A diesel blow off valve is definitely only for diesel turbos. Normal diesels, because of the way they are designed, have no need to have a blow off valve. As it is direct injected, a normal diesel wouldn’t have anywhere to use a blow off valve. It has no intake of air or throttle plate. Instead the fuel and air are combined in the combustion chamber of the vehicle. The excess goes direct to the manifold, where it is utilized by the normal running of the vehicle. Some alterations have taken place to meet emission standards over the last few years, and the throttle plate has been introduced in some models, but they still have no need of a blow off valve.
For more info, see Installing an HKS SSQV Blow Off Valve