Search problems when using utf-8

Hello i have been working mostly with charset=iso-8859-1 today i encountered a server that has problems with that charset so i had to work with UTF-8, the search works fine with any characters that are not latin or spanish but if a word starts with Ñ or ñ i have to type the exact way its been inserted in the database why would this happen for example if i do APPLE or apple or Apple it will find any records with the word apple any way its writen, but if a word has an acent or for example Énfasis (spanish word) the search only works if i write it the exact way if i type in the search énfasis it will not be found, this never happened with iso-8859-1, but does with utf-8 and have not found a way to work this around any suggestions?

And i cant change the server its a cliente server wich has the Mod_security filter turned on, so if the get from the search shows any latin character it will not load the pages.

Thanks for any help