[Ludikraut]

Originally Posted by sscottttt

...Does anyone have any info on making the diffuser wider towards the back and angling the strakes so that they are further apart at the back than the front. It seems to be done this way on prototypes and f1 cars, I think this would "diffuse" the air even more, creating an even greater low pressure area and more downforce. ...

It's a possibility, but ... a diffuser does not generate downforce by "diffusing" the air. It helps to reduce drag by slowing the (hopefully) fast moving air coming from the undertray before it exits from the rear of the car into the car's wake. The effectiveness of the diffuser is directly related to how fast the air coming into it is and how much of a wake (determined by type of rear wing, shape of car, etc.) is behind the car. If you get it just right, you will gain a little bit of downforce in addition to the reduction of drag. I think the reason for the shape of the pictured F1 diffuser is to get the air spread out (diffused) evenly across the width of the rear wing to maximize the reduction of drag. I would also think that if you're running a big wing on your Evo, then you'd want a slightly steeper rear diffuser, and possibly tapered out slightly - whereas if you're just running a duckbill or trunk lip, then you'd want a flatter, straighter diffuser. The other potential issue with a flared diffuser is the air from the wheels, as it will be harder to keep it out from under the sides of the diffuser.

l8r)