Cervan, if the turbo (either primary or secondary) is of the proper size and geometry, it extracts far more HP from the exhaust-heat than the pumping-work it adds to the piston-engine.

FI, thank you!! Yes, that was the point that got it all started.

You claimed that having the turbo doing zero pumping-work at cruise-power (20hp as I recall) was more efficient.

I pointed out that even at partial-output like 20hp, the piston-engine would run more efficiently if the turbo (using wasted heat-energy) was set up to do the work of overcoming intake-resistance; rather than using the pistons (whose work comes from burning additonal fuel).


JT, I think you summed it up well....

turbos need heat.....and obviously, turbos need a 'fan'...

__________________
WANT to BUY: 3.0L diesel engine.

My other diesel is a....

1962 Cat D9-19A, 2,000 cu-in TD
1961 Cat 966B, D333 TD, powershift
1985 Mack MS300P 8.8L TDI, intercooled, crane-truck
1991 F350 4x4 5spd 7.3 IDI NA
1988 Dodge D50 4x4 5spd 2.4 Mitsu TD
1961 Lister-Petter 14hp/6kw Marine Corp genset weekly charging 5400 lbs of forklift batt for the off-grid homestead.
1965 Perkins 4-108 Fire/water Pump
1960 Deutz 20hp/8kw genset