While pyro instancing works fine for most of the situations, the tracking object feature doesn't work properly with track by object turned on in the Gas resize fluid dynamic node.

I dig into the Gas resize fluid dynamic dop node, but couldn't find a solution to make it work. What i want is that each cluster container will resize according to each track object of its cluster.

Hope someone can help.

Did you check Rob's file here:
http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=26547&highlight=clustering [sidefx.com]

and Dobril's here:
http://forums.odforce.net/topic/17266-smoke-trail-on-path/ [forums.odforce.net]

If you have any problem let me know I have my version too.