When changing your oil bath filter to a standard air filter is there a increase in power ?
Not likely unless the filter medium in the oil bath type is clogged by the dust/dirt of ages past. Even then the only benefit the dry filter will provide is increased air flow because it is clean. A dirty filter of any type costs power. On the upside, the dry filters are must more efficient, especially in terms of removing fine dust, than the oil bath type. Just be sure to install the filter with the biggest exposed area that you can make work.