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Ok well I have been doing some homework on reading compressor maps and picking the right turbo and I decided to test it out. I am still quite new at doing this some some constructive criticism would be appreciated.

here is a compressor map for a gt2876R, to find CFM I used 2.261 L/ 137.97 ci for displacement, an efficiency of 88% (not sure on this one, I could be way off) I just figured my intake and exhaust would increase the efficiency a little, and max boost of 8 and 15 psi. Don't worry if the pressure ratio looks a little high... I live in Denver lol

 

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what are you looking for? looks like a good turbo, but it's been known that it's a good turbo for 2.0-2.5 engines for a long time.

i ask this every couple years and never remember the answer, but running 8psi in Denver is putting a load of 22psi on the turbo isn't it? as a turbo's wastegate is absolute pressure (unless it's being controlled electronically) it doesn't care that it's starting at -14.7 rather than 0psi.

if that were the case even, looking at the 2.5 line you'd fall within the 72% or better efficiency area from 3500 to redline....which is pretty damn good. in which case you really wouldn't worry about blowing hot air until you start playing with 12-15psi.

...i didn't bother looking, this is just the way what always makes sense in my head.
 

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I was just seeing if I was doing the map right. I had read a somewhere that it is a good turbo for our engine which is why I chose this one. The absolute uncorrected (not the one the weather man shows you) pressure in Denver is usually in the low 12's so absolute pressure on the turbo would actually be more like 20.

Can I ask if my volumetric efficiency number is anywhere close to being realistic? That was the one thing I was really unsure of.
 

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http://cid-5e8dd8a02f0298a1.office.live.com/embedicon.aspx/.Public/Flow Test.xlsx

here's a spreadsheet i made years ago when looking at turbos. i broke it down into lb/min, cubic meters and cubic feet, as that was the various forms i saw used on compressor maps. i input displacement for our engine, the V6 as well as the protege's 2.0 as well, just need to change the upper left value and the rest is carried over.

i use a general 85% VE as you can see as well
 
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