function wpse66815_search_query_string( $wp_query ) {
    if (!is_admin() && is_search()) {

        //print_r($search);

        global $wp_query,$wpdb;

        // get search term
        $search_term = $wp_query->query_vars['s'];

        //print_r($search_term);

        // specify string we'll use to replace
        $replace_var = 'TL';

        // find matches for that string
        preg_match_all("/{$replace_var}(?:[^0-9]*)(\d+)/i", $search_term, $out);

        // if there's no matches, return the normal search
        if ( empty($out[0]) )
            return $wp_query;

        // find/generate the search term with the replacement
        $modified_search_term = preg_replace(
             "/{$replace_var}(?:[^0-9]*)(\d+)/i"
            ,"{$replace_var}-$1"
            ,$search_term
        );


        // combine both the regular and modified search term
        $new_search[] = $search_term;
        $new_search[] = $modified_search_term;

        //print_r($new_search);

        // set $search equal to results
        $wp_query->query_vars['s'] = implode(' ',$new_search);

        //print_r($search);*/
    }
    return $wp_query;
}
add_filter('relevanssi_modify_wp_query', 'wpse66815_search_query_string');