| to the fact that we have two parallel operating turbochargers, of which I haven't seen put into use on an inline-6. The parallel operating turbo setup creates the potential for imbalance to affect the engine's seperate banks of cylinders. As an example: (on a Z32) JWT dual POP, Greddy FMIC:
The MAS is only metering the intake air to the driver's turbo. The ECU is going to deliver a quantity of fuel according to the information given by the MAS. If the passenger turbo is flowing more air than the driver's side, it will move that air through the FMIC and into the passenger bank of cylinders, but because it is flowing more air than the driver's side is, it will run leaner than the driver's side. This is the #1 reason in my book to avoid cross-flowing FMIC setups. Even when you aren't using a crossflowing FMIC setup, there is still room for variation. Any imbalance is ultimately dependent on the wastegate actuator tension balance between the two sides. This kind of imbalance is only going to be found on a parallel twin-turbocharged kind of setup. Any inbalance of A/F in an I6 setup would be more along the lines of injector variations, which would account for smaller deviations than those I am addressing in the parallel twin-turbo setup on a V6 engine. AFAIK, no one with an I6 uses twin-turbos where each turbo is only feeding 3 cylinders. The Supra's OEM twinturbo setup is a sequential setup, of which wont have this same kind of problem.
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