and how it effects those plotted lines on the compressor maps (you posted the GT28R map), I will post the GT28RS map here:
 It is my understanding those lines were made simply using the engine volumetric flow or EVF on the page you listed. They do not take into account the following variables (listed in order of my understading of their importance). VE (or for simplicity say we will say how well the entire system flows).
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Temerature (ambient)
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pressure (ambient) - more dependent on alt. So, MY goal is to figure out how to try and take into account how those varibles effect those plotted lines (transform them to something useable to me). Hopefully Kenny or someone else who seems to better understands this will jump in on this. You state:
By increasing the volumetric efficiency of a motor, this increases the wheel rotational speed...
which will generate higher turbine / compressor temps which are evidenced by higher EGT's ...
Therefore, if you desire to keep the same EGT temps, you would need to lower the boost ... whenever the VE is increase, one should expect an increase in EGT at the same RPM points ... the real question is..where is the surge line ???
My understanding is the heat that is generated on the intake comes from two things.
1. physical heat generated by the turbo (spinning fast -friction), and heat soak from the VERY hot gasses powering the turbine side.
2. the act of compressing air (basic thermodynamics) Your statement about a higher VE causing higher EGTs I think doesn't take into account point 2. A better flowing engine (higher VE) will have LESS manifold pressure (boost) at a given power level vs. one with poorer flow. So, if the turbine/compressor wheels are spinning at the same speed on a car with 70% VE and one with 90% VE the one with 90% VE should be building less boost (less resistance to flow) but flowing the same amount of air and since that air is less compressed it should be cooler (lower EGTs). Now, the car with higher VE the turbine/compressor should spin up faster (it doesn't have to work as hard) but boost should build slower (since there is less resistance to flow). But, power should build quicker on the higher VE engine even though boost is lower because the intake charge is cooler with the same amount of air flowing. So, I think your statement about higher EGT due to higher intake temps on better flowing (higher VE engines) is flawed. Also, my understanding is the choke like (not the surge line) is what holds these turbos back on the top end of thier power output. I realize I could be misundstanding this or be confused and would love to have more input on this to better my understanding. Thanks in advance guys!
m a g l i t o
parts are FINALLY here - engine is going back together NOW
sig photo by me effects by ZXRider(SoCal)click here for latest build update post
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