If you go to the founders and threaten, they'll probably fire you. They got funding now so you're replaceable with somebody who will accept post-funding equity.
If you go to the founders and beg, they'll probably talk you out of it. They won't increase your compensation unless they see an increase in value.
If you go to the founders and say, "Tell me what I can do to really help the company" and then work like a dog to become an out-and-out performer, they may (repeat, may) appreciate your outperformance of the rest of the team and want to give you a big equity boost. It's hard to hate a total coding monster and you have to be a bad person to want to cheat somebody who will kamikaze himself for your company. Still, you have to do that for several years and really become the guy that they say, "If we only had three more guys exactly like him!" And, in the end, expect it to take years to build up a decent equity position and realize that they don't have to give you anything. And, of course, you've got to be a total coding monster.