A couple days ago Chris asked how much a turbo could do if no wastegate was
used.  Of course the answer is highly dependent on many factors such as
ambient conditions, intercooling, mixture, etc, etc.  That said, I fired up
my spreadsheet and got this answer.  If you run 6500 RPM you should get
around 400 hp at 77 in-hg MAP and about 51 lb/min airflow (S.L., 100 deg
inlet temp).  If you go up to 8000 RPM the number is more like 500 hp.  I
guessed from the question that maybe the goal was to use the "excess" exhaust
for some other purpose.  In this case at about 240 hp, 6500 RPM, 46 in-hg MAP
there is about .16 lb/sec flowing through the wastegate with an exhaust
pressure of about 40 in-hg and an assumed EGT of 1650.  (Note that the
pressure ratio across the engine is highly positive at 46/40 indicating that
the BSFC would be noticably better than N.A.)

Are you gonna tell us what you have in mind??

Jeff Spitzer

 
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