Most of the engines from Audi and Mercedes in use today are DOHC engines with rocker arms.
From what I have read, the reason is a smaller lift on the cam lobe, thus a smaller max cam diameter.
This uses less power (lower inertia) to turn the cam.
And also, the rockers are always roller equiped, reducing friction.
This system on some Audi v8 5 valve engine uses only one cam lobe on the intake side, not 3, reducing cost and weight of the cam.
Is this something that will be in the game, eventually?
I think it has to do with keeping the game within a reasonable scope of realism. They could add all the hundreds of different ways auto manufacturers have overcome obstacles with engineering like this example from Audi, but it would add a lot of time and complexity to developing the game.
rocker arms are only used in OHV engines, they connect the push rod to the valve stem, on all OHC engines the camshaft pushes on the valve through one of two type of cam followers
le: never mind, lost in translation, in my native language they have 2 different names, i see that in English this is not the case