28000 miles oil changed
Blackstone even recommend extending it up to 35000 miles. Oil is AMSOIL ASM 0w-20 I think this is their premium oil.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1317767&fpart=1
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1317767&fpart=1