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Old 04-29-08, 04:32 PM   #32
Dougal
IH8MUD Lifer
 
Join Date: Jun 2007
Location: Being stalked by 2 hillbillies
Posts: 1,425
Quote:
Originally Posted by NStimac View Post
Dougal what about the hot @$$ turbo your passing all this air through. How hot do you think it is 400-200 F. Never minding the fact that a turbo isn't 100% efficient (like your math implies). Idea gas laws are ideal. What's happening under the hood isn't. 10psi + you will see a gain from an ic. Below that you might see a drop in EGTs but preformance wise you might not be gaining anything.
The turbo compressor doesn't pick up any significant heat from the exhaust. Mainly because the bearing core is cooled by engine oil and is quite a long path for heat to conduct along.

My maths is based on a 70% efficient turbo compressor, I have temperature measurements to back them up and since your average turbo compressor map plots from 65% to 74% it's a good figure to use.
At 15psi with the T25 I measure 115C
Calculated at 70% effiicency I get 113C

Using an IHI turbo with a damaged compressor wheel (dust erosion) 15psi resulted in over 140 deg C, the equivalent of 55% efficiency.


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