F1 2013

Having just gotten this achievement, here is my boosting guide.

Get a 2nd player to help you out, however they don't need to race.

1. Select Multiplayer from the menu
2. Xbox Live
3. Custom Race
4. Create Session
5. Adjust the Host Options to whatever you want.

Main ones are :-
Settings > Race Distance > 3 laps
Weather > Clear
Track > Classic Tracks > Brands Hatch

Simulaton > Car Damage > Off
Collisions > Off

Session Settings > Max Players > 2
Privacy > Invite Only

Then SAVE Host Settings, so you don't have to do them everytime.
Create Session

Invite other player to the session, then Ready

Once in the car > Press 2 times (unless your in a 1980s car).
When the race starts PLAYER 2 do not move. You'll be disqualified (after around 1 min) and the race will reduce to 1 lap.

PLAYER 1 takes the win, and the race ends. I know its not about race wins, however you only need to do 1 lap at a time this way (around 1m 20 secs) and not the 3 laps you would have to do if you both drove.

So with this method you'll play 100 - 1 lap races, rather than 50 - 3 lap races.

To check it counts go back to the Multiplayer Menu and select Leaderboards and Find Me. This tells you how many Wins / Races you've done.

If Player 2 quits it does not count.

I got this at 25 races.

Happy Racing

It's worth to add that Split Screen races WON'T COUNT for the achievement while Co-op races will so you can do large portion of achievement while going for your Driver & Constructor co-op title.
Just remember what Giermol wrote in '50 races' guide, DNF's and Disq. doesn't count, you have to finish race.

This did not pop for me until 33 completed on-line races.

I don't think Codemasters can count so just keep pounding in the miles until it comes your way.