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Old 03-10-2018, 05:56 PM   #8 (permalink)
kach22i
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I found an image of a Porsche 924 without the rear spoiler while looking for Audi TT with and with-out rear spoiler.

https://rennlist.com/forums/924-931-...ictures-4.html


As Maxwell Smart would say.............."Missed it by that much".

I can see why the later 924's and 944 had the rear spoiler.

A much greater discrepancy on the older 911 design, but with a Ducktail it's a different story. I know it's not the favored "attached flow", but it's a step in the right direction.

Porsche Says These Are the Best Wings Porsche Has Ever Made
https://www.roadandtrack.com/car-cul...nd-rear-wings/

Quote:
From ducktails to fiberglass to fold-out power, these are Porsche's five most interesting aerodynamic designs.
This Audi TT below is a few years later than the 2001 model, I think this retractable one allows air to sneak between it's bottom lip and the trunk lid. The result appears to be some smoke gets under there, perhaps a good thing, I'm not sure.

aerodynamics? - VW GTI Forum / VW Rabbit Forum / VW R32 Forum / VW Golf Forum - Golfmkv.com


The thing I worry about is water getting trapped in the joint of the proposed "Upper Duck". If vented or weeped at the bottom some flow similar to the Audi above could feed the cooling air intake vent. That's a pretty big "could be" at the moment.

Didn't someone in the forum build a scale model wind tunnel tester a few years ago?

Quote:
Originally Posted by aerohead View Post
I would caution against the upper spoiler.I'd be concerned that you'd kill any downwash that is currently available to the engine bay inlet.
It's a pretty strong fan, even the five bladed one I have. Discussions on replacing it with an electric fan were deemed unfeasible in the Pelican forum as the motor would be more powerful than a Prius electric motor. Updating my 5 bladed fan to a better cooling one would rob me of 5 hp, similar to lugging around an extra 50 lbs - no thanks.

My point is, as much as I've looked into the fan draw issue, I've never found a VW Beetle or Porsche 911 wind tunnel smoke study that included air being drawn into the engine bay. A great appointment for me, and even greater now that I'm pondering this proposal.
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You cannot sell aerodynamics in a can............

Last edited by kach22i; 03-10-2018 at 06:18 PM..
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