Theoretical turbo question

Flight Service wrote:

NordicSaab wrote: I hate engineers. @Flight Service. You are being very narrow minded here. From a layman's stand point, which is all I'm claiming to be, a turbo will do nothing if you heat it. Lets take a Turbocharger (Of any variety) and put it in a kiln at 1000 degrees and see what kind of boost pressure it produces. My hypothesis is it will just sit there. It has heat, why is it not working? A turbo, for all people in the physical world, (and just as Fueled By Caffeine Stated) is a simple energy in and energy out system. Yes there are a million variables. Yes heat makes a difference. I'm done, go run a CAD flow diagram and get more experience while I turbocharge another car successfully.

This is why engineers are mostly introverts. Broad based statements with no accuracy. Try to successfully boost your car by putting the intercooler between the engine and the turbo, cooling the exhaust before it gets to the turbo. See how well it works. I am gonna steal FbC words here. "It's not that simple" I will try to put it in laymens terms. The air moving out of a cold engine, starts the turbo turning. Now we have motion of the turbine. The engine heats up and the turbo starts to spin faster. The heat and pressure expand in the turbo housing causing it to spin faster than the exhaust is coming out of the engine. This gives it the power to add pressure to the intake charge. Because the flow velocity (not mass flow rate) of the exhaust would be the same as the intake if it wasn't pressurized from the heat.

Great picture. I really wish you would bang your head there. You might end up smarter.

I dont think it is simple. but a simple case of energy in energy out with many variables as stated in my earlier post.

You are being very hard headed here. I'm not claiming to be completely correct. I don't claim to be an engineer (despite having the education and working in the profession). I am pointing out that you are being a Berkeleying hard headed self righteous putz.

No one cares about your equations or the class you took. The fact of the matter is most anyone would take someone with hands on physical experience before your white papers and resume any day.

Fueled by Caffeine wrote:

Flight Service wrote: Try to successfully boost your car by putting the intercooler between the engine and the turbo, cooling the exhaust before it gets to the turbo.

Remote mount turbos are effectively what you have described. They work. Now, in my youth I argued about how they were innefficent or not thermodynamically ideal.. But now.. I say. they work but are not ideal. If I follow what you are saying a remote mount turbo wouldn't work because there is little "heat" available.. http://ststurbo.com/why_rear_mount.php

The closer the temp delta gets to zero the less work a turbo can do. You don't get something for nothing.

Here is where the theory really starts to get me, the most efficient ICE is infinitely hot.

Think about that one for awhile.

Flight Service wrote:

Fueled by Caffeine wrote:

Flight Service wrote: Try to successfully boost your car by putting the intercooler between the engine and the turbo, cooling the exhaust before it gets to the turbo.

Remote mount turbos are effectively what you have described. They work. Now, in my youth I argued about how they were innefficent or not thermodynamically ideal.. But now.. I say. they work but are not ideal. If I follow what you are saying a remote mount turbo wouldn't work because there is little "heat" available.. http://ststurbo.com/why_rear_mount.php

The closer the temp delta gets to zero the less work a turbo can do. You don't get something for nothing. Here is where the theory really starts to get me, the most efficient ICE is infinitely hot. Think about that one for awhile.

So.. about 6 years ago.. I went through this same exercise on this very board.. An older engineer played the part I am playing now and you are playing the part of me back in my Holset days.

funny how life repeats itself.

In reply to NordicSaab:

Given I am the guy that works in the field when the techs can't figure out what's wrong and push the changes back to the factory, your opinion is filed appropriately.

Am I hard headed, yes. An shiny happy person, OK, I will own that. The one who knows what he is doing and people trust million dollar decisions based on his input, I am that too.

Fueled by Caffeine wrote: So.. about 6 years ago.. I went through this same exercise on this very board.. An older engineer played the part I am playing now and you are playing the part of me back in my Holset days. funny how life repeats itself.

I think this statement does a good job summarizing this entire argument.

Fueled by Caffeine wrote:

Flight Service wrote:

Fueled by Caffeine wrote:

Flight Service wrote: Try to successfully boost your car by putting the intercooler between the engine and the turbo, cooling the exhaust before it gets to the turbo.

Remote mount turbos are effectively what you have described. They work. Now, in my youth I argued about how they were innefficent or not thermodynamically ideal.. But now.. I say. they work but are not ideal. If I follow what you are saying a remote mount turbo wouldn't work because there is little "heat" available.. http://ststurbo.com/why_rear_mount.php

The closer the temp delta gets to zero the less work a turbo can do. You don't get something for nothing. Here is where the theory really starts to get me, the most efficient ICE is infinitely hot. Think about that one for awhile.

So.. about 6 years ago.. I went through this same exercise on this very board.. An older engineer played the part I am playing now and you are playing the part of me back in my Holset days. funny how life repeats itself.

The more things change the more they stay the same? LOL

Flight Service wrote: The more things change the more they stay the same? LOL

I'm super serious.. This is freaky. Glad I'm no longer in engineering, but I sometimes loathe what I do now. But the pay is 300x better.

In reply to Fueled by Caffeine:

What do you do now?

Flight Service wrote: In reply to Fueled by Caffeine: What do you do now?

It involves selling out and getting an MBA.

Seriously, i wish to know of this magical turbo motor that does the same air movement at a given RPM regardless of load.

Swank Force One wrote: Seriously, i wish to know of this magical turbo motor that does the same air movement at a given RPM regardless of load.

http://www.ebay.com/itm/ELECTRIC-SUPER-CHARGER-UPGRADE-WITH-HP-GAIN-TURBO-HONDA-CIVIC-PRELUDE-ACCORD-/121101507571?pt=Motors_Car_Truck_Parts_Accessories&hash=item1c32365bf3&vxp=mtr

HAHAHAHA!!!

That's pretty much exactly what i had in my head. Or an n/a motor, which, you know... isn't a turbo motor.

Oh lord, it was only a matter of time before those came up - again. Anyone who buys such a device gets what they deserve. And yes, I know your post was in jest.

I'm posting it again, cause it's awesome https://www.youtube.com/watch?v=cbGWgvJN1_8

Most of these posts are correct but overcomplicate matters.

Can you spin a turbo with cold air (tailpipe turbo)? Yes, point a compressed air hose at a turbo and watch.

Can you spin a turbo with hot air (at-engine turbo)? Yes.

Which spins the turbo faster for the same gas volume? The hot gas version. I'll let the married couple here argue about how much faster it spins with the hot gas.

I think the disconnect is interchanging "most work" with "most important."

They aren't the same thing. Even if heat DOES do the most work (I don't know, and i really don't care, i only worry if my EGTs stay above 2000F for an extended period), it won't do anything by itself without flow.

Therefor, flow is most important.

kb58 wrote: Most of these posts are correct but overcomplicate matters. Can you spin a turbo with cold air (tailpipe turbo)? Yes, point a compressed air hose at a turbo and watch. Can you spin a turbo with hot air (at-engine turbo)? Yes. Which spins the turbo faster for the same gas volume? The hot gas version. I'll let the married couple here argue about how much faster it spins with the hot gas.

you pretty much nailed it.

Other than the 'same volume' part.

I think my statement about engineers not being much better than anyone else at explaining ( which != understanding..) how turbos work has pretty much held although i give FBC much credit for concision and relatability beyond that normally demonstrated by professionally inculcated engineering-types.

But the part of this thread where a series of posts are made which overcomplicate some things but show a lack of understanding of relatively simpler concepts is exactly why i said what i said about engineers in the first place, and im pretty sure nobody other than other engineers feels any need to respond when one (or more) start dick-waving their titles/degrees/professional experience. Reinforcing negative stereotypes about engineers etc etc.

Having said that, i hold noone more accountable for this whole thing then myself. When i said it was a rabbit hole i'd rather not go down.. well, i could have just stopped there. I sort of trolled this whole thing into existence. What an ass!