I have yet to find any information about this or if it has even been released yet. What engine is Brink built on exactly? Is it a custom engine or are the developers using pre-made engine?

If they information regarding the engine has yet to be released, then which engine do you think they are using?

It's using a very modified version of the id Tech 4 engine.

"Brink will feature Steamworks integration, including Valve Anti-Cheat. Its technology is id Tech 4 with a new rendering framework and improved support for multiple CPU cores." http://en.wikipedia.org/wiki/Brink_%28video_game%29 says.

I don't often use wikipedia as a valid source of information but, thanks for the info from both of you.