Suggestions for increased caster angle.

[Salt Racer]

Changing the pitman arm length will change your overall turning radius but won't do anything for your steering ratio.

Denny,
Think how longer pitman arm changes turning diameter. Longer pitman reduces turning diameter b/c tires turn more for a given steering wheel input. The pitman arm converts rotational motion of steering gear box into linear displacement of drag link. So for a given input angle at the splined shaft, the output linear displacement of drag link is greater with longer pitman arm. So it indeed changes overall steering ratio (steering angle @ tire per one rev @ steering wheel).

Conversely, steering arm on knuckle will revert the linear motion back into rotational motion. So shorter the steering arm, greater the steering angle @ tire you'd have, again for a given drag link displacement.



Of course, when you mess with one thing, something else will be affected just like any other things in suspension/steering system. You'll have to take stuff like stress in linkages, change in Ackermann angle, effort if manual steer, etc, into account.