User, please tell us your jdev version!
A full use case will definitely help us understand what you are up to. Why not setting the inputText to autoSubmit?
The only other way would be to use java script and mimic the autoSubmit with a clientListener/serverListner which allows you to set the data without the simple autoSubmit=true on the inputText.
If you don't store it in the model layer you can use a pagedef variable (check Creating Variables and Attribute Bindings to Store Values Temporarily in the PageDef | JDev &amp; ADF Goodies) and use autosubmit on it,do your calculations on this pagedef variable and well finally you store it (may be on another even) in the model layer.
Or, as I said before use a client/server listener approach.