted from.
Bottom line is you have a lot of people claiming to be able to somehow "debunk" the "ram air myth".
It may very well be a myth. I don't know or care. Only problem is that they offer up little if any alternate, feasable reason for why the Vararam works
Bottom line is you have a lot of people claiming to be able to somehow "debunk" the "ram air myth".
It may very well be a myth. I don't know or care. Only problem is that they offer up little if any alternate, feasable reason for why the Vararam works
Last edited by SideStep; 07-05-2005 at 11:03 AM.
07-05-2005, 11:05 AM
#20
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Originally Posted by EB20003
It may very well be a myth. I don't know or care. Only problem is that they offer up little if any alternate, feasable reason for why the Vararam works
Originally Posted by 300bhp/ton
I
No matter what anybody's stand point is, this setup does produce a significant performance gain over the stock OEM setup. But for what reasons I do not know with out further research. However I would surmise that it is not due to forcing more air into the engine. During a 1/4 mile run a Corvette is unlikley to be traveling quick enough to see this benefit. Therefore logic would dictate that the reason it produces more power than the stock setup would lie with the rest of the setup. The filter is of a freeflow nature, which means less restriction (combined with less efficent filtering, but it is impossible to have both), and the larger intake area. The stock setup is restrictive, but this is done to aide noise supression, fuel consumption and emissions. And the fact that it intakes abiant air thru the so called 'cold air ducts'. None of these factors are directly related to ramming more air into the engine, but they all can and do produce improvements in power output.
No matter what anybody's stand point is, this setup does produce a significant performance gain over the stock OEM setup. But for what reasons I do not know with out further research. However I would surmise that it is not due to forcing more air into the engine. During a 1/4 mile run a Corvette is unlikley to be traveling quick enough to see this benefit. Therefore logic would dictate that the reason it produces more power than the stock setup would lie with the rest of the setup. The filter is of a freeflow nature, which means less restriction (combined with less efficent filtering, but it is impossible to have both), and the larger intake area. The stock setup is restrictive, but this is done to aide noise supression, fuel consumption and emissions. And the fact that it intakes abiant air thru the so called 'cold air ducts'. None of these factors are directly related to ramming more air into the engine, but they all can and do produce improvements in power output.