My company does reviews once a year around April. That is also when raises are suppose to be discussed. The part that confuses me about this setup is there doesn't seem to be any opportunity to ask for big raises or promotions before budgets have already been settled which typically happens at the end of the year. So it seems that my manager will come to me with a ceiling on a raise with no way to push for something higher, even if my manager feels strongly about a higher raise as well. Should I warn my manager that I'll be expecting a large raise come review time? Should I just asl for a raise now? Should I wait for them to come to me with a raise in case its higher?

Just for context, I've been killing it this year  with receipts to prove it. The company has been doing very well. Also, I'm hitting my 4 year marker which is the typical time to switch jobs for a bigger raise.