the gt28rs obviously spools up earlier, also giving PSI earlier but the 2871r only takes a little longer so it cant be that.

The hks ssq is one of the only bov's ive had that activate on very low psi. On older bov's ive had Supersonic and megasonic Turbosmart bovs they dont even activate unless ur giving it a bit.

But with the Hks ssq it will activate even on idle and just revving slightly. But since the gt2871r it hasn't worked. I'm using a solo vac directly from the intake manifold, using Sard silicone 2mm internal vac lines which ive always used.

I do remember with my old 35/40 which i had on my first turbo setup.. that thing took until 5000+ rpm before bov would engage.