Turbo Size psi/volume

[BillyM]

I'll one up Rob's map, and I'll map out the pressure ratios on a t04e 60trim, that a 5m turbo will consume at ~350hp. The first map is at sea level, the second is at ~14k feet, or .6 atmospheres, as Rob has has used in his explaination. Temperatures are static, and I've not compensated for the effect of reduced pressure at the tailpipe on spool speed.

Actually, the only thing that really has changed at sea level v. the 1+ atmosphere inside of your manifold is absolute pressure.

Barometric compensation - compensates for the density due to altitude if you use it that is. If you do use it, it helps in adjusting for changing exhaust velocity due to the lack of atmosphere hindering the exhaust on it's way out.

Hence why turbo props can go to 20k+ feet and still remain running.

300kpa inside of your manifold stays the same if it is 300kpa @ sea level or 300kpa @ 30k feet.

Your "holy-crap-batman-surging" 60-trim at 14k feet says otherewise...
HAC also compensates for turbo efficiency, don't forget it.
Enjoy,

--billyM

 

[figgie]

I'll one up Rob's map, and I'll map out the pressure ratios on a t04e 60trim, that a 5m turbo will consume at ~350hp. The first map is at sea level, the second is at ~14k feet, or .6 atmospheres, as Rob has has used in his explaination. Temperatures are static, and I've not compensated for the effect of reduced pressure at the tailpipe on spool speed.



Your "holy-crap-batman-surging" 60-trim at 14k feet says otherewise...
HAC also compensates for turbo efficiency, don't forget it.
Enjoy,

--billyM

and you are not telling me anything I don't know.


BTW

you forgot one thing on that nice graph. That is only HALF of the turbo equation. That particular half is the compressor section but where is the turbine section along with the associated A/R? Also you are making a terrible assumption that the pressure ratio inside of the system (which in this case is the motor) is open to atmosphere where it is not.


again, 300 kpa @ 40k = 300 kpa @ 0 feet. How you GET THERE is what changes but the end number is the SAME. Be it by TurboA or undersize TurboB, Turbine, Auxilary power units doing the work, Compressor driven on 3 phase 440v airplane electrical system.

CAPISCE?

***I am feeling generous today.

http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech103.html
Now with all that information, let see equations.

btw no cheating in using google, I myself do not need "graphs", equations only please. and BillyM that graph is nice and all, but like my professor used to tell me, show the work and add the exhaust turbine section that you missed. I "do not know" how you arrived at your conclusion and I can not read your mind to see how you derived your answer. ***

 

[BillyM]

...you sound like a chump, fresh out of a entry-level college chemistry or physics class. Infact, you're probably the asshole who argues with the teacher on, wait for it, symantecs as he's using non-standard methodology to help the class understand a difficult subject. So you have a solid grasp on the physics behind it *claps* (you might not be the only one), now figure out how to help people with it, instead of slinging it around trying to impress others.

You can throw around the "rules" all day long, and it's still not going to help 90% of the people on this forum. I put my information into visible graphs, helpful simulations, and easy to understand "what if" methods for the benefit of the greater majority.

-It is important that people understand that different turbos put different ammounts of air in the motor at the same pressures. This is due to efficiency-related temeperature's effect on the density of air in the cylinder.

-It is important that people understand different elevations cause change in a BIG way of how capable a turbo is in any certain running circumstance. Telling people that 14psia is the same at sea level and 30k feet is "correct" but the way that the general populous perceives that is "my car is turbo, it will make the same power at sea level and 30k feet".

I'm done in this thread, don't worry, figgie will help make this clear as mud for you who are trying to learn something...

--billyM

 

[figgie]

Too much crying because he does not know equations

--billyM

Ahh someone's feeling are hurt!

Shame too as this was a nice thread too!

FYI

Incase you missed it, this is the technical section where you either post facts and items to support facts and not hyperboles & answers or you just mosey right along to other less technical parts of this forum. Crying, throwing tantrums when cornered does not do anything save create noise as with your last post.

Myself, I could care less what you think, assume, guess at who I am or what I do. In the end, it does not affect me in any way, shape or form.

general populous perceives that is "my car is turbo, it will make the same power at sea level and 30k feet".

and then at that point we would correct the "general supramania populous". The "General Populace" could care less how it works.

 

[BillyM]

87witmoreboost was right on the money on the last page... Your incessant ranting over theory, while correct (noone else is incorrect), is tiring. Consider me tired.

People aren't going to get anything out of your method of "help" in this thread, and I won't waste my time playing your game of "ego stroke" because I'm plenty secure in my grasp and knowledge of how this all works and I just flat don't have the time. If you need that kind of attention, you might want to go back to class and argue with the instructor. Atleast he's paid to put up with your kind of personality.

The first person who tells you you're a donkey, you can tell him he's wrong.
The second person who tells you you're a donkey, you can explain why you're not.
The third person who tells you you're a donkey, you might just be an donkey.

--billyM

 

[figgie]

87witmoreboost was right on the money on the last page... Your incessant ranting over theory is tiring. Consider me tired.

The first person who tells you you're a donkey, you can tell him he's wrong.
The second person who tells you you're a donkey, you can explain why you're not.
The third person who tells you you're a donkey, you might just be an donkey.

People aren't going to get anything out of your method of "help" in this thread, and I won't waste my time playing your game of "ego stroke" because I'm plenty secure in my grasp and knowledge of how this all works. If you need that kind of attention, you might want to go back to class and argue with the instructor. Atleast he's paid to put up with your kind of personality.

--billyM

my my. Someone ate a sour bowl or two of stale cheerios today.


I suggest you look my previous history up. I have no ego. I have and will call incomplete statements, ignorant statements etc. Symantecs, no such thing. Typing leaves zero room for interpretation so when I come in and post, is because there was lots of room for interpretation.

Anyway. I don't feel like derailing this thread anymore than what you already did... so exit stage right I go.

 

[Doward]

...you sound like a chump, fresh out of a entry-level college chemistry or physics class. Infact, you're probably the asshole who argues with the teacher on....

You just lost any respect in this discussion you may have had. Resorting to name calling ends your side of the argument rather effectively, in my opinion.

The 'technical engineering theory' as it was called by someone previously, holds completely true. The fact of the matter is there are too many variables (has anyone here even considered the airflow velocity changes in the curves on the IC system? Or pressure drop from the IC? Pressure drop from the filter? Exactly.)

Don't get pissed because someone mentioned there is more to something than an oversimplification presents. I do it all the time, taking the technical and 'dumbing it down' so the average Joe can understand it. Many times I get called on it, that there is 'more than meets the eye' to the subject I'm trying to explain. Those people generally fall into the same category I do - there is RIGHT and there is WRONG. Period. I don't mind breaking out of that mold to help someone else understand a complex subject, however.

That said, this is a TECHNICAL forum. There will be TECHNICAL THINGS PRESENTED. No big deal - PM someone if you don't understand something. I enjoy explaining things in layman's terms

 

[87witmoreboost]

I love/hate this thread.

 

[GrimJack]

Guys, keep it civil. The debate in here was going rather nicely until you had to start taking shots at each other instead of the subject.

 

[Snotcycle]

ok, so its really late but im going to take a stab at explaining this in words everyone can understand.

The next time you go into starbucks to get a fattening pastry and bad coffee, go over to where they keep the milk and sugar. Carefully take a big straw(white wrapper with black on the ends), and a little straw(white wrapper with green on the ends). first blow through the little straw with significant force, then blow through the big straw. to achieve the same given (manifold) pressure--or resistance--with both straws require very different volumetric flows. IE you must blow ALOT more air through the big straw than the small one.

Anyone who does this experiment and does not come to a similar conclusion is either a bumbling idiot and should never have been allowed near a computer. or they are kin of the divine, and i will buy them coffee so they can show me.

/endthread
AMIRITE?

 

[zambini]

never understood th8is relationship until this thread.. so psi is a measure of VOLUME, and the density OF that volume, depending on temerature, allows more or less MASS into a space!

word.

thank you.

 

[Nick M]

Interesting thread.

 

[figgie]

Minus well put this thread to rest.

http://www.supramania.com/forums/showpost.php?p=1142019&postcount=1

That spreadsheeet was created by me to help a couple of the techie folks in this great forum out.

It is configurable for lots of things.

Atmospheric pressure, VE of engine, Engine displacement etc.

play around with it and see the relationship between turbo volume v. power, plenum pressure v. displacement, Turbo sizing v. efficency points. These are rough guesses but can get you really close.

Those turbos in that spreadsheet are the Garrett GT series ball bearing turbos with one inclusion of the HKS T04z replica made by ATP Turbo.

 

[Nick M]

I do it all the time, taking the technical and 'dumbing it down' so the average Joe can understand it.

I don't see a problem as long as it is accurate.