Upvote to x The Rook x for the solution above, however that method he did was taking about an average of 3 1/2 mins and about 3 times around the track due to ppl knocking trophies off leader etc. for each racer/constructor. A much faster/easier was is select
Belgium (custom)
Race
Laps 1
Power-Up Balance: simple
Damage: none
Modifiers: Project Orion (constant boost)
1,000cc
The race will last 1 lap and with the constant boost, even at 1,000 cc, it is quick and easy to control car. Lap will last about 1 min give or take a few seconds even at 2nd place. Much faster to get through this achievement.
Also note, no, you do NOT have to come in 1st place on any/all of the races. Many I came in even 9th and 10th just cuz I suck haha