[jpnovak]

There are some definite tricks to tuning ITBs. Though they are not that much different than tuning any engine (common plenum) once you understand the principles of what you are doing.

I will add that scaling of your MAP (load) bins is very important to ITB tuning. They will not be evenly spaced. You should notice a steep upturn in your fueling delivery as the efficiency of the ITB flow takes over from throttle opening. This is as the manifold pressure starts to approach atmospheric. Typically this is right near the 90kPa pressure isobar. Funny how that can be a default setting on the ITB_Mode switchover curve... This is where you need more resolution to accurately control fuel over the rapidly changing pressure and amount of fuel required to control it.

You also need to make sure the load bins (MAP) cover the dynamic range of your engine. Don't put a 10kPa bin on there if you only pull 35kPa under decel. And yes, you might see more than 100kPa if your engine is efficient enough and air density is high enough.

I will also say that if you want to determine your ITBMode switchover points - do not wait until you have started the steep upslope on the fuel curve. You will have some abrupt transitions as the ECU switches tables.

The same can be said for the RPM bins and even more so at boost onset on a turbo car.

I have baseline distributions for different intakes. Then tune to a very well running car. Then adjust and scale the tables to match the shape of the fuel curve, and finally fine-tune with proper scaling.

Do you have a knock sensor? If so, it is easier to play with how much timing you can add into the engine.