Hey I need to make a 3d speedometer for a car have a script for that works fine but rotate 360 degrees how i can amke it real

#pragma strict

var velocidade = 30;
static var origRotation : Quaternion;

function Start () { origRotation = transform.localRotation; }

function Update () {

if (Input.GetKey(KeyCode.W)){
  transform.Rotate(Vector3.forward * velocidade * Time.deltaTime);
}
else if (Input.GetKey(KeyCode.S)){
  transform.Rotate(-Vector3.forward * velocidade * Time.deltaTime);
}

else
{
transform.localRotation = Quaternion.Slerp(transform.localRotation, origRotation, Time.deltaTime);
}
}

hey nobody know the answer ? maybe i have to do it otherwise ? but i dont need to use gui thats something esle.

Thank you for your help.