Does VAFC II or I void warranty for car? Thanks

 

if it's the factory warranty, then yes, if it causes a failure of some part. if you have something break, i suggest you remove the VAFC before taking it into the dealership to be safe.

if it's an aftermarket (hondacare) warranty or extended service contract, then yes, regardless of what breaks, since any aftermarket parts are enough to void warranties such as those.

 

Considering that if you don't know what you're doing then you can set it to pop your motor, sure it should void your warranty.