Hermosa

Okay. I am hoping to get a good explanation of the whole concept of turboing. Now the part I am interested in first is the thing that you attach to the exhaust to drive the turbo.

I am trying to figure out the following: (Don't laugh at the newbie)

What is that piece called that you attach to the exhaust? (I believe it is just the other side of the turbo but it has to have a name.)

How easy is it to attach? Would it take a lot of work?

Any other special hardware needed to get the thing to pump air or will this thing alone just start pumping air? (I know that there are other components needed to control the flow.)

I know there is a lot to a turbo but I would like to learn the basic mechanics of this piece to start off.

Help make me and others interested in turbos so we can be turbo junkies too.

awj

I am by no means an expert - but I love to talk about these because everytime I do - I learn more.

Bare bones -

There is an exhaust manifold that is specific for running turbo. On an in line with single turbo - all runners will come together at a flange. This flanger mates to a flange on the turbo. This is where the two are bolted together.

The V8 would have a exhaust manifold on each side - four runners going in to a flange where turbos would be mounted.

The exhaust gas runs through these manifolds into the turbo where a turbine is spun. The gas spins the turbine and makes its way on out the exhaust wich may have a larger diameter out the back.

The turbine spun from the exhaust side is on a shaft that spins another turbine on the other side of the turbo. This turbine is taking in an intake charge through an intercooler - or atmosphere. This turbine pressurizes the intake air and sends it up through the throttle body under pressure.

Into the intake manifold, now in the combustion chamber there is a much more dense amount of air. With some increased fuel flow, (regulator, pump, bigger/extra injectors, ecu) the air fuel mixture can be increased proportionally. This gives your increase in power.

Now if you have the air and not the fuel you run lean and risk detonation. If you have the fuel and not the air you run rich and foul - you have no combustion.

There are other issues, relieving pressure when the demand is not there - blow off valves/waste gates. Intake temperature - intercoolers. Compression and others.

Maybe Lex or Jeff have some input on this.

SC300TURBO

iTrader: (2)

pretty good post there...im impressed......good basic description.....there is alot more to controlling fuel...air...and electronics involved.......but a good mechanical description.....Hermosa...turboing isnot easy and theres not current turbo set up for the sc400....Jeff

Lex Luthor

Sounds good to me, awj, I should see if you feel like answering the twenty e-mails I get a day with tech questions.......

awj

***** man - I just post when I'm bored. Now, if that could make mon$y.

Hmmmm.

Bean

iTrader: (1)

close but a little off

here's the fix:

the exhaust turbine spins up the compressor side wheel (what awj said), the compressor sucks in air from the atmosphere; it does not suck in air from an intercooler... the other hair dryer looking part on the compressor housing itself is where the air is shoved through... this air is shoved through an intercooler (or none at all and just a tube) nevertheless, it ends up hitting the throttle body and intake manifold and is 'forced' in; this constant pressure and higher and higher rpms from the exhaust side compress the air into the intake manifold

the compression leads to more air being shoved into the cylinder; mix more fuel with that and ignite and BOOM!!! bigger explosions

awj had 99% of it right though; it was just that intercooler part

there are a LOT of dynamic things that affect turbocharges like air temperature; the way the blades are cut on both the compressor and exhaust turbine, etc

A book called 'Maximum Boost' written by Corky Bell is THE BIBLE for turbo people. I suggest you buy it. Its very informative and easy to read

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controlling the flow

the only way to control boost reliably is by using a waste gate; external wastegates are easier to explain; so i'll explain one of those...
To control boost you have to limit the amount of air that spins on the exhaust turbine so it won't spin too fast. (faster spin = more boost). To control this; on an exhaust manifold; you can have a tube BEFORE or right in line with the turbo exhaust side; on this tube is a wastegate; the wastegate has a spring; for when enough pressure builds up, it will open up and allow the air to pass through it without passing through the exhaust side of the turbo; thus controlling the amount of air that hits the exhaust turbine blades... air like most things in physics will take the path of least resistance; that being the turbo; until the pressure builds up enough to where the spring opens and allows air to flow right out into the atmosphere (or directly into the exhaust system, both ways bypassing the turbo)

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blow off valves

blow off valves protect your turbo from compressor surge. when letting off the throttle, there is an excess amount of pressure in the intake tract... this pressure HAS to go somewhere; without a blow off valve it goes directly back into the compressor side of the turbo and causes it to stop spinning VERY quickly... this stress can destroy a turbo.
a blowoff valve can detect when there is a sudden change of pressure to vacuum in the intake manifold... it is located on the intake pipe after the intercooler and before the throttle body usually...
when it detects the change, it will instantaneously open and allow all that extra air to discharge into the atmosphere it makes a cool sound that sounds like this: pppppphhhhhhsssshhhhhhtttt... and there are many variances of sound; i happen to prefer the TurboXS Type-H BOV. others prefer the HKS SSV

awj

Maximum Boost *runs to book store*

JBrady

Some good information posted here. Let me add my take.

Turbo-Supercharging is the actual correct term. Supercharging is the act of forcing MORE air MASS into an engine than it can flow using the Natural Pressure of the atmosphere. Belt driven superchargers and turbo driven superchargers are called Compressors. As stated above turbos get their name from the exhaust turbine side of the unit. This uses exhaust heat and flow force to supply power to a shaft that is supported by bearings that spins the compressor.

When you compress air it becomes hotter. If you place a cooler between the compressor outlet and the engines thottle body (intercooling) you reduce the thermal load on the engine. This allows more mass to be used and makes more power.

As stated above, boost is controled with a wastegate. This device allows some of the exhaust energy to by-pass the turbine in a controlled manner and such limits boost.

Blow off valves eliminate compressor surge. Compressor surge does NOT stop a compressor from spinning. It does slow it down. It is stressful. It is like putting on air brakes.

quick

Go memorize this and you'll have a good introduction:
http://www.howstuffworks.com/turbo.htm

Bean

iTrader: (1)

yeah i didn't mean stop spinning completely; it just slows down FAST... very stressful