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Love that spoiler!
 

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I know Blot and DevolvR have rear diffusers but other then them I haven't seen any others.
 

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I know Blot and DevolvR have rear diffusers but other then them I haven't seen any others.
But this looks so much nicer than theirs to be honest.
 

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You must be getting ideas from other cars like this one for example


Maybe it can be functional?
 

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You must be getting ideas from other cars like this one for example


Maybe it can be functional?
What your diagram is showing is just basically what a flat bottom diffuser does. It isn't creating downforce, it's just straightening air and eliminating drag. What a downforce derrived diffuser is designed to do is bring the top and the bottom of the cars airflow together more amicably than just shooting the air out the top and the bottom. Air traveling over the top of the car goes faster than the bottom of the car, essentially creating Bernoulli's Principles of Lift over the entire car. If you look at a side profile of a car, it is essentially wing shaped. The air going over the top of the car accelerates faster to meet the slower moving air under the car, which effectively pulls the car off the ground at a high enough speed. For years, car manufacturers have used wings, lips, splitters, etc to counteract this effect, and it works. But it creates drag, slowing the car down, lowering its top speed, etc. An even better thing to do is invert the profile, causing the air under the car to move faster than the air over the top of it, sucking the car to the ground rather than pulling it into the sky.

Companies like Ferrari, Lotus, etc have been doing this since the early 2000s. The back of a Ferrari's diffuser is much higher than the front; the diffuser makes it so that the air going under the car must accelerate to meet the air going over the top of the car, as the air on top has a shorter distance to cover and thus does not need to move as fast. This inverts the Bernoulli Effect and sucks the car to the road, effectively creating downforce without additional drag.



The way to make that diffuser in the diagram functional in terms of downforce or racing would be to actually eliminate a large section of the bumper, i.e. the area it says the air is getting caught in.



doing that would bring the top and bottom closer together and help to cause the bottom air to more closely match the velocity of the wind coming over the top of the car, reducing lift. On a conventional car designed without a diffuser from the start, you're not going to get positive downforce. A car pretty much has to be designed for it from the very start. This would go a long way to improving the aerodynamics though.

But the vast majority of "diffusers" and diffuser bumpers out there do almost nothing for downforce.
 
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