What did you do TO your Bronco Sport today?

[cprcubed]

Just depends on what side of the turbo's compressor wheel you're on. It's "pulling" air from the air filter side and "pushing" air on the downstream side. Cheers!

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[Mark S.]

Really just asking as the above is my understanding. Looking forward to the education if I am wrong.

This video is a great explanation of how a turbocharger works.

 

[Idahobro]

Just depends on what side of the turbo's compressor wheel you're on. It's "pulling" air from the air filter side and "pushing" air on the downstream side. Cheers!

perfect. thanks

 

[Meanderthal]

I'm probably under educated here, but isn't the turbo pushing air and having air pushed to it. My understanding is that a turbo is a passive device so it can't "pull" air, unless it is a procharger hooked up to the accessory drive?

Really just asking as the above is my understanding. Looking forward to the education if I am wrong.

Nope, a turbo is not a passive device. It is not directly driven by a physical connection to the engine, it is driven by the exhaust gasses coming out of the engine. So the exhaust gasses push on one side of the turbo through a bladed impeller wheel and on the same shaft there is another impeller wheel that follows and is in the intake tract. When that impeller in the intake is spun, it creates a vacuum that pulls air through the intake and creates pressure on the outlet side of the turbo. That pressure then pushes air into the cylinders when the intake valves open in the head.

There are some "turbos" that have an electric motor hooked to them, so they don't use exhaust gasses. And a "procharger" is essentially a turbo that is driven through a belt drive and a gear set to get the necessary rpms (10's of thousands of rpms). A supercharger works on a different principal, or principals, but is also usually belt driven.

 

[Idahobro]

Nope, a turbo is not a passive device. It is not directly driven by a physical connection to the engine, it is driven by the exhaust gasses coming out of the engine. So the exhaust gasses push on one side of the turbo ...

Hmmm. Not to be argumentative, but I believe that is the very definition of a passive device. Meaning is doesn't work without the exhaust gas coming out of the engine (er go passive).

Probably a "you say potatoes..." argument.

 

[delm]

Hmmm. Not to be argumentative, but I believe that is the very definition of a passive device. Meaning is doesn't work without the exhaust gas coming out of the engine (er go passive).

Probably a "you say potatoes..." argument.

Correct. I hate always being on the other side of these things from Meanderthal, but you are correct: A Turbo does not depend on power from the engine to work, which is the definition of a passive device (where a supercharger is belt-driven, meeting the definition of an active device).

But yes - "potatoe". At the end of the day, it won't do much without a running engine.

 

[Mark S.]

A Turbo does not depend on power from the engine to work...

But it does depend on engine power. It's power that's otherwise wasted out the tailpipe, but it's power nonetheless. It's the same kind of energy that powers a turbine engine. It was genius to realize the energy wasted out the exhaust system could be used to power a compressor.

At the end of the day, it won't do much without a running engine.

Which is the very definition of a non-passive device.

 

[delm]

But it does depend on engine power. It's power that's otherwise wasted out the tailpipe, but it's power nonetheless. It's the same kind of energy that powers a turbine engine. It was genius to realize the energy wasted out the exhaust system could be used to power a compressor.


Which is the very definition of a non-passive device.

Don’t know what to tell you. A turbo is a passive device that works indirectly from the engine.. It’s not powered by electricity, or the engine. It is classified as a passive device.

“Components incapable of controlling current by means of another electrical signal are called passive devices. Resistors, capacitors, inductors, transformers, and even diodes are all considered passive devices”

turbos are passive devices.

And no - what you quoted from me is not the definition of a non-passive device.

 

[Meanderthal]

Hmmm. Not to be argumentative, but I believe that is the very definition of a passive device. Meaning is doesn't work without the exhaust gas coming out of the engine (er go passive).

Probably a "you say potatoes..." argument.

Potatoe, like Delm said, it won’t do anything without exhaust. I interpreted your post as basically saying a turbo does nothing. I don’t know what you thought pushed the air to the turbo. I just had a discussion with Delm about how a turbo creates a relatively consistent vacuum in the intake.

It does take some power from the engine to run the turbo. There is more back pressure in the system which means that during the exhaust stroke, the engine has to push harder to get the exhaust out of the engine. The turbo more than makes up for the power required. To date it is the most efficient of the turbo/pro charger/super charger grouping of power adders. The only thing I can think of right now that is more efficient is nitrous. As efficient as the turbo is, it does still take some energy to make it work.

So, is that passive? I guess it is up to you.

 

[Meanderthal]

But it does depend on engine power. It's power that's otherwise wasted out the tailpipe, but it's power nonetheless. It's the same kind of energy that powers a turbine engine. It was genius to realize the energy wasted out the exhaust system could be used to power a compressor.


Which is the very definition of a non-passive device.

A turbine engine is only slightly related to what is happening in a turbo. The turbine engine does the compression, ignition, expansion, and exhaust. The exhaust of a turbine engine is somewhat similar to a turbo.

The turbo isn’t using heat to make it work. I think that a lot of people believe that, but it isn’t really the truth. It uses hot exhaust gas but it isn’t harvesting that heat to create kinetic energy. There are some things people do to try and keep heat in the exhaust, the reason for that is that if it loses temp it will also lose pressure. You want as much of the exhaust pressure to remain as you can get, so you want to keep that gas as hot as possible.

 

[Idahobro]

Potatoe, like Delm said, it won’t do anything without exhaust. I interpreted your post as basically saying a turbo does nothing. I don’t know what you thought pushed the air to the turbo. I just had a discussion with Delm about how a turbo creates a relatively consistent vacuum in the intake.

It does take some power from the engine to run the turbo. There is more back pressure in the system which means that during the exhaust stroke, the engine has to push harder to get the exhaust out of the engine. The turbo more than makes up for the power required. To date it is the most efficient of the turbo/pro charger/super charger grouping of power adders. The only thing I can think of right now that is more efficient is nitrous. As efficient as the turbo is, it does still take some energy to make it work.

So, is that passive? I guess it is up to you.

LOL. Yes, I know a turbo runs off the exhaust.

Yes, I know it takes more power from the engine to spool the turbo, and yes, I know there is a net gain from a turbo. I have a 6.7 PSD.

Yes, that is passive.

"
FUNCTION OF LOAD, NOT ENGINE SPEED

The energy that turns a turbocharger’s turbine wheel comes from the hot exhaust gas leaving an engine’s cylinder. The turbocharger is passive since it responds to a much lesser extent to engine crankshaft speed than exhaust temperature. That is why you will hear the turbo spin up when the engine is loaded, even though there may be little to no increase in engine speed.

As the load on the engine increases, so do the exhaust temperature and its velocity. When the exhaust leaves the port of the cylinder head, the inert gas experiences isentropic expansion. This means without temperature change.

The hot and expanding gases are forced into the turbine housing and act on the turbine wheel in the same manner the flow of a river would have had on an old grist mill. The compressor wheel then feeds air to the intake manifold under pressure. The result is an increase in VE, power, and reduced emissions."

 

[Meanderthal]

LOL. Yes, I know a turbo runs off the exhaust.

Yes, I know it takes more power from the engine to spool the turbo, and yes, I know there is a net gain from a turbo. I have a 6.7 PSD.

Yes, that is passive.

"
FUNCTION OF LOAD, NOT ENGINE SPEED

The energy that turns a turbocharger’s turbine wheel comes from the hot exhaust gas leaving an engine’s cylinder. The turbocharger is passive since it responds to a much lesser extent to engine crankshaft speed than exhaust temperature. That is why you will hear the turbo spin up when the engine is loaded, even though there may be little to no increase in engine speed.

As the load on the engine increases, so do the exhaust temperature and its velocity. When the exhaust leaves the port of the cylinder head, the inert gas experiences isentropic expansion. This means without temperature change.

The hot and expanding gases are forced into the turbine housing and act on the turbine wheel in the same manner the flow of a river would have had on an old grist mill. The compressor wheel then feeds air to the intake manifold under pressure. The result is an increase in VE, power, and reduced emissions."

Okay, if you want to call it passive then you are free to do so. Potato!

Have you come to the conclusion that the turbo can pull air through the intake? That was truly the crux (at least in my mind) to your post.

 

[Idahobro]

Have you come to the conclusion that the turbo can pull air through the intake? That was truly the crux (at least in my mind) to your post.

Yep, for sure. Can't believe I spaced that. You are definitely correct. Good discussion.

 

[Tigger]

I haven’t understood a word in the last 15 posts but this consistent mentioning of potatoes is making me hungry.

 

[jhnvan]

Installed my new wheels and tires, roof tent and half basket. skid plates and suspension lift next.

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