there are theories that say bellmouths are no good and only increase turbulence and these same people support the chamfered edge runners as they come from factory. how do the bellmouths fix the problem ?
I would say that bellmouths work in pleniums
I have done tests there
Plenium Runner lengths and Bellmouths must be worked out varying on the type of engine
There are engine Simulation programs to work Runner Lengths ETC
As for the standard Manifold no 6 problem like stated Changed the no 6 % in the ECU
If people are serious and wish to get rid of these in the right method they will need to change pleniums
The problem in the Cylinder is lack of air flowing so a larger plenium with give more air flow
As for the EGTs in each cylinder will be an interesting test
might have to try this next to check AFRS in each cylinder