Search results depending on search word length?

New to solr so maybe it's studip question, but here we go:

I've got a long title name like "thisisaverylongtesttitle" and is then doing a search for "thisisavery" but with no results. I can with a search for "thisisaverylongtit" get the result. But why not with a shorter search criteria? Is there a limit somewhere in the config?

Tried using the star operator and that helps, and I get the correct results back. But then the score is messed up (always 100%). Can you change this so that it keeps its score despite of the star operator, could this be a way to go. But how?

Anyone?