Im justas lost as you dog

 

Just in case anyone was interested.

This is Corky's latest website where you can purchase the books mentioned in this thread. Also a wonderful place to pick-up some intercooler theory as well. I got a signed copy of Maximum Boost Art.

http://www.bellengineering.net/

 

Hey guys,

It is almost 3 years since I first wrote this how-to. At the time I wrote it all I was able to use for reference was my book Maximum Boost. Until today, I couldn't find anything else on the net that said how to read a compressor map. While doing some research on how to swap compressor housings I found this very detailed explanation by Garrett on how to read a compressor map.

http://www.turbobygarrett.com/....html

 

Nice! Thanks. I will be studying this for a bit.
I really like technical stuff like this!

 

Dang... nice input.

 

PRESSURE RATIO:
(14.7 + amount of boost) / 14.7 = PR
so to figure out the PR for 10 PSI
(14.7 + 10) / 14.7 = 1.680 PR

Displacement:
cubic centimeters X 0.061 = cubic inches (U.S.)
1599cc X 0.061 = 97.539 ci


CFM: N/A, 100% VE
(RPM X Displacement) / 3456 = CFM
(8000 x 97.539 = 780312) / 3456 = 225.784722 CFM

CFM: w/BOOST, 100% VE
(RPM X Displacement) / 3456 X pressure Ratio = CFM
(8000 x 97.539 = 780312) / 3456 X 1.680 = 379.3183 CFM

if you want to add in VE just CFM X VE = adjusted CFM
379.3183 X .90(90%VE) = 341.3865 adjusted CFM


pounds per minute (LB/MIN):
@ 48 degrees F : (CFM * 0.078125) = LB/MIN
@112 degrees F : (CFM * 0.070318) = LB/MIN
@175 degrees F : (CFM * 0.06251) = LB/MIN

N/A B16: 225.784722 CFM X 0.070318 = 15.87 LB/MIN
turbo B16 @ 10psi: 379.3183 CFM X 0.070318 = 26.665 LB.MIN

that should help people to calculate #2 in the how too. all of this information is stolen in an atempt to consolidate. i'm not real clear on how to adjust these numbers for the added VE of the boost pressure or if there is even a need. maybe some one could break it down "barney level" hope this helps.

here is a nice link to the gt maps just click on the turbo you want to check out.
http://www.turbobygarrett.com/....html


i'm stoked, 15 psi will land me right dead in the center of my gt2871's map, but i'm sure i screwed something up.

Modified by abnaasefmb at 2:54 AM 10/2/2005


Modified by abnaasefmb at 5:19 AM 10/2/2005


Modified by abnaasefmb at 5:23 AM 10/2/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by abnaasefmb &raquo;</TD></TR><TR><TD CLASS="quote">Displacement:
cubic centimeters X 0.061 = cubic inches (U.S.)
1599cc X 0.061 = 97.539 ci


CFM:
(RPM X Displacement) / 3456 = CFM
(8000 x 97.539 = 780312) / 3456 = 225.784722 CFM
</TD></TR></TABLE>

What happened to Ev?? It's needed at least for the stock (unboosted) cfm right?

 

Thats some really good info i that post or site I should say

 

Nice post. Lets not get too critical of him. He has helped me more than most people on here have. If you're going to hack his paper down at least contribute something of equal or greater value to the subject please.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by onemanlan &raquo;</TD></TR><TR><TD CLASS="quote">Nice post. Lets not get too critical of him. He has helped me more than most people on here have. If you're going to hack his paper down at least contribute something of equal or greater value to the subject please.</TD></TR></TABLE>

Who r you writing about?