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Old 05-28-2014, 08:48 PM   #127 (permalink)
RiderofBikes
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Join Date: Apr 2012
Location: kansas city, mo
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Pantry Boy Supreme (pbs) - '04 Volvo S80 T6 Premier
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Quote:
Originally Posted by Thenorm View Post
i've always wondered about modern sedans. the rear glass transition always seems smooth enough. that I bet the air stays attached, even though its sub template and producing a low pressure zone (acting like an airfoil)

case in point is the new mercedes CLA which gets an absurdly low Cd and even the prius which is sub-template

So for your car, maybe all you have to do is extend the horizontal of the trunk out closer to template
I get what your saying, but i think 1 thing overlooked with cars such as these as well as talked about the (Pontiac Aztek), and I've tried experimented with an extended section off the trunk lid to match template + half Kamm, didnt work out as well tail + kamm or the Full Kamm ive had before. This car is well under template meaning it's just too low and short. because the low pressure zone has already been created with little influence at the edge of the trunk(being base model/no added spoiler) to help pressurization,(if any) for better flow.

Red=Fiesta, Yellow=Prius/maybe Volt too


While yes, the Prius has better boundary layer characteristics(because its a solid arch from start to finish). The Bens also has a more gentle curvature between the rear glass and boot hatch and a generous radi around the D pillars, WAY better than a rear glass coming down to the horizontal plane of the trunk... There is that pocket of turbulent air still swirling away.
This doesn't mean i dont have decent airflow stock, but with the centralized antenna there's a locked vortex down the middle of the rear glass so there is no constant pressure for a chance reattachment that far out and that low

Basically, im filling in that void where the vortex is and reducing the curvature between the glass and trunk profile by raising the "trunk height"... so to speak.
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