My FE/Performance Project

[pgfpro]

Originally Posted by shatto

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?

On the P-38 and its turbo placement I have no idea why they did what they did. I do hold that plane close to my heart because it was my Dad's favorite plane that he worked on in the Air Force during WWII as a airplane mechanic. In fact I have a knife that he made from a P-38 that was grounded from major Combat fighting. He said he used the propeller, propeller cone and the cockpit glass to make it. Its Cool As Hell!!!

The turbo companies do want the turbo close to the exhaust valve to utilize the heat. Today's turbo's have made major advancements just in the last 10 years. Turbo lag has become a thing of the past with the correct sizing.
Turbo Technology has come a long way.