8000 TPS in EOS


I have created a private network of 6 nodes in which 2 are block producing nodes and remaining 4 are non block producing nodes. I have changed block time from 0.5 sec to 1 sec. I have to perform 8000 TPS so I posted 2000 transactions on each non produicng node but only 1000 – 1200 transactions gets stored into block. Can anyone suggest how can I perform 8000 transations per second ?
I tried to perform transactions using javascript api as well as using cleos.