It might be something to do with fuel. pump could be going out. If the motor is stock it could be one of those things, and if you have a vtec controller, did you mess with the engagement settings?
Here's what ya do: Put the fuel correction at 0. Set VTEC back to 5800. And go get the fucker dyno tuned. I'm not saying that will fix your bogging pronlem altogether, but it wouldnt hurt. You havent fucked with the fuel pressure have you? It sounds like you're running really rich at the VTEC crossover.