[s-cars] An interesting FMIC "fact" (?)

[QSHIPQ at aol.com]

Gary:
You are taking a lot of things at face value.  For very little money, you can 
put this data in perspective.  I've done a lot of testing on RS2 with stock 
cores, and I find those numbers to be more than a bit off.  That said, testing 
requires that one somehow account for heat soak, or at least stabilize temps 
before actual measures.

The "most advanced kkk k26", does this have a map?  Have you done any actual 
testing of it to make sure that it's all you were told it is *on* the 20vt 
motor?  I'm not at all convinced that any turbo is automatically better than any 
other without some sort of measure of it at applied to the 20vt.  A lot of 
factors dictate the definition of that (dare I say measures?), hence my 
speciously applied commentia.  WRT "all the data that exist WRT S4/S", I don't at all 
think there is that much.  Eventually needs to be done?  Ok, no problem there.  

WRT reverse engineering.  Be careful applying any CO mafia type as any type 
of baseline, maybe if you live in CO.  Again, I only encourage you guys to use 
your own list to help your own list.  Other folks numbers aren't yours yet.  I 
enjoy calculations as much as the next guy, however, premise and data are 
missing from the arguments.  Spearco as expert testimony to the UrS IC is ok I 
guess, but only if you have sent out the URS IC to Spearco for testing (they do 
that btw).  Without that test, I dare say, what Spearco gives you is the same 
as Corky Bell gives you, very general guidelines.  Take them and test what you 
have.  That dictates need.  I'm still pretty convinced that at 100USD/HP for 
8% might get me looking other places first.  Heck Corky argues that a thicker 
IC isn't an autogain (Hap) and that top and bottom feeders are better than 
side to side.  Both appear to have data conflict.

Argue that you "want" it fine.  Argue that 'data' supports any of this, needs 
more.  Increase of 'n' seems a good value.

Just my .02

Scott Justusson
QSHIPQ Performance Tuning


In a message dated 2/27/2004 7:27:38 PM Central Standard Time, 
gary.m.lewis2 at boeing.com writes:
Scott,
To my knowledge I am running the most advanced KKK K26 in the world that is 
outside of a full race program, i.e., commonly available to 
Joe-Schmuck-Off-The-Street(that would be me).  The compressor wheel and housing are currently 
being used in some Porsche racing programs (and NOT the RS2).  Cody has the same 
turbo.  I have been told that the next step for me is either a bigger turbo 
(like a hybrid e,g, Garrett, or bigger KKK with custom spec compressor wheel), 
or, for example, have a titanium turbine wheel, shaft, and compressor made to 
fit what I currently have, which is SERIOUS money.  In other words, the 
argument that Cody and I need a better turbo is specious given what we have (well, 
Hap does make fun of it, but, He's Hap, He can.  MLP could, but he doesn't).  
Bigger maybe, but not better. 

I do agree that the 4 sensor approach is correct, awesome data, but it isn't 
necessarily the most practical given all the data that exist WRT URS4/6 IC.  
Eventually needs to be done, Hap probably should if he hasn't.  Some positives, 
with just 2 sensors aft of the turbo compressor, you can tell the approx 
turbo efficiency by boost psi, turbo-out air-temp, ambient and altitude.  I'm not 
going to do the final two (well one really) aft of the IC right now until I 
install the IC since I already have the IC, happy with the idea of 25 hp, and I 
want to spend the additional money on other stuff instead of 2 more sensors.  
Also easier to install the temp probe into aluminum pipe...

In terms of currently published data, the stock IC efficiency is easily 
reverse-engineered:
1. A comparable Spearco IC Flow-Chart for - The Stock IC, and the IC I have, 
which is more efficient than the one Amoroso used.
2. The increase in flow that nets 25hp and 400rpm reduction in max boost 
achieved.

Doing the above nets me:

a comparable IC to ours has ~ 4psi pressure loss at 24 psi, efficiency is 
less than 50%.  What 50% means is that if ambient is 70F, RS2 turbo exit temps at 
28 psi and 60% efficiency, the exit temps are 381F.  (381F-70F) * (1-.5) + 
70f = 225.5F

Contrast that with a properly sized FMIC.  Pressure drop is less than 1/2 
psi.  Efficiency is over .8 (80%!!!!) at 20 mph.  So an RS2 turbo at say 25 psi 
(1 psi over requested of 24 psi) is at 72% efficiency, exit temps are 309F.  
(309F-70F)* (1-.8) + 70F = 132.8F.  It is almost HALF as cool as stock.  Also, 
making 25 psi happens A LOT earlier than 28 psi, so pressure drops also create 
more power thru lower rpm torque.

You stated that the stock IC is very efficient.  I agree, at 15 psi on a 
2.2liter motor it is wonderfully efficient.  I hate the placement, but that is 
another discussion.  At 24 psi, it is a whole completely different ball game.  No 
IC in the world I know of can be perfectly sized at one boost level, and 
still be perfectly sized when increasing the boost 63%( yikes !!!!!!!!!!!).  
Spearco states that the efficiency ON ALL IC's drops at least 30% from 10 psi to 20 
psi. That's a large drop.  The last 4 psi, now really HOT, probably add 
another 20%.  In other words, the 50% efficiency I used above was generous.

Gary Lewis