Yes, you're doing it wrong
An Xbox game does not have any VOB files on it, so if you're seeing them you're doing something wrong. An Xbox game is also rarely larger than 4GB (some games excepted like Halo 2) so if you're getting 14GB files then you're definitely doing something wrong.
Here is how I do it with my Xbox. My Xbox has been flashed with a new BIOS allowing me to set-up an FTP connection with it. I have loaded the Evolution-X dashboard which allows me to disable automatic game boots. If I want to backup one of my original Xbox games I turn on my Xbox and then fire up the FlashFXP on my PC. I then connect to my Xbox so I can browse its contents. I now insert the Xbox game in my Xbox and wait a couple of seconds. I can then, on my PC, browse the disc's contents via FlashFXP and transfer the files from my Xbox to my computer.
If youâ€™ve never done this before it sounds difficult but believe me, once you can setup a proper connection with your Xbox then itâ€™s very easy to do. For more info on how to setup an FTP connection you can read these tutorials over at Xbox-Scene.com. Personally Iâ€™ve used this method to setup an FTP conntection: Networking xbox to pc using 2 network cards.