[brucepick]

I think this has potential.

EDIT: [I just saw Frank's post, which went up while I was writing mine. If this topic is already addressed and "laid to rest" as not significantly helpful, then that pretty much wraps it up. HOWEVER, if there is gain, it looks like low hanging fruit - you probably could build a full-width version as I described below pretty quickly and easily.]

I think that though you're calling it a splitter, most of the air it affected is going up over the windshield without really hitting it. Which I think is a good thing, and more helpful than if you had split the air off to the sides.

I'm guessing this from the "sunburst" pattern on each side of the windshield. If the air had been split, each side of the windshield would have a set of more parallel streak lines, going either up the windshield or maybe off to the side. But not a sunburst pattern.

So you've helped the flow of the air going up the middle of the hood. That's my guess.

So to get more benefit, widen the device out to the edge of the hood, or even out over the fender if you can make that happen. My idea is to scoop most of the air off the hood so it skips over the windshield. Keep the top rear low enough so that even a driver shorter than you can still see the same line down over the hood's forward edge.

And to keep it safe in a collision, make it out of coroplast. So if the hood flies up, or if your mod flies off the car, it doesn't cause damage. You might have to make it collapsible or removable, just so you can check the oil.