after thinking about what i could do differently if i wanted to have MORE fear of speed (in order to perhaps better understand what you might be doing), the main thing i came up with was how far ahead I look when i am going fast.
If you want it to feel like you are going fast, just look close to the front of your motorcycle, your car, your mountain bike, heck, even your feet when you run. The closer you look, the more random information you are asking your brain to process, which makes it FEEL faster. If you choose, on the other hand, to focus on the information what is truly important (the things farther off in the distance that you will actually have time to do something about) your perception of speed will be much less.
My wife noticed the other day how far ahead i look when i drive the car (fast) because i was pointing things out that were 2 to 3 times farther away than where she was focused. When i asked her to push her attention out farther, she agreed the pace seemed much slower (and she felt safer!).
The sense of speed in games like MOTO GP2 is actually pretty good, but unless you are REALLY engrossed in the game, it will be hard to recreate the panic reactions that arise when your mind knows something is at risk. (maybe you could pay someone to poke you with a cattle prod when you crash in the video game?)