quick garrett turbo question... opinions

[crushers]

oh, a man with common sense...nice.

personally i have no problem with the discussions that go on, although they do get tiresome. pulling numbers out of the air and trying to make sense just does not work but fun to watch. in the end 'real life' will dictate if the numbers are faulty or applicable in a said application.

as for exhaust diameter and feeling of more power... bingo.
of course going from a 2" exhaust up to 2 1/2" increases the air flow 25% which is adaquate, going up to 3" will increase the air flow 50% from stock which is all you really need and anything above that is just a penis extension... this is on a BJ, PZJ and HZJ.. the newer engines i have not had an oportuinity to work on so i will leave the assumptions to the engineering gurus.

Guys, As an outsider (not involved in this discussion) who is following this thread to see how this turbo affects the performance and reliability of this case, I have one conclusion.

Question for Crushers. If a higher diameter exhaust will allow faster spool, wouldn't this account for the 'feeling' of more power?

 

[Otterav]

You'll find the relevant equations in any good thermodynamics text book. Turbine (brayton) cycle.

The 3B may have 10% more capacity than a supra engine, but it has only 50% of the rev range.
Which gives you 55% of the airflow.

Sounds just like a turbine engine
Brayton cycle - Wikipedia, the free encyclopedia

A 12th grade definition:
Turbine Engine Thermodynamic Cycle - Brayton Cycle

A littl something from MIT:
3.7 Brayton Cycle

Sounds just like a diesel engine:
Joule's cycle - definition of Joule's cycle by the Free Online Dictionary, Thesaurus and Encyclopedia.

Sounds like a refrigerator:
The Joule cycle

Yes 50% of 5400RPM is 4100RPM:
Toyota M engine - Wikipedia, the free encyclopedia

The difference between us is, I readily admit that my knowledge base is limited to practical experience and am willing to use existing knowledge and technology, ie Toyota. I do not use inappropriate technical concepts, knowing that most will not research the obscure and most often improper use of these concepts. After researching the Diesel Reference Handbook, I cannot find one of his equations as he lists them. The reasons I choose to call B.S. is, inaccurate information qualified with incorrect application of misc. theories is wrong on so many levels, I cannot even list them. I am not a turbocharging expert(nor is he on any level), nor do I claim to be, this subject, as in life, lends itself to hiring qualified talent for a nominal fee to solve technical questions. In short do your own research.
eric

 

[lshobie]

Atta boy Eric.

 

[Otterav]

if I remember right this is the 2nd, 3rd, heck maybe 4th time this has been going on.....Cool for a while but from my point of view nothing is ever settled.

I think they are more then likely both right on somethings and both wrong on somethings. God forbid we ever admit anything like that.

If I can get you and others to question everything posted here and on the internet, that will settle "it" for me. He comes across as a "knowitall", which is difficult when the "knowitall" is right, and totally bizarre when the information is only 1/2 correct at best. Go to Pirate and Toyotadiesel forums and read his posts there.
eric

 

[Otterav]

OhhhOOOhhh,
Check the inventors:
The helmet that could turn back the symptoms of Alzheimer's | the Daily Mail
eric

 

[Dougal]

Sounds just like a turbine engine
Brayton cycle - Wikipedia, the free encyclopedia

A 12th grade definition:
Turbine Engine Thermodynamic Cycle - Brayton Cycle

A littl something from MIT:
3.7 Brayton Cycle

Sounds just like a diesel engine:
Joule's cycle - definition of Joule's cycle by the Free Online Dictionary, Thesaurus and Encyclopedia.

Sounds like a refrigerator:
The Joule cycle

Yes 50% of 5400RPM is 4100RPM:
Toyota M engine - Wikipedia, the free encyclopedia

The difference between us is, I readily admit that my knowledge base is limited to practical experience and am willing to use existing knowledge and technology, ie Toyota. I do not use inappropriate technical concepts, knowing that most will not research the obscure and most often improper use of these concepts. After researching the Diesel Reference Handbook, I cannot find one of his equations as he lists them. The reasons I choose to call B.S. is, inaccurate information qualified with incorrect application of misc. theories is wrong on so many levels, I cannot even list them. I am not a turbocharging expert(nor is he on any level), nor do I claim to be, this subject, as in life, lends itself to hiring qualified talent for a nominal fee to solve technical questions. In short do your own research.
eric

A turbo is a gas turbine, it uses an internal combustion engine as the heat source. If you can't make that connection then I'm afraid that's where your limits lie.

The page you linked from MIT explains all the formulae you need and even displays the results on a pressure/volume diagram. If you can't apply them then maybe you should say so and maybe even ask for help.
Suffice to say, googling thermodynamics will probably not help. You've proved that.

The Joule Cycle is not the diesel cycle, it is closer to the stirling cycle. You're a long way off track to find that one.

The 7M engines rev way past 5600. 5600 is where the stock max power is found. You've said yourself you don't take your 3B past 2800rpm.

Nice to know there's a Dr Dougal out there. But I don't see what he has to do with me or turbochargers.
There doesn't appear to be a Dougal on the toyotadiesel forums.

 

[Tapage]

On a side note for this thread ..

2.5" factory exhaust are not the same as 2.5" straight pipe exhaust .. and I thought if you go from factory 2.5" to 3" short straight pipe should archive little more than 25% of improve ..

In a month I will post some experiences based on my test that I'm doing in my 1HD-T engine ..

 

[crushers]

well, yes, you are correct
the factory exhaust has bend and criped section so in theory you are correct. my post was a standard exhaust shop bent 2.5 over a stock bent 2" which is 'roughly' 25% gain in flow but a mandrel bent exhaust will be a larger improvement in flow

On a side note for this thread ..

2.5" factory exhaust are not the same as 2.5" straight pipe exhaust .. and I thought if you go from factory 2.5" to 3" short straight pipe should archive little more than 25% of improve ..

In a month I will post some experiences based on my test that I'm doing in my 1HD-T engine ..

 

[Otterav]

A turbo is a gas turbine, it uses an internal combustion engine as the heat source. If you can't make that connection then I'm afraid that's where your limits lie.


The page you linked from MIT explains all the formulae you need and even displays the results on a pressure/volume diagram. If you can't apply them then maybe you should say so and maybe even ask for help.
Suffice to say, googling thermodynamics will probably not help. You've proved that.

The Joule Cycle is not the diesel cycle, it is closer to the stirling cycle. You're a long way off track to find that one.

The 7M engines rev way past 5600. 5600 is where the stock max power is found. You've said yourself you don't take your 3B past 2800rpm.

Nice to know there's a Dr Dougal out there. But I don't see what he has to do with me or turbochargers.
There doesn't appear to be a Dougal on the toyotadiesel forums.

Since you will not read:
The Brayton cycle is a constant-pressure cycle that describes the workings of the gas turbine engine, basis of the jet engine and others. It is named after George Brayton (1830–1892), the American engineer who developed it, although it was originally proposed by Barber in 1791. It is also sometimes known as the Joule cycle. The Ericsson cycle is also similar but uses external heat and incorporates the use of a regenerator.

I think you are now showing your limits, a turbocharger is not a gas turbine engine. This shows the extent of your VOODOO engineering, I have been an aircraft mechanic 20+ years, and Nancy boy, the only similarity there is an compressor and exhaust turbine. Last time I checked internal combustion covers quite a few types of engines. Your "connection" is sketchy at best. I am afraid you are showing your limits.

 

[Dougal]

I think you are now showing your limits, a turbocharger is not a gas turbine. This shows the extent of your VOODOO engineering, I have been an aircraft mechanic 20+ years, and Nancy boy, the only similarity there is an compressor and exhaust turbine. Last time I checked internal combustion covers quite a few types of engines. Your "connection" is sketchy at best. I am afraid you are showing your limits.

Let's see.
Turbine, check.
Compressor, check.
Common shaft joining compressor to turbine, check.
Air inlet, check.
Exhaust outlet, check.
Heat, source, check.

Well it appears the parts are all there. How about the function.

Working fluid is air, check.
Air in is compressed, check.
Air is then heated by combustion and fed to turbine, check.
Heated air and combustion products flow out through turbine, check.
The power extracted in the turbine turns the shaft to power the compressor, check.

Well it appears a turbo is indeed a gas turbine. In fact the internet is full of stories of people converting automotive turbos into stand-alone propane powered gas-turbines. Mostly for amusement rather than anything practical.
We can even look at an interesting French tank called the SACM Hyperbar.
Army Technology - Leclerc - Main Battle Tank

VOODOO engineering has a nice ring to it, I wonder if anyone has trademarked that yet?

 

[Otterav]

You'll find the relevant equations in any good thermodynamics text book. Turbine (brayton) cycle.

The 3B may have 10% more capacity than a supra engine, but it has only 50% of the rev range.
Which gives you 55% of the airflow.

The Brayton cycle is a constant-pressure cycle that describes the workings of the gas turbine engine, basis of the jet engine and others. It is named after George Brayton (1830–1892), the American engineer who developed it, although it was originally proposed by Barber in 1791. It is also sometimes known as the Joule cycle. The Ericsson cycle is also similar but uses external heat and incorporates the use of a regenerator.

You were the one who brought up the Brayton cycle. I researched it and proved your VOODOO engineering is truly in your head.
eric

 

[gerg]

I disagree Otterav. If you look at a gas turbine (Compressor, combustion chamber, turbine), a turbocharged engine runs off of the same cycle. Granted that the engine (combustion chamber) is more complicated than in a turbine, the turbo's turbine does draw from the exhaust gases to run the compressor that in turn feeds the engine air.
Check this out. A turbocharger that looks strikingly similar to a jet engine. I don't think there is any vodoo, just a different application of the principal. TechNudge DIY Jet Engine

And on a side note... does anyone know what the combustion chamber volume is for a 3B?

G

 

[Dougal]

The Brayton cycle is a constant-pressure cycle that describes the workings of the gas turbine engine, basis of the jet engine and others. It is named after George Brayton (1830–1892), the American engineer who developed it, although it was originally proposed by Barber in 1791. It is also sometimes known as the Joule cycle. The Ericsson cycle is also similar but uses external heat and incorporates the use of a regenerator.

You were the one who brought up the Brayton cycle. I researched it and proved your VOODOO engineering is truly in your head.
eric

Wikipedia doesn't count as research.
The joule cycle is not the brayton cycle, but to a layman the similarities may cause confusion.

The ericsson cycle model is based on isothermal compression (no charge heating), the Brayton on adiabatic (air heats as it compresses).
I'd expect everyone here to know that turbo compressors cause air to heat and hence understand why the Brayton cycle is the applicable one.

 

[gerg]

OK OK OK... I want a jet powered canoe!
Untitled Document

So does 42cc sound about right for a 3B combustion chamber volume?

Thanks
G

 

[Dougal]

And on a side note... does anyone know what the combustion chamber volume is for a 3B?

G

That's an easy one.

Bore = 102mm
Stroke = 105mm
So Displaced volume = 858cc
Comp ratio = 20:1
So clearance volume = 857/21 = 40.8cc.

Total volume = 899cc

 

[gerg]

Ahh thanks. I wasnt sure if I divided by 20, or 21.
G

 

[Otterav]

Wikipedia doesn't count as research.
The joule cycle is not the brayton cycle, but to a layman the similarities may cause confusion.

The ericsson cycle model is based on isothermal compression (no charge heating), the Brayton on adiabatic (air heats as it compresses).
I'd expect everyone here to know that turbo compressors cause air to heat and hence understand why the Brayton cycle is the applicable one.

Again discounting anything that goes not fit into VOODOO engineering principals.
Whatever
eric
What part of this basic theory don't you understand?
Ideal Brayton cycle:

* isentropic process - Ambient air is drawn into the compressor, where it is pressurized.
* isobaric process - The compressed air then runs through a combustion chamber, where fuel is burned, heating that air—a constant-pressure process, since the chamber is open to flow in and out.
* isentropic process - The heated, pressurized air then gives up its energy, expanding through a turbine (or series of turbines). Some of the work extracted by the turbine is used to drive the compressor.
* isobaric process - Heat Rejection (in the atmosphere).

Actual Brayton cycle:

* adiabatic process - Compression.
* isobaric process - Heat Addition.
* adiabatic process - Expansion.
* isobaric process - Heat Rejection.

 

[gerg]

Holy crap I think im deaf now!
I say victory goes to the guy who can use a word with the most syllables in a sentance correctly.

So if there is heat loss across a turbochargers turbine, I assume that some of this heat is soaked into the turbo itself, and some is transfered into mechanical energy, and the rest dumped out the exhaust.
Would it make sense in a compound turbo set up to have the larger turbo first with the smaller turbo second in the exhaust stream? That is assuming there is less potential energy (heat) available for the second turbo to work off?

Ohh and by the way, I just love all you guys. Big hugs for everyone
G

 

[Dougal]

* isobaric process - The compressed air then runs through a combustion chamber, where fuel is burned, heating that air—a constant-pressure process, since the chamber is open to flow in and out.

And the prize for the biggest letters goes to.......

You'd better tell us what problem you have with that description of isobaric?
See turbo operating conditions often result in backpressure and boost being equal pressure.

When they don't you simply change the pressure at that part of the cycle. It's not that difficult.

Time to update my sig too.

 

[joshoisasleep]

Wow I can't wait til I can get around to reading the last 2 or 3 pages of this thread later tonight. I had no idea it had exploded so much... my own thread!

Just to clarify, I haven't been arguing either side, know nothing about turbos, and am stupid enough to drive a newly installed one cross country loaded to the gills in high heat with no egt or boost gauge. I look forward to voicing my opinion!