Using custom variables

Hi my navbar_hook use this code so I can use the $z on my forum navbar, but this $z is not appearing on arcade.

Can Anyone Help me?

if ($vbulletin->userinfo["downloaded"]) 
        { 
          $ratio = $vbulletin->userinfo["uploaded"] / $vbulletin->userinfo["downloaded"]; 
          if ($ratio < 0.1) 
            $z = "<font color=#ff0000>" . number_format($ratio, 2) . "</font>"; 
          else if ($ratio < 0.2) 
            $z = "<font color=#ee0000>" . number_format($ratio, 2) . "</font>"; 
          else if ($ratio < 0.3) 
            $z = "<font color=#dd0000>" . number_format($ratio, 2) . "</font>"; 
          else if ($ratio < 0.4) 
            $z = "<font color=#cc0000>" . number_format($ratio, 2) . "</font>"; 
          else if ($ratio < 0.5) 
            $z = "<font color=#bb0000>" . number_format($ratio, 2) . "</font>"; 
          else if ($ratio < 0.6) 
            $z = "<font color=#aa0000>" . number_format($ratio, 2) . "</font>"; 
          else if ($ratio < 0.7) 
            $z = "<font color=#990000>" . number_format($ratio, 2) . "</font>"; 
          else if ($ratio < 0.8) 
            $z = "<font color=#880000>" . number_format($ratio, 2) . "</font>"; 
          else if ($ratio < 0.9) 
            $z = "<font color=#770000>" . number_format($ratio, 2) . "</font>"; 
          else if ($ratio < 1) 
            $z = "<font color=#660000>" . number_format($ratio, 2) . "</font>"; 
          else 
$z = "<font color=#008800>" . number_format($ratio, 2) . "</font>"; 
        } 
        else 
        { 
          if ($vbulletin->userinfo["uploaded"]) 
            $z = "Inf."; 
          else 
            $z = "---"; 
        }