There's a good chance it's already there under the Themes section.
Themes is a great way to categorize certain things without adding more subforums. We try to offer a balance between having a nice selection of Galleries to choose from without cluttering the section up too much.
If there's no special thread for Automotive already there, feel free to be the first and start one!
There are several...there are three that pop into my mind off hand, one for general automotive shots, one for classic automotive shots and one for motercycles.