The amount of points you receive depends on many factors, such as the number of races you've completed with that car, who you've raced against, and your overall win/loss ratio. For example, if you beat someone with a high score, you'll get more points than if you beat someone with a low score.

Your rank also depends on the total number of races you complete. The more you race, the closer your rating should be to 'real', as it is adjusted for each win and loss. For example, if you win your first 10 races, you won't be at the top of the ladder because you haven't raced enough. If you start to lose and then lose 10 more races, so that you have a 50% win rate, you'll get about the same amount of points as if you lost the first 10 races and then won 10 races, so in the end it doesn't matter how or in what order you win or lose those races.