On the official Peugeot Sport you can see a minor puff of smoke accelerating out of a corner:
http://www.youtube.com/watch?v=fIf8BpUx7qo#t=2m11s
In the Sebring test video the R18 produces lots of smoke on startup in the pits:
http://www.youtube.com/watch?v=S9e15hs_T0k#t=0m49s
but also on the track:
http://www.youtube.com/watch?v=S9e15hs_T0k#t=1m22s