Are the throttle body inlets the same size on the 4b11 and 12?

 

yes

 

Not only is the diameter the same , the TB itself is 100% identical between the 4b11 and 4b12
I'm yet to lay my hands on a 4b10 but I'm willing to place bets it's the same across all 3

 

4B10,11,12 all have the exact same 57mm TB and exact same intake manifold. There is a variation in the intake manifold in that some models like Outlander or Delica have resonators built in to the manifold whereas the Lancers do not. What is different is how far the ROM will allow the throttle to open and in what gear.
The 57mm throttle poses no restriction to airflow on a 4B12 until about 4000rpm as measured by logging MAP and only 50% throttle is required to go full airflow at 2000rpm. I have not tested this on a 4B10 or 11 after the throttle settings are adjusted to allow 100% opening. Logic would say a 4B11 being 83% of the 4B12 capacity, would rev to 4800rpm before the throttle becomes a restriction and the 4B10, 5333rpm but both the 4B10 and 11 are crippled by the miserable intake cam lift and duration which is the major source of restriction - a larger throttle is absolutely pointless on these engines while the stock intake cam is present.

 

@jajk So if you have an Outlander you should swap intakes with a lancer? I have a 4J11 and looking for some info to make some more HP say 15-25HP now and 100HP when I turbo charge it...

 

ASX_Billy The 4J11 engine is a completely different beast to a 4B1x engine and nothing will interchange. They share the original 4B1x block and crank but that's all. These engines are a very, very bad candidate for performance tuning. They are designed to be cheap and nasty, euro 5/6 compliant and perfect for Hybrids.