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Mr. Hypsi87, very good post, and your talking about something I was involved in at the University of Utah.
Some of the most heated arguements have been about turbo supercharging. The big myth you keep hearing is turbocharging is free HP cause it uses waisted heat and exhaust gas to make boost, whereas the centrifical, roots and screw type supercharger use the engine to drive them and consume large amounts of engine power to operate.
Lets establish two facts here. Fact one, the auto engine hates heat. Fact two, the auto engine hates exhaust backpressure.
Under controlled testing we installed different turbos on a engine with means of cooling the exhaust before it entered the turbo, in other words a cool exhaust. The difference between driving the turbo with hot exhaust and cooled exhaust was ZIP, nada.
The big difference was with cooler exhaust the turbos ran much cooler and the discharge air on the compressor was denser or more oxygen bearing air.
We went one step further and took a V8 and drove it with another engine making the engine a compressor. To that we installed a turbo to the exhaust side of this (engine) compressor and drove the turbo with nothing more than compressed air.
Everyone knows by installing a free flowing exhaust and headers you can gain 10-50HP on a stock engine. Now as you pointed out turbo's create back pressure. Your figures of 1.5-2 is alittle low, but close enough for the kinds girls I go with. This back pressure robs the engine of power. How much? depends on how much pressure you want to make. To compress air it takes power. I don't care what you use, to compress 10 lbs of air takes a given amount of power to make 10 lbs of compressed air.
Now a guy with this knowledge in Orem, Utah named Rick Squires (STS Turbo) and has developed a remote mounted turbo system, taking the turbo's to the next level. Being the turbo run cooler the discharge air is cooler (denser), cooler oil returning to the engine, much simpler mounting, and tests have proven more efficient than engine mounted turbos and less heat in the engine bay.
Old myths are nothing but old news, and those looking to get the most out of there cars don't need myths, but facts.
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