To change FOV you go to the console (the ~ key), and type "fov <the fov you want>" without quotes. Fov is the Field Of View, essentially what you can see. So normally you can see in 90 degrees around you, fov changes that degree to whatever you want, from 10 - 160. I suggest anywhere from 90-130, and just play with it, because different values make you seem like you are going faster or slower, but it really doesn't matter what you perceive your speed as, because thats just perspective.
-Cusoman