Continue playing to unlock this secret achievement. (Secret)
This is a very easy achievement, I got it in my first try.
You have to drive 333 km/h wich is 207 Mph (thanks to Dibbs93).
Go to Free Practice.
Car: Mclaren F1 (DLC) or Mclaren P1 (thanks to NMANOZ)
Condition track: Clear
When you drive out of the pit, just turn around. Take the corner to the left and then drive through the chicane on to the long straight. At the end of the long straight the achievement will unlock.