Due to the difficulty in producing (and using!) cheat codes for mobile games, cheats for Rally 3D are very rare. Try typing in 'GOODBYECARS' as this unlocks all the cars available in the game.
The website chip-tuning-cables.com used to have some cheat codes for this game, but these appear to have been removed.
There are tips to help you complete the tracks faster available on the Nokia Support Discussions Forum, perhaps if you posted a request for help there, someone may come forward with cheat codes.
For other blurtit responses to this question, check out How can I unlock the cars of rally 3d in nokia 2730 by using cheat code? or try
Can U Give Me The Cheat Code Of Rally 3d Game Of Nokia 5130 Xpressmusic? or maybe What Are Some Cheat Codes For Nokia Games?
Let's hope you do better than these rally drivers:
