change page title using bbpress

I have buddypress installed, then I installed the bbpress forums that came with it. I like it however, I don’t want to call it “forums”. I wanted to call it “Group Topics”.
I can’t just go to the Pages section and modify it because it isn’t there.
How would I change the Page title “Forums” to something else?

I have tried this:

function modification($title){
    //make modification
    $title = str_replace("Forums","GroupPosts",$title);
    return $title;
}
add_filter('wp_title','modification');

it didn’t do anything. I also tried this from a different website:

add_filter('wp_title', 'set_page_title');

  $brand = array('name'=>'Brand Name');

  function set_page_title($orig_title) {
    global $brand;
    $title = 'Designer '.$brand['name'].' - '.get_bloginfo('name');
    //Here I can echo the result and see that it's actually triggered
    return $title;
  }

also didn’t do anything. I placed this code in a plug-in, then tried putting it in functions.php in the buddypress theme. Does anyone else have a suggestion? thanks for any help