Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

True, but only a very few pounds less pressure resistance to your exhaust pressure, so negligible to a high pressure boiler engine combo, but perhaps more significant to our models that operate at relatively low pressures?!?!

Now if you are operating with a condenser that actually manages to pull a vacuum on your steam exhaust, then you are definitely gaining a bit more power, if you have your system balanced to be able to make use of that pressure differential.