[jakobnev]

(I excluded heating/cooling of gas due to expansion/compression for simplify)

Well to create 1cm³ of vacuum when working against 1bar of pressure requires about 98mJ of energy.

A 2litre 4 stroke spinning at 600rpm with full manifold vacuum needs 1000w for the pumping.



At 250mBar it takes about 40mJ/cm³.

If you were say, running a 2dm³ engine at 2500rpm and 250mBar manifold pressure a perfect TB-motor could generate 1300w of power. (and 2700w if the gas was heated to twice the absolute temperature by engine exhausts.)