I don't see your build as that rare regarding tuning. A twin screw blower makes less heat, boost comes on earlier and has a flatter boost curve than a turbo or centrifugal blower. So you want it to go into open loop fuel earlier than a centrifugal, less heat is not a problem nor is the flatter boost curve. A centrifugal blower is not any harder to tune, just a bit different and yes My first tune and blower was a cheapy Powerdyne.
The MAF wouldn't be the problem as your tuner should have the MAF curve input for your MAF. I have not heard of a need to flow test a MAF, they are precise instruments, and come with a MAF curve or table which is what a tuner would put into the MAF Curve in the tune.
The injectors should also have been input properly, but the fact that the pressure is higher makes for additional calculations to get it close. Then datalogging to fine tune with the MAF curve if necessary. It took me some time with my blown 4.0 and now 5.0
I am using all the injector parameters except for increasing the injector slopes for the higher fuel pressure. I am running what would be considered 43lbs injectors at the typical pressure, at 65psi I have my injectors set in the tune as low slope at 55 and high slope at 50. The EEC compensates for rich conditions with injectors at idle and low RPM by using an injector break point, below a certain threshold the EEC switches to low slope and fires as a 55lb injector which means a shorter pulse width and less fuel. That cures typical rich conditions down low. The rest of the time it is using the high slope. The high slope is supposed to be the injector size but we got more fuel pressure and more fuel.
I think the stock 19lb injector are in the tune for the 4.0 at around 24lbs...................................for the higher fuel pressure.
I have heard nothing but good about your tuner and wonder, sometimes new parts don't work right, and I hope that is not the case.
