" From: Tom Jennings <tomj@xxxxxxx> " " Sandwich Maker wrote: " " > i'd guess about the point the exhaust valve begins to have meaningful " > opening... there's still plenty of heat and pressure in the exhaust, " > or turbos wouldn't work. " " It's pure waste, 100% wasted energy. Down the toilet energy. of course. but in a reciprocating engine you can't capture all the expansion energy easily if at all. even if you didn't open the exhaust until bdc. i've heard of compound engines where the smaller combustion cylinder exhausted into a larger cylinder for further expansion, but if they really worked all that well we'd all have heard a lot about them. " If you were to build two motors for exactly 100hp output at WOT, one " normally aspirated and one turboed all dialed in, the turbo one will use " a less total fuel, and have a lower exhaust temperature. It will also be " a smaller displacement. The same amount of ENERGY will be produced, and " that came from the fuel -- the rest of the fuel energy was pi**ed out " the tailpipe. that's why turbos are sprouting up all over the auto world now, and why you'll be hard put to find a diesel without one. " All turbos will have lower exhaust temperature. Heat == energy, energy " == heat. The waste heat expands gases and pushes the turbine, that very " act lowers the temperature. That's just basic physics, nothing car specific. so why haven't we seen more turbos before? i'd guess economics. turbos are precision high-speed devices; first it took industrial infrastructure to build volume and drive costs down, then it took rising fuel costs... ________________________________________________________________________ Andrew Hay the genius nature internet rambler is to see what all have seen adh@xxxxxxxxxxxxxxxxx and think what none thought _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list