//Model
public class Car
{
   string name{get;set;}
   double speed {get;set;}
   //etc.
}

//Controller
public ActionResult ModifyCar(Car c)
{
    c = GetAdditionalData(c.name, c.speed);
    return View(c);
}

//View
@model Car
<form id="carform" method="post" action="/Car/ModifyCar"> //Guessing
    <input id="carName"  /> //Somehow bind with @model.name
    <input id="carSpeed" /> //Somehow bind with @model.speed
    <input type="submit" /> //Somehow send the model to the controller
</form>