went from vta bov back to oem metal diverter valve and experiencing some knock counts. haven't logged yet but when cruising if I apply part throttle lightly, cel begins to flash fast (more than 6 counts of knock) untill I lift off.
and also when doing low rpm wot pulls it flashes during spool up but with slow flashes this time. before had zero issues with vta bov.
changing bov needs retune ? or there's some other issue

 

You must be hitting higher loads than before, your load curve had probably shifted. Max boost is probably a bit higher too.

 

why that ? is it common with dv's ?

 

A while ago, I removed my HKS BOV & installed the stock metal, boost went up by 1.5psi. The stock BOV must have a stiffer spring. If you invert or cancel the BOV, boost will even go higher.