Its not figured out fully by what I gather and Ive also not been called upon to dyno tune one(never owned one either). This doesnt mean they dont work and may work well, just have not seen it yet personally. If someone calls me up to meet at a dyno to tune a PCV and I have my laptop on one and see for myself then I may or may not change my mind lol. Ive tuned tons of PCIIIs and know they work. The PCV still needs a base map to work off of so yes, IMHO they need dyno tuning as well.