I need Turbo Gurus, compressor map/surge question

I have to replace the cylinder head on my GLH, which means it is a good time to revisit the turbo I've got in there.

The current turbo is a T04B V trim compressor wheel, T04B compressor housing, T3 a/r .63 turbine housing, stage III turbine wheel with a ATP ultimate wastegate.
It will surge above 27psi. Below is the compressor map I calculated using data from MS log and Dyno graph.

I potted the same graph on a T04E 50 trim, and it looks like I will stay out of surge but I am left with only a little bit of head room to make more power.

The new cylinder head will flow 10% or so more CFM, can I assume I will be less likely to surge if I stay with the V trim turbo?

I wanna see 400whp with my setup and a wider power band is always better.

T04B V, blue lines is 367whp settings, pink lines is 248whp setting
http://thelostartof.net/tryingbe/dod...tion/btrim.jpg

T04E 50 trim, blue lines is 367whp settings, pink lines is 248whp setting
http://thelostartof.net/tryingbe/dod...ion/50trim.jpg

Dyno, red lines is 367whp settings, blue lines is 248whp setting
http://thelostartof.net/tryingbe/dod.../dynosurge.jpg

MS on the 367whp
http://thelostartof.net/tryingbe/dod...tion/surge.jpg

Scale of the graphs are misleading. Blue dots at the end are operating at 70% efficiency on the t04b vs 74% with the T04E 50trim. Also the To4E reads to only 65% efficiency vs. 55% for the B. I'd say based on your plots the T04E would be a step up. I also looked at the map of the original GT30R (not the new fancy GTX's) and all your points sit in the sweet spot of that map.

I've come to the conclusion that I am doing this for educational purpose, not necessary to win a race or be a dyno queen so I want to change one thing at time and see how it effect the system.

So, since I'm changing the ported 782 head to a ported G head, I'm going to leave the turbo the same and dyno it and see where I am at.

Then I'll make a discussion if I want to go 50 trim or a expensive GT3076R

Factually surging or surging on your graph?

What are you using, Frank's Excell or what? I question the lines I am seeing.

If you move more air, you move to the right on the graph. Ported heads should flow more at the same boost if your setup supports that improvement. Your other way of avoiding surge is slowing spool with a Stage V wheel or taking some material out of the "nozzle" on your housing to slow velocity (which would decrease backpressure and potential power gain). I have modified housings before. It works if you are able to get access to the right spots.

Electronically you could just slow boost rise.

The V wheel certainly looks better. 50 trim overspeeding and off the chart if you up boost.

Quote:

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Originally Posted by Ondonti

Factually surging or surging on your graph?

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Actual surge, see dyno graph and MS log.

Quote:

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Originally Posted by Ondonti

What are you using, Frank's Excell or what? I question the lines I am seeing.

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http://www.turbo-mopar.com/forums/sh...=1#post1079375

Quote:

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Originally Posted by Ondonti

If you move more air, you move to the right on the graph. Ported heads should flow more at the same boost if your setup supports that improvement. Your other way of avoiding surge is slowing spool with a Stage V wheel or taking some material out of the "nozzle" on your housing to slow velocity (which would decrease backpressure and potential power gain). I have modified housings before. It works if you are able to get access to the right spots.

Electronically you could just slow boost rise.

The V wheel certainly looks better. 50 trim overspeeding and off the chart if you up boost.

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I thought as much and going to stay with the V trim for now.

I never had a chart look like those. Should flat line after reaching target boost. No legit Excell at my house to run the program anymore and he wouldn't open it up to add more maps.

I like the Excell better than the online calculator that existed.

Quote:

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Originally Posted by Ondonti

No legit Excell at my house....

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I recommend LibreOffice it works well and open source(aka "Free as in beer") https://www.libreoffice.org/

here's another excel alternative https://www.openoffice.org/welcome/credits.html

Quote:

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Originally Posted by wowzer

here's another excel alternative https://www.openoffice.org/welcome/credits.html

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LibreOffice is forked from Openoffice which was originally StarOffice. I used all three when they
LibreOffice is currently more active than the other variants and included in many versions of Linux. Yes, I am a Linux guy since the mid 90's.