They were first called Race_1... Due to a patch with a massive overhaul of the physics engine, the old Race_1 setups were useless, and new ones were created and shipped with the new version... I leave you to figure out which patch that was...
Somewhere in the menus there is an option "AI use driver setup". Select it. Then, in the car screen, put the "race_s" setup on your car. Get out of the car screen, you should be at the pre-race screen now, where you can add AI cars. If there are any AI cars there already, delete them, then add them again. They now have your chosen setup. Then go back into the car screen and put the setup YOU want on your car. Back to the race screen and race!
Basically, they use the setup your car had when you added them. If you then change your setup they will still have the setup you had when you added them. Am I explaining this well enough?
But, WATCH OUT, this used to work in patch X, I have not conclusively tested if it still works like that in patch Y.
Keep in mind that downforce settings often have a impact on the "correct line". So it's often useful to get the downforce settings right before getting to familiar with a certain line.