All eclipsing nova-likes in the 2.8–4 h orbital period range belong to the group of SW Sex stars , and as such experience very high mass transfer rates .
Since the physical properties of a star should be independent of the inclination it is observed at , this suggests that all or at least a large fraction of the non- or weakly-magnetic cataclysmic variables in this period range are physically SW Sex stars .

We here present preliminary results of a large campaign to search for SW Sex characteristic features in the spectra of such stars .
We find that 14 out of the 18 observed non-eclipsing cataclysmic variables belong to the group of SW Sex stars the classification of the other four is uncertain from our data .
This confirms the domination of SW Sex stars in the period range of 2.8–4 h just above the period gap .
Since all long-period systems need to cross this range before entering the gap , the SW Sex phenomenon is likely to be an evolutionary stage in the life of a cataclysmic variable .