i wonder what kind if fuel expenditure penalty comes from TWO turbos? nothing is free, or TNSTAAFL... i wonder what kind if fuel expenditure penalty comes from TWO turbos? nothing is free, or TNSTAAFL...Hard to say - the on-highway truck engine folks have worked on a similar idea since the 80s - to harvest more energy out of the exhaust. I’m not sure any have made it to production yet of course they’re shooting for 500,000 to 1,000,000 miles useful life.