I'm going to guess that you're hitting the max injector duty cycle. The stock injectors don't really have a lot of flow left over the stock power output. If I remember, 440cc injectors max out at less than 300 HP worth of flow on most Honda engines, so think about where that would put you with the stock 240ccs....

The only way you would have a boost cut is if you have the ECU chipped and have been tuned using one of the software packages that adds a boost cut (like Hondata). Otherwise, if you are using the stock ECU and the stock MAP sensor, it will freak out (and throw an error code) when you hit around 11 PSI of boost pressure.