great help @ http://mansurovs.com/tech/converting-vbulletin-to-utf-8
these are the exact commands that worked for me
mysqldump -u VB_forum_DB --default-character-set=latin1 --opt --ignore-table=VB_forum_DB.customavatar --ignore-table=VB_forum_DB.customprofilepic --ignore-table=VB_forum_DB.picture --ignore-table=VB_forum_DB.socialgroupicon --ignore-table=VB_forum_DB.socialgrouppicture VB_forum_DB > VB_forum_DB.sql
mysqldump -u VB_forum_DB --opt VB_forum_DB customavatar customprofilepic picture sigpic socialgroupicon socialgrouppicture > VB_forum_DB_images.sql
iconv -c -f WINDOWS-1256 -t UTF8 VB_forum_DB.sql -o VB_forum_DB_utf8.sql
mysql -u VB_forum_DB VB_forum_DB < VB_forum_DB_utf8.sql
mysql -u VB_forum_DB VB_forum_DB < VB_forum_DB_images.sql
