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Turbo 101

 

Old 01-07-2006, 11:42 AM
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Disclaimer: As with any type of Automotive Upgrade, Forced Induction is full of Grey, it's never as easy as a Black and White answer. There is always an exception to any example. The information presented in this thread is just that, basic information. It is possible to go into much further detail on the subject, which is up to you in the future. When types and styles of forced induction systems are compared it is under the condition that they are all of similar capability. It is always possible to make statements false by taking them out of context or changing the basic parameters of the discussion. When I started to boost cars I would have loved to have had a baseline of information before starting my research. That is why this is here, for you.


-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-



No Insult to anyones Knowledge Base, This is More of an introduction to Turbos and Superchargers for thoes who simply do not know. Please feel free to add or correct faults to this thread. It is not perfect nor do I think I am..



Everyone, I mean everyone from a 4 Year old kid to my 80 Year old
Gramma knows that the word "Turbo" has something to do with making
more power. It's a refined system that simply put is a force multiplier.

First, you must understand how an engine makes power before we talk
about "Nitrous" and "Forced Induction" IE. Super Chargers and Turbo Chargers.


This Animation is of a Two Stroke System, Here is a link forthe 4 Stroke..

http://auto.howstuffworks.com/engine4.htm

Many of us have seen the T.V. Commercials for Oil where a cut away or
even an animation shows us what can never be seen, the events in the
combustion chamber. Others more qualified on N/A will be able to give a more detailed cycle
including timing of ignition and cams; this is the simple version of all 4
stroke gasoline motors. This is also found in the Mazda Protégé engine.

Suck – The Pistons starting at the top of the cylinder drop creating a
vacuum in the chamber, the intake valves open at the beginning of this
cycle and air and fuel are pulled into the chamber from the intake manifold.

Squeeze – All valves are closed and the piston rises, compressing this
mixture, just past the pistons highest point, (Top Dead Center) or TDC,
the spark is released and the entire mixture goes…

Bang – The explosion or combustion of the air and fuel force down on the
piston, through the rod to the crank, creating rotation that is sent through
the “transmission” (Transmission of Power to the Drive wheels).

Blow – When the combustion is complete and the piston is at its lowest
point, the exhaust valves open and the piston travels up again, this time
forcing the exhaust out of the chamber into the exhaust manifold and out the pipe.

(See Suck for the next step) :

This is the basic 4 Cycles that "OTTO" engine goes through. Each
piston fires in sequence every half revolution to make an even spacing of
firing and thus a well balanced power output.

The engine in its Normally Aspirated state (N/A) as quickly explained
above sucks the air into the chamber. Any restriction in this system will
result in less volume of air being able to make it into the chamber and
thus less fuel being able to combust. Less power. Because more is better,
many of us try to reduce the amount of effort the engine will have to work
to allow for the most air to be delivered and the most exhaust being
removed from the engine. Having said that, Cold air systems and
free flowing exhaust systems do wonders to free up HP. Timing and other
tricks such as porting and polishing the intake and exhaust system allow
for less drag in the system. Eventually you end up at a point where the
engine has reached its limit, simply adding more fuel will not make
more power because there isn’t enough air to complete the explosion
and it goes out. This situation is called “Rich” you will actually loose
power to this. The opposite to this condition is called “Lean” we are
going to talk about this in the next section as it’s the major problem
when dealing with “Forced Induction”.

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Old 01-07-2006, 11:42 AM
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The simplest explanation of how forced induction works is…

“Forcing more air and fuel into the engine”

Turbo Will Be discussed First. The Supercharger is in the next section.

It makes sense, it’s rather easy to see after knowing how an engine makes power that if you add more air and fuel to the same cylinder, you are able to burn the extra fuel completely and this will result in a larger explosion in the chamber…more force on the piston, more power at the wheels. First I’ll explain how the turbine is built and works. Then I’ll get into how it works for the engine.





Top is a picture of a Garrett T04Z. The Darker side (Iron or Hot Side) is where the exhaust is forced into the “Exhaust Inlet”.
(Square Flange)

After being forced through the "Hot Wheel" or "Turbine Rotor", it leaves out the round hole on the left of the second picture called the exhaust outlet.

This "Hot Wheel" is connected to a second turbine by a shaft supported by the center section of the turbo called the bearing housing.

This second turbine is housed in the lighter colour side (Aluminium or Cold Side)
It is where the air is taken and pumped at very high speed by the compressor wheel out the compressor outlet.

The turbine is required to spin very fast to pump, in the range of 50,000 RPM to 125,000 RPM.
(125,000 should be considered the point of failure or breakdown)

This shaft must be fed by oil from the engine at all time from a dedicated line from the lubrication system. Filtered oil is sent through the bearing housing and passes around and on the journal or ball bearing. This oil is subjected to massive heat and pressure resulting it the oil being transformed into a milky puss, the better the oil, the better it will stand up to this before breaking down. The oil returns to the lubrication system where it is filtered and pumped again. Most modern bearing housing are also liquid cooled to reduce the heat of the entire area prolonging oil and bearing life.

The Picture of the Bearing Cross section is the Attachment...



The Turbo is like a human heart. All the ports in it have to be hooked up for it to work. This is why it takes alot of time to build a kit from scratch or even bolt up a kit. You can't just install the manifold and wait till next weekend to do the rest.

The fact that a turbo is driven by exhaust gasses and not tied to the motor is it’s biggest plus. If designed well, a turbo will spool low on the power band and hold max boost all the way through the rev range. A short shift and a well set Blow-off valve will have you back at max boost as soon as you are in the next gear. The result is the engine is receiving full boost for the entire sweep unlike the supercharger that makes peak boost only just shy of redline. If Boost = HP gains, you quickly see how desirable this is. The second Pro for a turbo is that the energy used to turn it is simply a waste product from the internal combustion of the engine. If the turbo adds 100 HP to the engine, on paper you are getting 99 HP at the wheels. The loss is due to the backpressure that is imposed on the engine which can be a factor if the turbo is too small. The process of internal combustion is not perfectly efficient. If it were, all the energy released by the fuel would go directly to turning the crank, but there is heat and frictional loss. There is a lot of loss due to heat, some ends up in the block and is taken away by the coolant. The rest travels out the exhaust valves and expands into the exhaust manifold. This expanding gas spools the turbo as it leaves the car. A turbo reclaims some of that wasted energy to make the car more powerful. It is a real slick refined system.
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Old 01-07-2006, 11:43 AM
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Here is a Supercharger on a Mazda Miata. What a Supercharger does is
very similar to a Turbo, however, how that air is forced is very diferent.

Each has it drawbacks and advantages.









The supercharger is often much easier to install, there are fewer problems because the system has nothing to do with the exhaust, there is no problem with boost control because it’s as simple as changing to a larger or smaller drive pulley. However, a supercharger is driven by the belts and for it to function; it robs the engine of power just like power steering or an alternator. Luckily the Supercharger usually makes a lot more power than what is required to drive it. If the engine makes 100 more Hp and it only takes 30 Hp to drive the supercharger, the engine is 70 Hp Stronger. This is why many chose turbo over Supercharger and is it's only real negative.

You still have to build the engine to handle the total boost but get a bit less HP than the turbo running at the same boost due to the driveline loss.

The supercharger comes in several forms and sizes just like a turbo.

Some setups look like a turbo and even allow the use of an Intercooler to increase performance and reliability.

Most are bolted directly to the intake manifold or even replace the entire intake manifold.

The Supercharger is instant power and is creating boost all the time. However because it's linked directly to the RPM of the engine by a belt, the amount of boost it adds is directly related to the speed of the engine. So at 3000 RPM you would get 5 PSI of boost, At 6000 RPM you would get 10 Psi.

Superchargers are much more popular with Mustangs, American Muscle Cars and other large displacement cars.
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Old 01-07-2006, 11:43 AM
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The Turbo has a problem known as "TURBO LAG", Lag is the time it takes from when you try to accelerate to when the turbo has spooled up to create the pressure required by the engine. On a car with a very large turbo for the size of engine, this lag can be a very big negative in the cars performance. The Turbo will only be able to make boost at the upper range of the power band because of the amount of exaust gas required to spool it. A Turbo that is smaller will spool much faster and much lower on the power band, but it will have to spin much faster to make the same boost as the larger turbo. So there must be a balance between Lag and Boost. The requirements of the engine must be taken into account when selecting the Turbo for the application. Most turbo kits are very well thought out and are complete; however, if the kit is only designed to run at 6 Psi, the entire kit may be completely inadequate for 10 Psi. Choose the turbo wisely; it is one of the most important design choices that will change how your car performs.
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Old 01-07-2006, 11:44 AM
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Old 01-07-2006, 11:44 AM
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^^^Great Read.

"Nitrous Oxide"



:gay:



So Nitrous is not Forced Induction, but I feel it should be mentioned.

Ok, Now that we have a very good understanding of the OTTO Cycle engine; "Suck Squeeze, Bang, Blow", we can talk about the last big power adder.

Forced Induction (Either Turbo or Supercharger) build pressure to increase the number of atoms of Oxygen in the cylinder. This increase allows more fuel to be burned. Nitrous Oxide achieves the same goal in a very different way.

Air is made up of Nitrogen 78% and Oxygen 21% (Other Trace Gasses)

Nitrous is made up of Nitrogen 66% and Oxygen 33%

So you see by simply dumping Nitrous in the intake, it will displace some of the air and the engine will get more molecules of Oxygen for the same pressure. The end result is the same as a Forced induction, there is more Oxygen in the mixture.

"Why not use Pure Oxygen if your goal is simply to add Oxygen"

Many of us remember what happened in Chemistry class when a burning splint was blown out and placed in Oxygen. It lit again; this environment makes for a normal fire to turn almost explosive. Same reason why even in the 50's and 60's, you could not smoke near an Oxygen tent in a hospital. Any source of ignition would become dangerous in the environment. So Here it is, an engine creates heat, a hot engine is efficient but there is a he point where the components of the engine start to melt. Cooling systems remove and steady the heat in an engine to an operating temperature but are unable to deal with the spike in heat that oxygen would introduce. Oxygen also wears away at metal, basically Rusting and reducing its integrity. Oxygen, directly in an intake would turn a controlled explosion in a normal engine, into a much faster and destructive explosion. The tensile loading on the engine would increase exponentially just as in detonation plus the amount of heat that would be created would cook all the components inside near instantly. One of the reasons that Nitrous is used is that as the Nitrogen is stripped from the Oxygen, it absorbs heat from the immediate area. Just like a CO2 Canister gets cold on a paintball gun, Nitrous gets cold in the cylinder. You get the power and the heat remains almost unchanged. Expanding gas absorbs heat energy. The same principle in A/C and refrigeration systems.


Nitrous Oxide adds more molecules of Oxygen that will allow for more fuel to be burnt in the same cylinder. = More Power.

Oxygen is too volitile and will heat too much and destroy components. = Boom.

Here is a great read on N2O...

http://www.chm.bris.ac.uk/motm/n2o/erratum.htm

Beacuse the Gas is in a Bottle in your car, It will eventually run out. Nitrous is not used for any type of endurance race. Turbos and Superchargers are normally used because they simply use the fule in the tank for the HP.

Quote Web Link.. Marshall Hiepler
"Although it does provide impressive power gains for naturally aspirated engines, the rate of depletion of a 10 - 20 lb bottle of nitrous oxide is rapid. Depending on the displacement of the engine, only 2 - 5 minutes of boost could be realized. It is for this reason, that the use of nitrous oxide is primarily confined to drag racing, street racing, and other short duration racing applications. Maximum acceleration is the primary objective for these sports, while endurance is not. These engines are designed with large intake and exhaust valves, and gas flow passages for maximum rpm - which is where the power plant will spend the majority of its time; however briefly. The Nitrous bottle is plumbed to an electric solenoid valve which permits nitrous oxide to flow in a liquid state into the engine's air intake manifold via precise orifices to control flow. These orifices are engineered to deliver a measured supply of the liquid nitrous oxide, which has been calculated to be appropriate for wide open throttle only. The nitrous oxide changes state immediately upon injection into the intake manifold, thus affording the advantages of its latent heat factor, as you described. These advantages are numerous, as you also mentioned, the most notable being the change in charge density. The overall density of the fuel/air mixture being drawn into the combustion chamber increases sharply as the nitrous oxide changes from liquid to a gas within the intake passage. Most engine builders will incorporate an additional means of simultaneously enrichening the fuel to air ratio, so as to take full advantage of the extra oxygen that is released by the nitrous oxide during combustion. Furthermore, the reduced temperature of the intake charge allows for an increased compression ratio that would otherwise not be possible, due to the pre-detonation of the charge during the compression stroke. Pre-detonation must be avoided at all cost, as it is extremely damaging to most race engines. In addition to the advantages gained with the use of higher compression ratios, an effective alternative is to pressurize the intake charge. This is often done with a turbo-charger which takes advantage of the expansion of the exhaust gases as they exit the combustion chamber. Although heating of the intake charge is a negative drawback commonly associated with the turbo-charging of engines, this factor is effectively negated when used in conjunction with nitrous oxide injection."

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Old 01-07-2006, 11:44 AM
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By Definition a Turbo is a Supercharger yes, but it isn't because of the way it operates. So it's just simply known as a Turbocharger because it is a pair of turbines connected by a shaft.

The noun supercharger has one meaning:
Meaning #1: compressor that forces increased oxygen into the cylinders of an internal-combustion engine

"Superchargers"

A Centerfugal Supercharger combines the negaitve qualities of both a Turbo and a Supercharger. They are the least capable at making good boost pressure but are effecient at low pressure applications. They make heat like a turbo but Rob Horsepower like a supercharger. So that makes them...Moderately desireable for big horsepower. More for minor power adding.


------------------------------------------------------------------------------

From.. http://en.wikipedia.org/wiki/Centrifugal_supercharger

The centrifugal type supercharger is practically identical in operation to a turbocharger, with the exception that instead of exhaust gases driving an impeller, there is only a compressor housing, and that is driven from the crankshaft via a drive belt. As such the centrifugal exhibits the same benefits and down-sides. Boost increases with the square of RPM (unlike the linear nature of the positive displacement devices), however low-rpm boost suffers due to the fact that air can pass back through the supercharger with little restriction until RPMs rise sufficiently to counteract the effect. Of all the belt-driven supercharger types this type exhibits the highest efficiency, and due to its design and lack of low-down boost is often employed on near standard compression engines. The Roots type supercharger and the twin-screw type supercharger, however, produce low-rpm boost and as such feel far more reactive on the road.




That's alot of air..

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Old 01-07-2006, 11:45 AM
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"Roots Supercharger"

Known more commonly as a Blower, Should be considered "Old Tech".

Used in Two Stroke Deisel Engines and many classic Hot rods that are true to their roots.

A large and relitively ineffecient type of supercharger (By Todays Technology). Normally a pair of "Gears" mesh at moderate speed to create positive pressure on the outlet side of the charger. This "Blower" is normalkly bolted directly to the intake manifold, makes very litttle heat in the process of creating boost and has no requirement for an intercooler.



------------------------------------------------------------------------------
From: http://en.wikipedia.org/wiki/Roots_type_supercharger

The Roots type supercharger or Roots blower is a positive displacement type device that operates by pulling air through a pair of meshing lobes not dissimilar to a set of stretched gears. Air is trapped in pockets between the lobes and carried between the intake side to the exhaust. The supercharger is typically driven directly from the engine's crankshaft via a belt. In order for most typical Roots superchargers to deliver air at greater pressure than atmospheric, they should be geared so that they turns faster than the engine. It is named for the brothers Philander and Francis Roots, who first patented the basic design in 1860 as an air pump for use in blast furnaces and other industrial applications. In 1900, Gottlieb Daimler included a Roots-style supercharger in a patented engine design, making the Roots-type supercharger the oldest of the various designs now available.

Out of the three basic supercharger types the Roots is considered the least efficient. However, it is simple and widely used and thus is invariably the most cost efficient. It is also more effective than alternative superchargers at developing compression at low engine rpms, making it a popular choice for passenger automobile applications. Peak boost can be achieved by about 2000 rpm. Much work has been done to improve the efficiency of the Roots type supercharger, but because it does not have internal compression (the design can be classified as just a "blower") it will never have the same potential as the twin-screw type supercharger, or the centrifugal type supercharger.

All supercharger types benefit from the use of an intercooler to remove heat produced during compression.

The Roots design is commonly used on two-stroke diesel engines, which require some form of forced induction since there is no intake stroke. In this application, the blower does not often

provide significant compression and these engines are considered naturally aspirated; turbochargers are generally used when significant boost is needed.
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Old 01-07-2006, 11:45 AM
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Now we are talking modern.
An Old design that has been refined that is broken down into two basic types.

Eaton Supercharger & Lysholm Supercharger


Eaton Supercharger


"Twin Opposed Counter Rotating Screws"


The screws are kept in time by a driveline. A set of gears normally suspended in oil or fed directly from the block. Being fed from the block will keep the temperature more stable as the oil is constantly being cycled and filtered through the engine.



Seen here attached to the intake manifold of a V8 is the Supercharger, Notice the large belt attached to the crank that drives the supercharger. The top Cover or scoop just helps along. This particular car is Fuel injected and Not Carburated, you can see the row of injectors that add the fuel that is required to power this car under boost.



Lysholm Supercharger

"Counter Rotating Male and Female Screws"

The Lysholm supercharger looks similar to a helical Roots blower, but with rotors that are far more twisted, and have a conical taper. The result is that these "screw-type" compressors have an internal compression ratio, making them more efficient in high-boot applications. A Lysholm compressor will continue to compress air as long as it is being turned, even if a bypass valve allows that air to be recerculated. The only way to eliminate a Lysholm compressor's parasitic drag at cruise is to let it stop turning via a clutch. This makes it rather difficult to justify in a economy designed car. This should be only considered when high boost pressures with minimal heat and maximum power are needed. This style of Supercharger has a characteristic "Scream" under load.

Just on a side not this is the style I have selected for my 944 Project as I want High Boost with no heat and do not care about fuel consumption under load.



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Old 01-07-2006, 11:46 AM
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ROTREX

Here is what I could get...





Seems to be just like a Centerfugal but with a clutch as you stated above.

Looks Expensive...
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Old 01-07-2006, 11:46 AM
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Detonation and Pre-Ignition will destroy a motor in seconds. It is very important to remember and to understand when changing Turbo components and increasing boost pressure. I would have writen it myself, but this is a very complete description.

Taken From Wixpidia..

Detonation

The fuel/air mixture is normally ignited slightly before the point of maximum compression to allow a small time for the flame-front of the burning fuel to expand throughout the mixture, so that maximum pressure occurs at the optimum point. The flame-front moves at roughly 110 feet/second during normal combustion. It is only when the remaining unburned mixture is heated and pressurized by the advancing flame front for a certain length of time that the knocking effect occurs. It is caused by an instantaneous ignition of the remaining fuel/air mixture in the form of an explosion. The cylinder pressure rises dramatically beyond design limits. If allowed to persist detonation will cause vibration and damage to engine parts.
Pre-ignition

Detonation, explained above, is a different phenomenon from pre-ignition, which occurs when the air/fuel mixture in the cylinder (or even just entering the cylinder) ignites before the spark plug fires. Pre-ignition is accompanied by a loud hacking noise and caused by an ignition source other than the spark. Heat can buildup in engine intake or cylinder components due to improper design e.g. spark plugs with too low a heat rating or due to maintenance, e.g. carbon deposits in the combustion chamber, or also due to overheating of the air/fuel mixture during compression. This heat buildup can only be prevented by eliminating the overheating (through redesign or cleaning) or the compression effects (by reducing the load on the engine or temperature of intake air). As such, if pre-ignition is allowed to continue for any length of time, power output reduces drastically and engine damage can result.

Pre-ignition may lead to detonation and detonation may lead to pre-ignition or either may exist separately.
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Old 01-07-2006, 11:47 AM
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Compression Ratio

Taken from Wikipedia.

The Compression ratio is a single number that can be used to predict the performance of any internal-combustion engine. It is a ratio between the volume of a combustion chamber when the piston is at the bottom of its stroke, and the volume when the piston is at the top of its stroke. The higher the compression ratio, the more mechanical energy an engine can squeeze from its air-fuel mixture. Higher compression ratios, however, also make detonation more likely.

So based on this if you had three identical 2.0L motors all with different compression ratios, 8:1, 9:1, 10:1. They would all make different power. The 10:1 would be the most powerful but it would also be more prone to detonation. You could plan for and reduce the chance of detonation by changing the fuel, intake temperature, colder spark plugs, retarding timing etc...

The compression ratio is based on atmospheric pressure. Now when you pressurize the intake, the compression ratio does not change, but because there is more air in the cylinder to start with, you have effectively increased the compression ratio. The end result is air and fuel being compressed to a much higher pressure than before. This in itself makes more horsepower because there is more air and fuel to burn, but also, the compression in the piston is higher as well. It's wonderful; you get more power from two factors. The increase in pressure has brought the motor much closer to the detonation threshold. The Higher the boost, the more likely is to detonate. So just as before, changing the fuel, intake temperature, colder spark plugs, retarding timing are all factors. You can sacrifice in the design stage of a motor the base compression ratio for the ability to run a higher boost with the same safety margin in regards to detonation. You will loose off boost performance at low RPM compared to a Higher compression, however, as soon as that higher boost kicks in, you will never miss the lower end. This is a factor with turbos and lag.

The Porsche 944 has a compression ratio of 10:1
The Porsche 944 Turbo has a compression ratio of 8:1

These Engines in their stock form have been designed with the end result in mind. Porsche has selected a HP goal for both, the turbo and boost pressure are designed to work with the timing compression ratio and intercooler.

You can over boost a turbo car a bit without much danger, too much boost without proper supporting mods and you will end up with a burnt piston or a split rod.

Remember to factor in the "Goal" and "Result" in any project.

Here is a High Compression Piston good for N/A Applications..



Low Compression More suited for Forced induction.

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Old 01-07-2006, 11:47 AM
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The Front Mount Intercooler or FMIC is normally the first thing in the car. It normally sits before the radiator as seen here...



Alright, You want to Up the Boost and Up The HP, You have to think first. Every time you change something in a car to get performance, there are other things that will change as well, some (Most) of them are negative.

Oxygen is the only hard thing to put in an Engine...
More Fuel, No Problem,
Bigger Spark, No Problem.

Agreed. So Back to Chemistry.

Air is a mixture of Nitrogen and Oxygen. The Hotter a Gas is (In this case air) The fewer the number of atoms are present in that volume.
So


1 Ft/Cu of air at 100Deg
will have many less molecules than. 1 Ft/Cu of air at Zero Deg.

Just by changing the temperature of the intake, you have made more HP because you have more Oxygen, so you can burn more Fuel.
Easy Fundamental Concept #1.

A Turbo and Supercharger both compress air. The action of compressing the air makes the air much hotter. The amount of heat depends on how efficient the compressor is but it can be calculated. The More pressure the compressor is making the hotter the air becomes.
Easy Fundamental Concept #2.

You want more boost, you get more heat. More heat equals less molecules per volume of air. So as you are compressing more air into the engine, you are not getting the same density of air and are not getting as much oxygen as you should for the volume.

The intercooler is designed to remove the heat caused by compression.
This reduces the negative effect of compressing air and Makes More Horsepower.
Reduces The Likeliness of Detonation.

Pressure Drop

Basically the loss or restriction that an intercooler has.

EG#1. To get 10.0 Psi at the engine after the intercooler the turbo has to push 11.0 Psi before.
That is an acceptable drop.

EG#2. To get 10 Psi at the engine after the Less Efficient intercooler the turbo has to push 13.0 Psi before.
That is not helping. To get the turbo to make the extra 3 Psi, it will be creating allot more heat than EG#1. So this intercooler is not capable for the Volume that is required to move with efficiency. It will eventually heat soak and the intake will start to heat up. OMG! The extra 3 Psi will cancel out with heat. Minimal Gains.

The Intercooler must be capable to move the volume of air with as little pressure loss as possible.


Heat Soak


Heat soak is simply when the intercooler is overwhelmed with constant high heat that it is not capable of dissipating. The longer the turbo makes boost, the hotter the intercooler will get hotter to the point where the air coming in and the air going out of the intercooler are the same. You will get good power for a bit and then it will fall off and you could detonate.

Water To Air Intercooler (Like On the Cobalt SS)

Uses a heat exchanger, Radiator, Pump and Coolant. The Air charge heat is transferred to a heat exchanger and taken to a radiator by the coolant with a pump. Normally used where space is difficult.



Air To Air Intercooler (Like On Most Turbo Tuner Cars)

Like a Radiator except, Air is being cooled in the passages instead of coolant. Air passes through the internal passages and heat is transferred to the ambient air through the metal fins.

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Old 01-07-2006, 11:47 AM
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Alcohol/Water Injection

First, It does work. (So There, I said it)
Second, it should be considered as a Band-Aid for a larger design problem.

http://www.aquamist.co.uk/

The basic idea is that just like a Front Mount Intercooler... If you drop the temperature of the air going in the engine you have done a couple of things...


1. The Air Is Denser. (More Oxygen)
2. The Engine is less prone to Detonation
3. You can run Higher Boost with the same detonation threshold.


The basic idea is that a mixture of Water and Alcohol is dumped into the throttle body under boost. The mixture evaporates and has a cooling effect. It was very common in Supercharged WWII Fighter Planes to promote more reliable operations under emergency conditions... Notice that... Emergency Conditions...

The route of the original problem that caused you to seek the injection would be "Poor Design" of the basic system in question.

FMIC, CAI, More Efficient Compressor either Turbo or Supercharger.

So here is some Physics.

The idea of Forced Induction is to cram more oxygen in the engine.

Colder Air is more Oxygen,
More Air is More Oxygen.
More Air that is Hotter is the same or less Oxygen (closer to detonation too)

For the injection to work it must be dumped into the intake. The Volume of liquid will displace some of the air it is cooling. So the air is colder and denser, but the alcohol and water has displaced some of it, It cancels out a bit.




Abstract Thought Time, This is only an Example to illustrate the concept.

There is no magic in Physics. To get, you must Give too...

It's like changing the pulley on the supercharger to get 10 HP more, but in doing so you have put an additional 5 HP of draw on the belt and the heat is higher so that kills 3 HP too. You get 2 More HP and more strain on the car. Was it worth it, No. Had you just cooled the air more, you would have gotten your 2 HP without changing anything.

10 HP - 5 HP - 2 HP = Whoopee, 2 ****ty HP..

Brian's Take... Look into a more effecient Perminant Intercooler before looking into this idea.

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Old 01-07-2006, 11:48 AM
  #15
Brian 944
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http://www.dipmec.unian.it/disegno/d...ompressore.avi

Here is a link for a Video of a Turbo.

http://www.dipmec.unian.it/disegno/...Compressore.avi

Here is a link for a Video of a Lysholm Supercharger

http://www.dipmec.unian.it/disegno/d...olumetrico.avi

Here is a link for a Video of a Roots Blower.
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