More IC stuff

[QSHIPQ@aol.com]

The esteemed Prof SoC writes the following:

>Scott, this flow rating was done on Spearco's flow bench using a FAA 
>standard day for baseline temps and baro press flow was computed for the
>stock k26 turbo, increase the cfm and it only get's worse expontially.  
>The test was done correctly but more importantly the Test was DONE, 
>Something that you have never done. For the test to be correct you
>cannot do it on a car.

Well, not "exactly."  The EXACT formula for IC efficiency is specifically
more accurate IN the car the IC is put in.  Spearco can give a baseline
efficiency for an IC, but that is the calculated, NOT the actual.   For the
numbers to be correct accurate TO the install we commonly use the following
simple formula:

Temperature rise = Tcompressor outlet - Tambient
Temperature removed = Tcompressor outlet - Tintercooler outlet

So,
Actual IC efficiency % = (Tco - Tio/Tco - Ta) * 100
 
Based on this, I claim that the same IC installed in two different cars
driving at the same speed can yield two different efficiency numbers.  If
that is the case, shouldn't we examine HOW the actual calculations were done
by Spearco?

>to know EXACTLY What is on my car.  What's wrong your crystal ball a 
>little foggy? If you know what's on my car I should'nt have to tell you 
>what I have....  

Maybe if I rephased the question...  I suppose then again one could just tell
us....

>I digress.  My intercooler is air to air, at 26psi and assuming the same
>CFM (Big assumption on your part because when I increase psi I also 
>increase CFM) my pressure drop only increase's to .52psi.  Your above 
>question's show a lack of understanding of the subject matter at hand.

Ok, got that number, the latter opinion.  Given your documented
"understanding" of PT and Bypass Valve operation, I agree best NOT to
digress.  What is the efficiency that you are calculating for the .52 psi
drop?  The question never answered, are we to assume the 96% efficiency the
IC "can be", to be the one in your car?  Given a true "understanding" of ICE,
 are you sure you don't want to correct the statement that "an IC can be 96%
efficient".  Can't it really be more than 100% efficient?

>Let me go through this so that even you can understand it. A turbo map
>is a map of the turbo's performance.  The Turbo only, No intake tract, no 
>airfilter, no intercooler, no exhaust system, Just the turbo on a flow 
>bench. Hopefully compaines like KKK use a standard day for a temp and 
>pressure baseline.  A map is produced showing island's of efficient 
>operation at specific pressure's and CFM's. This can be thought of as 
>"Gross PR". Where are the other losses? Their not in there. Have you ever 
>taken into account the loss becasue of the airfilter?  For you to keep 
>claiming "Net PR" (Boost at the intake that your gauge see's) you need
>to take these into account and they are NOT included in VE.  Using a stock
>2 pass intercooler and 2.0 NETPR a K26 needs to be working above 2.42 
>GrossPR (I'm not even factoring in the loss due to airfilter here, If
>you were to do that your GrossPR would be in excess of 2.9) In the meantime 
>the engine is only seeing the 2.0PR CFM's......... 

Not sure I'm "even" understanding this...   So YOUR efficiency numbers tell
you that those working with 2.0PR mods have a turbo with 2.9PR Before the 2
pass IC?  Really?  That is impressive.  Maybe someone can pop the actual up
and we can look at that some more, very interesting claim... In fact, let's
look at that number on the actual kkk turbo MAP of the audi k26.  2.9PR...
 Ok, then the turbo is spinning at 130,000+++rpm (it's not even listed
actually, I added that curve).  REALLY?  And the efficiency of that turbo is
LESS than 60%.  Really?  That sure is hot air.   So why don't 2.0PR modded
folks blow up their turbos and the hot charge air engine?  2.9PR "gross".....
 That's not even on the MAP (YOUR definition of Gross).  Are we sure that 55%
ICE number is correct?  How can these stage II mods be so darn quick I ask?
 How do we then explain a claim of 72 Hg BY YOU and ME (20psi corrected), on
a Ned stage II box without blowing things up, that's 2.4PR Net (your term,
what is THAT Gross)?  Something doesn't sound right with the above....
  Hmmmmm.  What happens if we accept the pressure drop, but up the ICE?

 Got some numbers or equations to give us all the same conclusions?  KKK does
show ambient pressure and Temp on EVERY map, so "hopefully" indicates one
might not have been seen firsthand.  You might be answering your own question
for the lecture here.  Pressure drop across an IC doesn't necessarily mean
that the IC is "less" efficient, in fact, by construction, one could argue
EXACTLY the opposite (PLEASE REREAD THIS).  Still the baseline isn't here.
  How bout giving us the methodology Spearco used to "test" the IC and get an
efficiency rating at the 50 and 55% rankings you have proposed.  How exactly
did "they" account for the loss of the air filter?  Relevent?  Specifics to
FAA standard might be helpful as well as the definition of "baseline
computed".  How do they figure ambient airflow thru the core?  What are the
assumptions there?

Interesting to note, my "testing" or "claims" are irrelevent here.  Audi did
test the IC IN the 44 chassis car, and that is a published document, TO
accepted standards.  Also interesting to note, THAT document doesn't give the
same conclusion that is claimed here that Spearco did.  So the test isn't the
same....  Or something.  So the tests were ALREADY done, IN the car, does
that invalidate Audis actual published numbers or "Spearcos" out of the car.
 The CLAIM is:

*"Spearco tested the stock IC for Prof SoC with unknown baseline (waiting for
that) and concluded that the audi two pass IC is 55% efficient with a 6psi
pressure drop @ 15psi, and 50% efficient single pass with a 4psi pressure
drop @15psi.  2 pass IC gives a 2.9PR before the IC on a stage II (2.0bar)
mod"

>More correctly YOU Don't have a baseline.  I've done my homework so have
>other's..... Why can't you?
Well, with all due respect sir, not sure many of us take your "homework" as a
baseline anymore.  We still have unanswered questions, and claims that we
can't establish are valid, cuz the homework isn't here.  Why not?  The math,
BASELINE, should establish a target, then the actual indicate the target or
change the baseline.  Few here want to waste a lot of bandwidth on this
subject, me included.  I don't have the same baseline as Prof SoC.  Happy to
plug and play based on them.  Tossing up numbers doesn't add up here, so
where do we go?  Is the "testing" Spearco did available to the rest of us?  

More questions here.  Really, we don't have a baseline for discussion of the
"claims" and "conclusions" drawn.  The numbers presented just don't add up
with math OR actual performance.  I CLAIM, they should.  If not, something
isn't right. Without the methodology and understanding, we could do a lot of
guessing.  Spearco makes good intercoolers and has been established in the
industry for some time.   Maybe I can copy this post to them and get some
techical input from the horse.  OR someone could be more clear for the
benefit of the whole list. 

...  "Whatever" ....  Best get the 2.0bar mods out quick if we are to accept
the above folks, you should have blown up your motor and turbo a long time
ago.

Scott Justusson
'87 5ktqwRS2
'87 5ktq
'86 5ktqw
'84 Urq