Project Cars

I won this by accident while trying for another achievement. Setup a 5 lap race in solo mode with one opponent, and no qualifying or practise sessions (with a random grid order, you have a 50% chance of 'qualifying' first). After getting to the lead at the end of the first lap, you can let the AI finish the race for you by selecting sim in the pause menu.

I was trying for the '3x laps within 0.1 seconds' achievement, but it did not pop for me first go. It might pop for you if you're lucky though.

In addition to "A Volvo Driver" great solution,
I set the starting grid to Player starting in first, then drove the race myself in a 125cc kart at Oschersleben C Circuit.
My ai driver, when I chose simulation after 1 lap, would always lose to the other ai kart in a last second pass just before the finish line on the final lap.
Tire wear set to "Real", Full Damage on, Mechanical Failures on.

This is my solution to Requesting Flyby (Enter and exit the pit lane without losing a position (cannot be in last place) which also covers getting this achievement.

Basically set up a race weekend that meets the noted criteria with 1 other opponent. I personally used the track Imola but choosing a track that is familiar to you would be beneficial.

Next I set the opponent skill to beginner, this guarantees that you will win (I hope)

Lastly choice of car, I personally used the Caterham Prototype 2 as it was a fun car to use, again a car you are used to would be beneficial.

Start the race, I waited till around lap 3, so the opponent was quite some distance behind me, did my pit stop. It allows you to decide what happens when you pit in and details the time it will take. I took on the minimal amount of fuel as I could and back on the track before the opponent was anywhere near me.

Achievement pops as you exit the pit lane, finish your remaining laps to obtain the Gladiator achievement also.

This is incredible easy.

-Go into your options and set Damage to "Full Damage", Mechanical Failures to "Yes" and Tire Wear to "Real"
-Go to Quick Race and choose the 250cc Kart and set the track on Oschersleben C Circuit.
-Set your laps to "5", number of opponents to "1" , grid position to "first" (this really won't matter) and opponent skill to "0"

Start the race and you should have no problem beating the AI with beginner difficulty. I lapped my guy on the 4th lap.

Achievement will pop after the race is over.