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Hi everyone. Thought I would share my adventure with having a custom ducktail made for my 991.2. I always loved the ducktail. Had one on my 991.1 but had to let that car go. I missed my 991 so much I found a 991.2 the exact color. To my surprise there was no ducktail like the one for my previous 991.1! The OEM “ducktail” was nice but I really wanted a true old school ducktail, but none allowed enough air to get to the turbos. So…I went off the deep end and had one made. Here are the pics from the beginning. I am at the prime and paint stage now. Found this one on eBay but when it’s revived there wasn’t any way to get good airflow without deploying the wing. That would have looked ugly and caused way to much drag.
PROS: Appropriate temperatures maintained. Non restricted airflow. Downforce 150 lbs at 100mph with grip increase to 5.8%. No added wind noise. Finished product that I aesthetically enjoy!
CONS: Pricey! Total cost $5700. Took a long time to figure out the physics while not loosing the entire look of the ducktail. Form vs function balanced out but was at a cost.
LESSONS LEARNED: Air vents can be smaller by about 1.5cm in height if length maintained. Reinforced skeleton with fiberglass bolsters while closing off the interior upper part of the wing was imperative to achieve the proper flow to the turbos and allow then needed aerodynamic parameters due to eliminating excess drag and unwanted turbulence. Bottom
cutouts on the ledge allowed unrestricted airflow at speeds where OEM wing needed deployment. We couldn’t achieve that without those openings.
Took the wing to Modern Street Customs in Delaware to see what could be done. Here was the idea… Bottom support flange now with cutouts. Rear of ducktail Top of ducktail. Internal supports were added to strengthen the spoiler.
Going to use this mesh. Did a test fit and so far so good! Now it’s off to get primed and painted. Will post photos when it’s all done and let everyone know! Can’t wait to have the ducktail done and finally back for my 991.2!!
And also throwing on these custom champion wheels as my summer wheels and use the originals for winter. Thought the gunmetal would blend well with the midnight blue and tone down the polished deep aluminum lip.
Are the horizontal slots/holes that you cut out going to remain open like that? I like the design but am wondering about the amount of air sound (whistle?) that will be induced. I'm no auto engineer by any stretch so excuse my silly question.
Make sure you plug in the car and do some control runs (with the stock wing) at slow and high speeds reading real-time air/fuel mixtures, ect. Then do the same with the new wing. Things can get silently real hairy real quick.
Curious, why the cut-outs on the underside of the wing? Wouldn't using the ducktail as an air intake into the bay for the turbo intakes make more sense? The way the wind will go over the rear it's not like it's full force of air into the slots, and closed underside may help suck in that static air around there.
Porsche did it with the Sport Classic and I have no idea why no aftermarket company can figure this out.
They had to redesign the actual body. If you notice, they had to remove hip vents and make a one-off cooling setup for that special edition just for the ducktail. So that SportClassic has a one-off turbo body.
From the Porsche Newsroom:
"The most significant design elements can be seen at the rear of the car. Here, the wider rear fenders of the 911 Turbo gain even more visual emphasis. Where those panels usually have large cutouts for air intakes associated with the 911 Turbo, the 911 Sport Classic has no such intakes. This creates a large, smooth surface and a very clean appearance. It might seem like a small change, but deleting the intakes required significant engineering work, and new tooling to stamp the panel, which runs from underneath the front of the car doors to the rear of the vehicle. Due to the eliminated air intakes, ducts underneath the ducktail spoiler channel combustion air to the engine while charge air continues to route through the grille above the engine for cooling."
I'm aware of what they did and that is my exact point, the inter cooler intakes are under the duck tail we do not need the side intakes at all so that's mute point. I'm only talking about the ducts under the ducktail which the OP has done although in a slightly different way.Wasn't talking about the entire package.
The intercooler intakes are under the wing, when closed the air flows is fairly restricted and when IATs increase the wing raises to allow better flow to the intercoolers. The SC ducktail has an opening at the bottom, regardless of where that air flow is going on the SC all we need is a ducktail that allows airflow to the intercoolers with an opening the bottom of the intake like the Sport Classic "bottom of duktail" intake.
All the current "ducktails" for the 991.2 do not offer this thus need to raise the entire duck tail to get airflow to the intercoolers.Which looks horrible.
Make sure you plug in the car and do some control runs (with the stock wing) at slow and high speeds reading real-time air/fuel mixtures, ect. Then do the same with the new wing. Things can get silently real hairy real quick.
Curious, why the cut-outs on the underside of the wing? Wouldn't using the ducktail as an air intake into the bay for the turbo intakes make more sense? The way the wind will go over the rear it's not like it's full force of air into the slots, and closed underside may help suck in that static air around there.
The computer showed less drag with the opening on the rear of the wing and when we added the openings on the bottom deck where it attaches above the louvers it allowed excellent airflow just like when the OEM wing is deployed. So air flowed through the wing to reduce drag, gave enough downforce without having to worry about lifting the front (although at street speeds really not an issue), and allowed air to get to the grill on the intake for the turbos without hindrance. I tried smaller openings but couldn’t get the temperature variations where we needed them. This appears to keep the engine cool when needed and not choking the turbos. Remember taking off the OEM wing would be best from an engineering standpoint and leave a big hole even though this would alter aerodynamics a bit. It would be unsightly so Porsche needed a wing to maintain aesthetics but it limits what can be placed and how the wing would have to be deployed. I’m hoping this answers it. If not, then experiment failed and I put the OEM wing back on! Hopefully not as all the math is working so far!!!
Porsche did it with the Sport Classic and I have no idea why no aftermarket company can figure this out.
Rennline has promised a 991.2 Ducktail before the end of the year. I have been harassing/encouraging them for quite some time now and most recently at RennSport Reunion.
10-04-2023, 11:39 PM
Custom Ducktail 991.2
