I'll have to ask on the specific brand (I was thinking impco) but Kaseys lbz is using a vacuum regulator. It introduces CNG into the turbo inlet, so there is lag to an extent. Marc Deluca does have a controller setup to use a higher pressure regulator and injects it into the manifold, of course this setup is more expensive, and you change the throttle table to only inject 1-5mm3 up to 50% throttle input and the CNG controller flows more with pedal input. Throttle table ramps up smooth from 50-100% so it drives normal with no CNG.
How do you have yours set up?