Porsche Rear Diffuser
#2
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You can't really have true functional diffuser down there as the exhaust takes up a good portion of the rear underside. GT3 Tek has a diffuser look rear apron available.
#3
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A functional diffuser should be possible if you make a throat that is 24" wide and 16" long. This shouldn't interfere too much with the headers and allow air for cooling flow beneath the engine. You could put some 0.063 thickness aluminum angle 1.5" X 2.0" to create a funneling effect to the throat entrance as the air compresses and accelerates within. The expansion area could be 24" long and 29" wide to stay between the exhaust pipes. To flair outside the pipes and see if air extraction would improve downforce, you would need to flair to 39". The strakes would probably need to be no more than 2" from the ground to get much effect.
Just a few design notes from a drawing I made. I've yet to construct it.
Just a few design notes from a drawing I made. I've yet to construct it.
#4
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A functional diffuser should be possible if you make a throat that is 24" wide and 16" long. This shouldn't interfere too much with the headers and allow air for cooling flow beneath the engine. You could put some 0.063 thickness aluminum angle 1.5" X 2.0" to create a funneling effect to the throat entrance as the air compresses and accelerates within. The expansion area could be 24" long and 29" wide to stay between the exhaust pipes. To flair outside the pipes and see if air extraction would improve downforce, you would need to flair to 39". The strakes would probably need to be no more than 2" from the ground to get much effect.
Just a few design notes from a drawing I made. I've yet to construct it.
Just a few design notes from a drawing I made. I've yet to construct it.
#6
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A functional diffuser should be possible if you make a throat that is 24" wide and 16" long. This shouldn't interfere too much with the headers and allow air for cooling flow beneath the engine. You could put some 0.063 thickness aluminum angle 1.5" X 2.0" to create a funneling effect to the throat entrance as the air compresses and accelerates within. The expansion area could be 24" long and 29" wide to stay between the exhaust pipes. To flair outside the pipes and see if air extraction would improve downforce, you would need to flair to 39". The strakes would probably need to be no more than 2" from the ground to get much effect.
Just a few design notes from a drawing I made. I've yet to construct it.
Just a few design notes from a drawing I made. I've yet to construct it.
I still do not see a very practical way to do it on a regular street 996 with the m96 motor and stock exhaust(at least with the vertical strakes in place). Just from eyeing it, the engine/cats hang down a bit lower than the rest of the body work. I'm not proficient enough in aero to determine whether the rake of attack going backward will have any negative impacts.
Here's a few I've seen on 996 race cars or non 996 models:
![](http://www.team-bhp.com/forum/attachments/international-automotive-scene/266292d1263624532-porsche-911-gt3-r-m100009fine.jpg)
![](http://www.caradvice.com.au/wp-content/uploads/2008/02/rsr-rear.jpg)
![](https://www.speedhunters.com/wp-content/uploads/2013/09/SH_9FF_GTCS_new-19.jpg)
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#9
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Sharkwerks makes the cf one you see above for 997.1 which is pretty close but won't be a bolt on like you're looking for. Oh, and I don't know if you wanna pay $3k for that, especially for a 996 just for the fuhraze effect.
#11
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my $.02
#12
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A true design tested part is going to run you a lot more than 3k on a Porsche. I'm sure sharkwerks tested it. It doesn't mean they went full R&D with it. If they did it would show better gains and cost more money. I would imagine wind tunnel time isn't cheap. I never went that far into fluid dynamics but ab-flug isn't low quality when it comes to body panels
#13
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A true design tested part is going to run you a lot more than 3k on a Porsche. I'm sure sharkwerks tested it. It doesn't mean they went full R&D with it. If they did it would show better gains and cost more money. I would imagine wind tunnel time isn't cheap. I never went that far into fluid dynamics but ab-flug isn't low quality when it comes to body panels
AB Flug is a brand with a good rep and I've known them since they started but I wouldn't place my money on "style" parts if I'm gonna be paying north of $3k. Don't confuse the quality of the parts themselves with performance.
#15
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I interpreted as a bling piece since he said he saw one on the internet that "looked" awesome. Anyone looking to pay anything remotely close to $3k on a rear diffuser for bling on a 996 needs to have their heads examined imo. Of course there are peeps that pay up the wazoo for a carbon fiber wrapped piece so it wouldn't surprise me. I need to come up with carbon fiber lug bolts soon. I think there will be a demand if there isn't already.
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