Just to clarify this, anything that can give your lap an unfair advantage will dirty your lap, which can include cheating by running off at the end of a previous lap and drafting. More relevant to this quoted point, it’s not just drafting that speeds you up but also being drafted can make you slightly faster.
Yes, but this is not very realistic! The use of slipstreams are ESSENTIAL in real races and FM 5 wants to be a sim! In reality no driver gets a dirty lap for using a slipstream but in FM 5 you also get a dirty lap when a opponent uses your sllipstream… WTF?!
You get a dirty lap due to the fact that in rivals/hotlapping it is one car running alone on the track. Since your lap times that come from races that include other cars also post to the Rivals leaderboard, drafting is counted dirty as to not gain an advantage from it.
Also you could have a multiclass race and get a X class car to push your c class car thru the start line giving you a major speed boost. It was done before they added the dirty draft in previous forzas.
You can still draft and win races, it just wont count towards rivals.
Slipstream also gives the leading car an advantage by making the air behind the car more turbulent so it works for both parties involved
Going slightly off topic but Moto GP never had drafting making the laps dirty and as such me and a friend were able to set some rediclous lap times (some nearly 2.5 secs quicker than a non drafted lap)