[gsracer]

Ok so i need to make the throat wider and lessen the angle the throat say down to 15 degrees, as for the flat portion on either side of the throat. It may not look like this in the pictures but its pretty much parallel to the floor with a rise in the back of maybe 4 degrees.

Now two more questions. The throat of the diffuser is smaller towards the diff and wider towards the rear, is there an optimum angle for this, and lastly im totally lost on the rouded edge towards the diff, do you mean rounded horizontally or rounded verticlly (ie a lip at the entrance).