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#11
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So HOW HOT does that Pontiac Blow thru Carb get? Show you a bit more math today.
Example: the inlet temperature is 70 deg F, the suction pressure is -0.5 psig (a slight vacuum due to Inlet Plumbing), the discharge pressure is 19 psig, and the efficiency is 72%. What is the discharge temperature? Tin= 70 deg F + 460 = 530 deg R Pin= -0.5 psig + 14.7 = 14.2 psia Pout= 19 psig + 14.7 = 33.7 psia Pout/Pin = 33.7/14.2 = 2.373 (this is the pressure ratio) Tout = (530 + 530 x (-1+(2.3730) raised to the power of .263 ))) all of this divided by 0.72 = 717.8 deg R - 460 = 257.8 deg F So the theoretical outlet temperature is 257.8 deg F. I sure would like to have an intercooler to cool that hot air down before it goes into my engine. So assuming a 70% efficient inter-cooler 257 deg F – 70 deg F ambient temp = 187.886 deg F Temp rise from the turbocharger compressor So if you have a 70% efficient inter-cooler: 188 deg f times .70 = 131 degrees of temp removal So the discharger air out of the intercooler is 56 deg f hotter than ambient temp to the actual air Temp going into the engine is 126 degrees at 19 psi boost pressure This time I think the math will be easy to follow. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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