And yes on every engine I have tested it on the small 7 mm venturi had the same effect with all engines ending up making very close power to each other. Which shows me the 7 mm venturi is a major limiting factor ...5 port, 7 port and 9 port doesn''t matter nearly as much, in fact the highest powered engine I have tested is a 5 port anyways..... As long as everyone is running a 7 mm venturi on the same nitro % everyone is going to be in the same boat...running their engines well below its full potential.........