Only certain types of air-meters work with BOV's, or else the ECU shits on itself when a few cubic feet of air dissappear, but theoretically, yes, any turbocharged car can 'blow off'.

.. and no, quite a few turbo'd cars actually come/came from the factory without a blow-off or bypass valve of any type. It just takes stress off of the turbines in the turbo.. but it's by no means necessary. I've owned 2 cars with over 200k miles on the factory-installed turbo's without BOV/BPV's, and they still run fine.

It'd have the same positive effects on a diesel truck as car? I mean, if he's hitting full boost everytime he accelerates, he might as well. No reason for him to blow his Holset. :sigh:

 

yeah thanks ill tell him .........