Want to make 20 minutes with truggy..

[malcster]

Currently running in my Losi 8T 2.0 4x cell 5000mah 30c lipos with Hobbywing 2000kv and getting about 12 minutes race time...gearing 45/15.
If I was to go to 5x cell 5800mah 30c with say a 1550 Tekin truggy motor would I reach 20 minutes run time?..also would I need to gear down from the 4x cell set up?..and would power be similar between the 2x setups?
Thanks.