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Rear Diffuser Design and Application

Old Aug 20, 2017 | 08:57 AM
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Default Rear Diffuser Design and Application

Someone can help more or chime in with there own opinion here if they want but I will give my take on what i recognize as incorrect design/options available for us C7 owners to purchase. There may be some available that I have not seen that could be IMO the correct design . OK, anyway every diffuser I have seen for sale design has the strakes/fins almost directly behind the rear wheels and nothing in the center under the exhaust where they should be to help direct the air flow that should be tunneled out from underneath the car and keep the turbulent air from affecting the cars handling, so what i'm seeing is the designs that are for sale have the placement backwards or fins/strakes towards outside blank in center, why have the designers done this is the question if anyone knows chime in, I would like to know, and I've heard before that they are for looks only but they could be effective if designed properly (fins/strakes in center).
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Old Aug 21, 2017 | 03:17 PM
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Look at the Borla web site but it will only bolt up to correctly if you have there cat back system on your car.

This is the only one I have seen with what you are talking about.
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Old Aug 22, 2017 | 12:55 AM
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How do you know that what they are doing is incorrect? I imagine diffuser design/layout depends a lot on the car it is mounted on. I am not an aerodynamics engineer so have no idea whether the diffusers offered in the aftermarket are designed for anything but styling but I doubt most people have any have any better idea than I do. Just because something looks good doesn't mean it is good.

Bill
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Old Aug 22, 2017 | 01:05 PM
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Originally Posted by Bill Dearborn
How do you know that what they are doing is incorrect? I imagine diffuser design/layout depends a lot on the car it is mounted on. I am not an aerodynamics engineer so have no idea whether the diffusers offered in the aftermarket are designed for anything but styling but I doubt most people have any have any better idea than I do. Just because something looks good doesn't mean it is good.

Bill
Plus looks like to me for this to truly help you will have to be pulling some high speed for a person to tell a diff with it are without it on the car. Robert
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Old Aug 22, 2017 | 02:17 PM
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I asked Tadge that question at Carlisle last year. The basic answer is no impact on performance.
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Old Aug 23, 2017 | 02:38 AM
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I never found before that is was incorrect. But if you have found, so maybe just share the solution. I rarely to use it as well.
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Old Aug 24, 2017 | 12:31 AM
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If you look at the supercars they do not have any fins in the center either. Here is a pic of the lamborghini centenario and 2nd pic is my diffuser I purchased for the BA look not for performance.


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Old Aug 25, 2017 | 08:00 PM
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A rear diffuser is window dressing on 99% of road cars, Corvettes included. Regardless of the presence of strakes or fins, to be effective a rear diffuser requires a flat underbody that is "very close" to the ground work to effectively. On race car diffusers the position of the strakes depend on the design of the car itself, like Bill Dearborn mentions above. The diffuser on C7R is a familiar example of design functionally optimized for results on that platform, however would look like **** and get beat to hell on street driven C7Z. If you like the look, purchase a diffuser that you think looks best and call it a win.


Last edited by NemesisC5; Aug 25, 2017 at 08:05 PM. Reason: Added picture
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