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Old 11-20-2014, 12:12 PM   #26 (permalink)
Nigel_S
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Quote:
Originally Posted by kafer65 View Post
Nigel, thats some good information! Its got to be tough to calculate the speed of sound in a medium that is shedding heat and becoming more dense as it travels through the tube. On my Beetle header I loose so much heat before it gets to my turbo its hard to get it to build its full boost potential. It takes tens of seconds under acceleration to build the header heat for the turbo to convert to the last 4 lbs of boost. I have Jetcoated headers but I'm going to wrap them and put aluminum around that to keep oil off of the wrap. So many variables to contend with. You have the amount of fuel being consumed adding changing temps in the exhaust flow and the temps already soaked into the header and the speed of the airflow around the header pulling heat out too.
Well if you use the energy in the exhaust gasses to drive a turbo then the energy isn't available for extraction of the remaining exhaust gasses so the piston has to do the work instead using extra fuel. That's why a turbo engine of the same capacity as a NASP has lower fuel efficiency. It means that the design of the headers is not so important since all you are really interested in is driving the turbo sufficiently to give the boost while causing as little backpressure and thus extra work for the pistons as possible. Sounds like yours is a semi-turbo - trying to do both!
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