My FE/Performance Project

[shatto]

Originally Posted by pgfpro

I'm sorry but I'm not understanding your question???

Turbo manufacturers will tell you that there are two things that turn the turbine wheel. Heat and Exhaust flow(temperature and pressure)

I think you agree with the exhaust flow part? On the heat side this is why they use advance materials to make the turbine wheel and when you use header wrap you actually help the turbo spool.

On rear mount systems that I have built and use from a major manufacturer you loose a lot of this energy and usually have to up the size of the turbo hot-side itself because a loss of the turbo's turbine efficiency.

Interesting is about heat and gas flow. I once read a dissertation on high performance exhaust systems and the end result was that too big wasn't good because of heat loss. Seems the hotter the exhaust at the tip, the better for scavenging. Something like that.
On the other hand, if keeping the heat in was so important one would think Lockheed would have placed the turbochargers on the engines, not 10 feet away on the booms of the P-38. Or used two stage mechanical superchargers like the other inline engines used..

Is it not true that the reason we need exotic high temperature materials for the impeller because they want the turbo as close to the exhaust valves as possible......to overcome....."turbo-lag?" Is that lag not the reason racers who need instant power do not use turbochargers but default to the good old Roots, in drag racers?