imben from ur description ures is jus an standard 'tong' chamber. the stoppers have been removed. quite useless job done. performance wise nt so obvious. a standard ori pipe can stil chase or even lead u depending on distance.
however Eyan's shorter chamber might be a aftermarket malaysian chamber pipe jus as ahm , pdk which points upwards.
another possibility is his standard 'tong' chamber section has been further cut short for better performance in short drag distance.