The Tiger is said to be lucky vivid, lively and engaging. Another attribute of the Tiger is his incredible bravery, evidenced in his willingness to engage in battle or his undying courage. Maybe he’s so brave because he is so lucky. But the Chinese say a Tiger having a Tiger in the house is the very best protection against the evils of fire, burglary.
Years of the Tiger
Tiger Years are third in the cycle and recur every twelfth year. The Chinese New Year does not fall on a specific date, so it is essential to check the calendar to find the exact date on which each Tiger year actually begins.
THE SIGN OF THE TIGER
Tigers do not find worth in power or money. They will be completely honest about how they feel and expect the same of you. On the other hand, they seek approval from peers and family. Generally, because of their charming personalities Tigers are well liked. Often, failing at a given task or being unproductive in his personal or professional life can cause a Tiger to experience a depression. Criticism from loved ones can also generate this type of Tiger reaction. Still, like all felines, Tigers always land on their feet, ready for their next act in life, pursuing it with unyielding energy and hunting it infallibly.
Tigers are also incorrigibly competitive - they simply cannot pass up a challenge, especially when honor is at stake, or they are protecting those they love. Tigers are unpredictable and it would be unwise to underestimate their reactions. They may appear cool, but they have the Big Cat's instincts to pounce at a moment's warning. Natural leaders, they have a strong sense of their own dignity, and if they find
themselves in the ranks, they can be stubborn and obstinate. In positions of power they can be difficult though stimulating bosses. Tigers are intelligent, alert, and farsighted. They have their fingers on the pulse. Good strategists and tacticians, they often have a hidden agenda. As long as they do not risk their luck too often, and keep their restless nature under control, their tactics usually pay off in life.
TIGER FACTS:
People born in the year of the Tiger share certain characteristics. The Tiger sign is an abbreviated way of characterizing that individual’s personality. Following are features associated with the sign of the Tiger.
Third in order, Chinese name - HU, sign of courage
Hour--am-4:59am Month--February
Western counterpart—Aquarius
CHARACTERISTICS
Courage, Vehemence, Self-Reliance, Friendliness, Hopefulness, Resilience, Vanity, Disregard
IN YOUR ELEMENT
The characteristics of the Tiger are tempered by one of the five Chinese elements of Metal, Water, Wood, Fire and Earth overlaying a 5-year cycle of characteristics on the original 12-year cycle.
THE METAL TIGER 195O AND 2010
The Metal element gives the Tiger its sharpness in action and speed of thought. Tigers born in the Metal year like to stand out in a crowd. With an inspiring assertiveness and competitive demeanor, they determine their goals and then do anything necessary to achieve them. This good-looking character sometimes suffers from mood swings and temper tantrums. The Tiger can be known to jump to conclusions or to act too quickly without weighing the options or understanding the consequences. This is a flaw Tigers must learn to curb.
THE WATER TIGER 1902 AND 1962
The Water element gives the Tiger a soothing characteristic making this breed a bit more tranquil. Their ability to consider feelings and ideas from other people makes them quite sensible and understanding. They are also born with a great intuitive power, which gives them accurate and excellent judgement. The Tiger is a bit indecisive, a habit of nature born of his routine of watching and waiting before leaping. Sometimes too, Tigers get caught sleeping or daydreaming, prohibiting them from going for the goals they initially set out to accomplish.
THE WOOD TIGER 1914 AND 1974
The Wood Tiger is more adaptable to working with others and therefore does not demonstrate the typical "take charge" attitude of other Tigers. The Wood element adds stability, giving him warmth of character that draws people in and makes the Tiger a popular person. They are not selfish creatures and will give their time, attention or possessions to anyone in need. These Tigers bring a solid practicality to any problem. They can control their urges to completely take over, letting others do the work. They must be aware of their slightly volatile tempers and short attention spans, and not let those characteristics get the best of them or cause them or their loved ones undue pain.
THE FIRE TIGER 1926 AND 1986
Eccentric and dramatic, Fire Tigers are aglow with passion and verve. They are outgoing, expressive and look on the bright side of things. They have the Tiger’s natural ability to lead others and are able to excite others simply with their own gift of enthusiasm. They can be funny and have great senses of humor. Tigers are powerful speakers and have the ability to command and persuade crowds through speech. Their own seemingly endless supply of energy can make them appear a bit dramatic, and it may make them more sensitive to cautious or down-to-earth approaches in others.
THE EARTH TIGER 1938 AND 1998
Earth Tigers are realists and tend not to get caught up by their own enthusiasm and excitement. They have a stout and sincere sense of responsibility that other Tigers haven’t quite cultivated and are not so easily distracted. These Tigers take life a little easier and have the ability to focus for longer periods of time, which in turn brings them success through continued effort. Earth Tigers must be careful not to take life too seriously and must remember not to lose their senses of humor or to ignore the needs and feelings of others.
HEALTH AND HOME
HEALTH
Tigers tackle everything in their lives in brief bursts of energy, collapsing afterwards in a heap of exhaustion. Normally they are soon back to full strength, but their approach can cause their long-term health to suffer. They should take it a little easier and learn to pace themselves to keep active longer and to prevent early burnout. They are blessed with flexibility and recover quickly from illness or pain. They owe it to themselves to relax a little. Along with the fitness of their long-term health, Tigers must be aware of how they react to and are affected by the consequences of their tempers. A Tiger’s meanest enemy is the damage he can inflict upon himself in the midst of a temper tantrum.
AT HOME WITH THE TIGER
Tigers take pride in being different than others and generally illustrate their originality best in their homes. Tigers can utilize their atmosphere with color and light. A Tiger’s home will be filled with exotic treasures from trips past and will include items such as Tibetan prayer mats or African carvings, confirming their desire to travel to distant places.
CAREER AND FINANCE
THE TIGER ON THE JOB
A quickness and an alert intelligence make Tigers fast learners. Tigers need a challenge. Add this to them being easily bored and it explains why Tigers tend to change careers more often than other Chinese Animals. Some Tigers don’t change their occupations frequently enough and thus tend to juggle jobs all at the same time. Most Tigers are natural born leaders who perform best knowing they are working towards positions of power and influence.
MONEY AND THE TIGER
Tigers depend on luck. They like to spend money, and also to share it. They can be quite impulsive spenders because they know they can always make more. Somehow, as luck would have it, they discover the end of the rainbow just before complete bankruptcy. They are willing to lose a fortune in their lifetime, if it means they will wind up with two.
TIGER CAREERS
Those born in the Year of the Tiger share the same kinds of goals and objectives in life. The occupations best suited for the Tiger are listed below:
TIGERS MAKE EXCELLENT:
Actors
Comedians
Chauffeurs
Musicians
Race Car Drivers
Pilots
Artists
Writers
Flight Attendants
Travel Agents
Advertising Agents
Office Managers
CONGENIAL BUSINESS PARTNERS
Whether Tigers are compatible with their business partners depends on whether their signs are harmonious or antagonistic to those of their business partners. Considering the congruity of their own characters and the characters of their business partners can also be very useful.
Tigers ruled by Benefit From Are Antagonistic to
Metal Earth Dogs Fire Oxen
Water Metal Pigs Earth Snakes
Wood Water Tigers Metal Roosters
Fire Wood Horses Water Rats
Earth Fire Dragons Wood Monkeys
Leisurely activities and pleasures
LIKES AND DISLIKES
Since Tigers are born under the same Animal Sign, they often share likes and dislikes. Following are similar likes and dislikes of the Tiger personality.
Tigers like:
Color Preference: Mid-green
Gems and Stones: Ruby, Diamond, Cat’s Eye
Suitable Gifts: Exotic cookbooks, travel guides, sports gear, mystery or crime novel, extreme sport lessons
Hobbies and Pastimes: Amateur theater, extreme sports, loud parties, intriguing vacations
Tigers Dislike: Not getting enough recognition for their efforts. Being inferior to others at work, impolite people
THE TIGER ON VACATION
Tigers like to live on the edge, to travel long distances conquering thrills and fears along the way. Never the homebody, Tigers prefer activity and excitement to relaxing days by the ocean reading a good book. They leave on a whim and return when they are ready to plan their next vacation. Action-filled getaways are sure to get a Tiger away for a long time!
FRIENDS AND ENEMIES
Tigers, born under the third Animal sign of the Chinese Zodiac, have the ability to lift the spirits of even the most depressed or lonesome individual they meet. Because of that attitude, Tigers have no problem making new friends. Actually, a Tiger person without a friend is quite miserable and sad. Like the Dragon, the Monkey, and the Rat, Tigers are most comfortable surrounded by friends and family.
As friends, Tigers are exceptionally warm and incredibly generous with their time, attention and money. Friends are always welcome in a Tiger’s home and will most often be greeted with a cup of coffee, an ear, a tissue, an open mind and an open wallet. Few friends could be as caring and affectionate, as quirky and surprising, or as genuinely interested as the Tiger.
Compatible Friends
Best Friends: Horses and Dogs
Mortal Enemy: Monkeys
TIGER PARENTS AND BABIES
Tiger parents are quite similar to the characters of their wildlife counterparts. They will walk through fire to protect their children or to defend them to others. As warm and affectionate as they are, they can become fierce and defensive when their kids are at stake. They lavish their offspring with treats and spoil them with generosity. Tiger parents can be fun as kittens, playing family games and getting great enjoyment from it. On the whole, they enjoy their children's company, having a good laugh and sharing a funny joke. Still, adult Tigers will become enraged if one of their children has gone too far, or is disrespectful. As open-minded and liberal as they are, they will not, under any circumstances, tolerate bad manners, or a lack of respect for other adults.
They take their role as parents very seriously, and they believe in the value of a good education. When their kids are small, Tigers like to tell them tales and read them stories. They like to talk about their childhood experiences, and use their stories to instill moral lessons or any ethical feelings. Tigers are decidedly convinced to make themselves the very best role models for their children that they can be.
TIGER INFANT AND CHILD
Tiger babies and children are cheerful children with a zest and passion for life that ignites their curious nature. Boys will and girls alike will enjoy the competitiveness and athleticism sports require. From an early age, Tiger children can’t pass on a dare or a challenge. Intelligent and friendly, Tiger children carry a curiosity about life and their environment. In class, they are apt to enjoy and do better at subjects that give them the ability and creative freedom to express themselves.
TIGER PARENT/CHILD KINSHIPS
Some parents immediately click with their children and others find they will never have a close relationship, no matter how hard they try to make it happen. Following are the compatibility ratings between Tiger parents and their children.
Tigers with Under the same roof Compatibility Rating
Rat put time into it for maximum effect **
Ox difficult *
Tiger look at life the same way ***
Rabbit smooth sailing ***
Dragon principled parenting ****
Snake going different directions *
Horse similar outlook ****
Sheep loving relationship **
Monkey pretty divided *
Rooster separate ideas *
Dog strong bonds and deep friendship ****
Pig to get the good you’ll survive the bad ***
*uphill struggle **some complications ***easy bonding ****on the same wavelength
LOVERS AND SPOUSES
THE TIGER LOVER
Tigers are incredibly sexy people, beautiful to most people and sensually romantic. They are spontaneous lovers who never lose their creative spark or flare for an evening of passion. They offer their partner a hint of danger and exhibit a curiosity for the unknown.
MARRIAGE
Once a Tiger has committed himself to you, he can tend to want to dominate or lead you. This is a natural nurturing mechanism and must be kept under close watch to avoid complete control. For the negative effects a Tiger can have on
his partner, there are a zillion positive things he will bring to the relationship. Trust, passion, politeness and spontaneity are only a few characteristics of the Tiger mate.
THE TIGER LOVE PARTNER
Tigers love excitement and need someone who can keep up with all they want to do and see. His partner must also be able to stand the mood swings, the ups and downs, the good with the bad. Chinese horoscopes are very specific about which partnerships have the potential to be successful in love and in business. Yet, though destiny can point us ion the right direction, we must still make all efforts to maintain loving relationships. Following is a brief description of how a Tiger will affect a relationship with other Animal signs.
PARTNERS IN LOVE
Tiger*Rat
Lots of friendship, but many temper tantrums will blur the good times.
Tiger*Ox
This is one of the worst possible pairings…that’s probably why you are so drawn to each other.
Tiger*Tiger
You are both so dominant and creative you are bound to ignite each other’s curiosity.
Tiger*Rabbit
This is another good match.
Tiger*Dragon
A brave combination plenty of fire to keep you interested.
Tiger*Snake
You are on completely different paths that aren’t worth crossing.
Tiger*Horse
You are destined for an exciting life together.
Tiger*Sheep
Not enough openness to try to keep it together.
Tiger*Monkey
You’ll aggravate each other to death!
Tiger*Rooster
Little communication causes big issues.
Tiger*Dog
You are a winning combination…admiration and respect fuel this partnership.
Tiger*Pig
Humor and friendship make this partnership a success!
Love Partners at a Glance
Tigers with Tips on Togetherness Compatibility
Rat value each other’s opinions **
Ox striking tantrums *
Tiger to much mind changing **
Rabbit differences are similar ***
Dragon a great partnership ***
Snake don’t go for it *
Horse good match ****
Sheep marriage won’t work **
Monkey pretty frustrating *
Rooster make a decision or leave **
Dog stable and affectionate ****
Pig humor keeps you together ****
COMPATIBILITY RATINGS:
*dispute **keep working at it ***intense sexual attraction ****angelic
EAST MEETS WEST
ARIES TIGER
Volatile and active, these people are whirlwinds who must enjoy open spaces and a lot of activity. Feeling pinned down to one decision or one destination is an Aries Tiger’s worst nightmare. These people are generous and brave as well as deeply passionate people.
LIBRAN TIGER
These Tigers play fair and value justice in their everyday lives. They are known to flail in their own personal decision-making efforts.
TAUREAN TIGER
More down-to-earth than other Tigers, these people are practical and will finish tasks they start. They work well under pressure and can maintain their workloads through amazing efforts. They are passionate in their partnerships and provide stability to their loved ones.
SCORPIO TIGER
This is the most intense Tiger of them all. Scorpio Tigers are deeply emotional and sensitive people, extremely focused on the task at hand. They are strong-willed and motivated and don’t like contradiction.
GEMINI TIGER
These people like to move about freely. They yearn to see new places and to meet new people in their travels. They are quirky, funny, intelligent and lively and are more comfortable being the life of the party than being a guest there.
SAGITTARIAN TIGER
These Tigers have a great appetite for life and thrust themselves into everyday of their lives. They are mostly extroverts who enjoy being out and about in strange places. They also like to be spontaneous and often jump to conclusions before weighing the consequences.
CANCERIAN TIGER
The Cancerian Tiger is a romantic individual who is sensitive and tenderhearted. This character needs a loving, honest relationship to thrive.
CAPRICORN TIGER
These people work long, hard hours to achieve the level of success they believe they are destined for. Their career will always be the most important thing in their lives, with love and relationships following a close second and third.
LEONINE TIGER
This Tiger expects the respect he believes he deserves. He works hard for his status and position and commands a certain presence when he enters a room.
AQUARIAN TIGER
These Tigers ignore the rules and regulations of society and choose instead to focus on matters of the heart. They tend to forget about the emotions involved in these matters, which causes them to seem harder and less sensitive.
VIRGO TIGER
These Tigers can be pretty picky when it comes to choosing a partner. They have an eye for detail that can cause them to be a little neurotic at times.
PISCEAN TIGER
Quite sensitive and kind, these Tigers are a bit more reserved than most. They are patient and loving and often supress the fiery passions that can accompany the Tiger personality. Once they decide they want a partner, they will stop at nothing to get him or her.
Monday, November 30, 2009
Monday, November 16, 2009
Overview: Supercharger vs. Turbocharger
By Brian Ferrari
Jul 19, 2004, 17:00
The intention with this article is to shed some light on the theories behind turbocharging the modern engine, and the wonderful advantages it gives us in both speed and basic engine design issues. This post is also to try and give people a better understanding of supercharger systems and how they work to make such a simple thing as an engine even simpler (speaking in terms of tuning). I personally am tired of seeing people bicker over the differences between the two basic designs, and would like everyone to note the vast similarities among them instead. So without further delay... I will start with this simple statement:
"It makes no sense to build a naturally aspirated engine if what you are looking for is good power output."
To understand why this is so obviously true, we need to break the concept of an engine down into its simplest parts. There are 4 main parts to an engine that concern airflow:
-the induction system
-the cylinder head(s)
-the exhaust system
-the camshaft(s)
Now if you think of the engine in terms of airflow and forget about fuel for a minute, it becomes a very simple matter really. What we want to do is best flow air through the cylinder head, from the induction system to the exhaust system and then out into the world again. This is best & most naturally accomplished by pressure variation, because as almost anyone with a high school education knows, air naturally flows from areas of higher concentration (pressure) to lower concentration (pressure). Now let's assume for a minute that we are talking about an engine at or near sea level, well we can just forgo the exact physics of things and say that at both the induction system's inlet & the exhaust's outlet we have equal pressure (just under 15psi absolute pressure). So in order to flow air into this system we must always be working a balancing act between the three fundamental sections of the engine, which are exposed to each other only through the camshaft's orchestration of the valves. So forget everything else you know about engines and start thinking of what's under your hood in this way for the rest of this post :).
NA ENGINES (naturally aspirated)
These must work within a maximum pressure variation of 0psi (which is really hard to create without massive pumping losses) and 14.7psi (maximum atmospheric pressure @ sea level). To add to the basic problem of how to flow air into and out-of this system, both ends of the system start out at the same pressure, meaning air doesn't naturally want to go IN or OUT. This can be accurately termed as a “pain in the ass”. Now engineers and enthusiasts alike have long been fascinated with how to make power from this setup, but I am talking specifically about supercharged engines here, and as I already stated "It makes no sense to build a naturally aspirated engine if what you are looking for is good power output." So forget about how you can best accomplish this through piston movement and it's effects on cylinder pressures, and understand that it's just a whole lot easier to get an engine to work if it's supercharged.
FI ENGINES (forced induction)
From a pure engine design standpoint, it makes MUCH more sense to pressurize the intake system than to run NA. When only the intake system is running under pressure well above atmospheric, it becomes perfectly obvious that air is going to want to flow through the engine exactly the way we want it to, and both cam timing & exhaust sizing becomes much less important to getting the system to work right (as it was before in NA setup). The air will naturally want to flow into the cylinder head, and then after the very strong power stroke (thanks to all that air) it will naturally want to flow out into the lower pressure exhaust system afterwards. Everything in the engine will be working at pressure above atmospheric and the pressure differences will be greatest in the induction system, so all air will want to exit out the tail pipe quickly and efficiently. One other thing should be said here: turbos technically ARE superchargers. A supercharger is ANY device that pressurizes the intake to above atmospheric pressure, and turbos do this exactly like superchargers do. The only difference is in how a turbo gets the energy necessary to perform it's job, and also that the turbo contributes to supercharging the exhaust system (or more accurately a portion of it, the exhaust manifold).
THE CASE FOR SUPERCHARGING
Since a crank driven s/c (s/c = supercharger) is what people are normally talking about when they use the term supercharger, I will no longer say "crank driven" to make the distinction between it and a turbo. Now using a supercharger makes a ton of sense simply because it only has a direct effect in pressurizing the engine on the side we want it to, the induction side. Since pressures will always be higher here than in any other part of the system (except of course during the engine's power stroke, but that's always sealed off from the rest of the system so we can forget about that complexity), it's very easy to make this combination a powerful one. NA engines often use large amounts of valve overlap to get the whole system to work properly at higher RPM, which has obvious drawbacks in that it's possible for the intake system and exhaust systems to interact in a negative way (since they operate at similar pressures). It's sometimes just as easy to get air flowing backwards through the system as it is to go forwards in an NA setup, which is one reason camshaft choice is so important to where in the RPM band best power will be produced. And here is where the beauty of supercharging is; neither valve overlap amounts nor perfect exhaust system designs are completely essential to keep everything flowing in the right direction. No matter how long the exhaust is exposed to the intake system through valve overlap, air should NEVER pass backwards through the system unless the supercharger stops working.
THE EVIL OF SUPERCHARGING
The evil of supercharging is that some of the power we finally get from combusting the air/fuel mixture must go back into powering the supercharger. So here we have designed this whole system that works so well, yet we have to power it with some of our hard earned torque. This is not a good thing, but then again nothing so simple is ever going to come for free. Do superchargers work? Of course they do, which is why many racing engine uses the technology unless the rules prohibit it. The net result is more total power from the system, but a portion of this power must be sapped from our output to make it all work.
THE CASE FOR TURBOCHARGING
This section is easy to write, because it's exactly the same thing as the supercharger portion. We have all of the same advantages, except for one major benefit. That benefit is that turbocharging runs off what is largely wasted energy, so that damn drawback of needing to power the system with some of our hard earned torque is removed. In this way, a turbocharger addresses the one main drawback to using a supercharger, but as you will see in a second the supercharger addresses the one main drawback of turbocharging.
THE EVIL OF TURBOCHARGING
Hopefully you now understand why it makes so much sense to forgo designing engines for NA use and just supercharge the sucker instead, at least when we are talking about how to best make power. And if you have been following what I have said, you will also understand the bad effect turbos have on our little perfect world of pressure variation.
A turbo is an ingenious little design that harnesses the wasted kinetic energy we dump out through the exhaust system to actually force more air into the engine. This is good for the same reasons that supercharging is good, but it has one major drawback: it of course increases the pressure within a portion of the exhaust system. While turbocharging a motor increases the amount of air that can be flowed into it, it has a negative effect on how easily we can flow it back out again. This weakens our positive pressure difference between these two fundamental sides of the engine, and causes both cam timing & exhaust system design to again become extremely important to making good power. This is most certainly not a good thing, but can a turbo overcome this drawback with the other inherent good it possesses? It certainly seems so, because in most current forms of racing where the rules don’t probihit the use of tubos or slap restrictions on their use, the turbo reigns supreme in terms of engine power output.
Now I didn't post this to make a statement about which system will work better for your intended use, because the answer is (as usual) "it depends". Sorry, but if there was such a clear cut answer do you really think people would still be debating this topic? A long time ago someone would have proven everyone else wrong, and either turbos or superchargers would no longer exist. Remember, these systems were designed and in use on production vehicles long before most of us were born, so it's not like this is a new debate. The purpose here is to educate people on exactly why we would want to supercharge or turbocharge an engine in the first place. Also I wanted people to see, from a basic and theoretical perspective, how each system is different in its function and it's relative pros & cons. Hopefully this discussion of basic theory helped some of you come to a better understanding of FI engines, and that my leaving out any real world examples actually made it easier to understand. I have written an article concerning the technical differences of the common systems, giving examples of different supercharger designs and their advantages/disadvantages. You can read it HERE. And please, any questions or comments, post ‘em here.
By Brian Ferrari
Jul 19, 2004, 17:00
The intention with this article is to shed some light on the theories behind turbocharging the modern engine, and the wonderful advantages it gives us in both speed and basic engine design issues. This post is also to try and give people a better understanding of supercharger systems and how they work to make such a simple thing as an engine even simpler (speaking in terms of tuning). I personally am tired of seeing people bicker over the differences between the two basic designs, and would like everyone to note the vast similarities among them instead. So without further delay... I will start with this simple statement:
"It makes no sense to build a naturally aspirated engine if what you are looking for is good power output."
To understand why this is so obviously true, we need to break the concept of an engine down into its simplest parts. There are 4 main parts to an engine that concern airflow:
-the induction system
-the cylinder head(s)
-the exhaust system
-the camshaft(s)
Now if you think of the engine in terms of airflow and forget about fuel for a minute, it becomes a very simple matter really. What we want to do is best flow air through the cylinder head, from the induction system to the exhaust system and then out into the world again. This is best & most naturally accomplished by pressure variation, because as almost anyone with a high school education knows, air naturally flows from areas of higher concentration (pressure) to lower concentration (pressure). Now let's assume for a minute that we are talking about an engine at or near sea level, well we can just forgo the exact physics of things and say that at both the induction system's inlet & the exhaust's outlet we have equal pressure (just under 15psi absolute pressure). So in order to flow air into this system we must always be working a balancing act between the three fundamental sections of the engine, which are exposed to each other only through the camshaft's orchestration of the valves. So forget everything else you know about engines and start thinking of what's under your hood in this way for the rest of this post :).
NA ENGINES (naturally aspirated)
These must work within a maximum pressure variation of 0psi (which is really hard to create without massive pumping losses) and 14.7psi (maximum atmospheric pressure @ sea level). To add to the basic problem of how to flow air into and out-of this system, both ends of the system start out at the same pressure, meaning air doesn't naturally want to go IN or OUT. This can be accurately termed as a “pain in the ass”. Now engineers and enthusiasts alike have long been fascinated with how to make power from this setup, but I am talking specifically about supercharged engines here, and as I already stated "It makes no sense to build a naturally aspirated engine if what you are looking for is good power output." So forget about how you can best accomplish this through piston movement and it's effects on cylinder pressures, and understand that it's just a whole lot easier to get an engine to work if it's supercharged.
FI ENGINES (forced induction)
From a pure engine design standpoint, it makes MUCH more sense to pressurize the intake system than to run NA. When only the intake system is running under pressure well above atmospheric, it becomes perfectly obvious that air is going to want to flow through the engine exactly the way we want it to, and both cam timing & exhaust sizing becomes much less important to getting the system to work right (as it was before in NA setup). The air will naturally want to flow into the cylinder head, and then after the very strong power stroke (thanks to all that air) it will naturally want to flow out into the lower pressure exhaust system afterwards. Everything in the engine will be working at pressure above atmospheric and the pressure differences will be greatest in the induction system, so all air will want to exit out the tail pipe quickly and efficiently. One other thing should be said here: turbos technically ARE superchargers. A supercharger is ANY device that pressurizes the intake to above atmospheric pressure, and turbos do this exactly like superchargers do. The only difference is in how a turbo gets the energy necessary to perform it's job, and also that the turbo contributes to supercharging the exhaust system (or more accurately a portion of it, the exhaust manifold).
THE CASE FOR SUPERCHARGING
Since a crank driven s/c (s/c = supercharger) is what people are normally talking about when they use the term supercharger, I will no longer say "crank driven" to make the distinction between it and a turbo. Now using a supercharger makes a ton of sense simply because it only has a direct effect in pressurizing the engine on the side we want it to, the induction side. Since pressures will always be higher here than in any other part of the system (except of course during the engine's power stroke, but that's always sealed off from the rest of the system so we can forget about that complexity), it's very easy to make this combination a powerful one. NA engines often use large amounts of valve overlap to get the whole system to work properly at higher RPM, which has obvious drawbacks in that it's possible for the intake system and exhaust systems to interact in a negative way (since they operate at similar pressures). It's sometimes just as easy to get air flowing backwards through the system as it is to go forwards in an NA setup, which is one reason camshaft choice is so important to where in the RPM band best power will be produced. And here is where the beauty of supercharging is; neither valve overlap amounts nor perfect exhaust system designs are completely essential to keep everything flowing in the right direction. No matter how long the exhaust is exposed to the intake system through valve overlap, air should NEVER pass backwards through the system unless the supercharger stops working.
THE EVIL OF SUPERCHARGING
The evil of supercharging is that some of the power we finally get from combusting the air/fuel mixture must go back into powering the supercharger. So here we have designed this whole system that works so well, yet we have to power it with some of our hard earned torque. This is not a good thing, but then again nothing so simple is ever going to come for free. Do superchargers work? Of course they do, which is why many racing engine uses the technology unless the rules prohibit it. The net result is more total power from the system, but a portion of this power must be sapped from our output to make it all work.
THE CASE FOR TURBOCHARGING
This section is easy to write, because it's exactly the same thing as the supercharger portion. We have all of the same advantages, except for one major benefit. That benefit is that turbocharging runs off what is largely wasted energy, so that damn drawback of needing to power the system with some of our hard earned torque is removed. In this way, a turbocharger addresses the one main drawback to using a supercharger, but as you will see in a second the supercharger addresses the one main drawback of turbocharging.
THE EVIL OF TURBOCHARGING
Hopefully you now understand why it makes so much sense to forgo designing engines for NA use and just supercharge the sucker instead, at least when we are talking about how to best make power. And if you have been following what I have said, you will also understand the bad effect turbos have on our little perfect world of pressure variation.
A turbo is an ingenious little design that harnesses the wasted kinetic energy we dump out through the exhaust system to actually force more air into the engine. This is good for the same reasons that supercharging is good, but it has one major drawback: it of course increases the pressure within a portion of the exhaust system. While turbocharging a motor increases the amount of air that can be flowed into it, it has a negative effect on how easily we can flow it back out again. This weakens our positive pressure difference between these two fundamental sides of the engine, and causes both cam timing & exhaust system design to again become extremely important to making good power. This is most certainly not a good thing, but can a turbo overcome this drawback with the other inherent good it possesses? It certainly seems so, because in most current forms of racing where the rules don’t probihit the use of tubos or slap restrictions on their use, the turbo reigns supreme in terms of engine power output.
Now I didn't post this to make a statement about which system will work better for your intended use, because the answer is (as usual) "it depends". Sorry, but if there was such a clear cut answer do you really think people would still be debating this topic? A long time ago someone would have proven everyone else wrong, and either turbos or superchargers would no longer exist. Remember, these systems were designed and in use on production vehicles long before most of us were born, so it's not like this is a new debate. The purpose here is to educate people on exactly why we would want to supercharge or turbocharge an engine in the first place. Also I wanted people to see, from a basic and theoretical perspective, how each system is different in its function and it's relative pros & cons. Hopefully this discussion of basic theory helped some of you come to a better understanding of FI engines, and that my leaving out any real world examples actually made it easier to understand. I have written an article concerning the technical differences of the common systems, giving examples of different supercharger designs and their advantages/disadvantages. You can read it HERE. And please, any questions or comments, post ‘em here.
Subscribe to:
Posts (Atom)