Here are the settings I have used rendering the Audi car in Vray.
This first image is for setting up the IBL using vrays dome light, along with rectangle lights. The global illumination settings are similar to that of mental ray and it takes multiple small increases of the subdivisions to increase lighting quality, reduce noise, and reduce render times.
The next image is for creating render passes. It is much simpler in vray than it is in mental ray and only requires a few clicks. You can select the desired render passes from the left and add them to the right, this then apply each pass to the multi channel EXR file. Some passes such as Fresnel and ambient occlusion are not in the default render passes so you to create a custom pass using the extra tex pass. This then allows you to apply a shader to any pass to create the pass you want. In this example I am showing how to apply the ambient occlusion pass.
Here are the render passes, in order they are, beauty, reflection, refraction, Fresnel, shadow, specular and ambient occlusion.
In vray to smooth a mesh for rendering it needs to be subdivided at the render stage not by pressing 3 or apple the ‘smooth mesh’ tool. This gives better results compared to maya’s subdivision method.