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Old 07-16-2012, 08:23 PM   #23 (permalink)
some_other_dave
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Quote:
Originally Posted by orange4boy View Post
I find it hard to believe that the drag is greater with the fastback but we don't know the angle so perhaps it is more than the ideal of ~12-15 degrees
I don't know about the angle, but there are other considerations. For instance, at speed there is air flow going forward along the rear deck. I guess this is where the cooling and induction air come from? I have seen a number of photos and even a video or two of tuft testing done on 914s over the years that show this. It's pretty counterintuitive, but the tufts clearly showed rear-to-front air flow.

The water-cooled conversions don't have that problem, but they generally have air flow coming in through the front panel and exiting either under the front or out of the front wheel wells. None of which is that good for the car's aero.


EDIT:

Oh, and I averaged about 34 MPG two weekends ago. Over about 600 miles, at freeway speeds, including some mountain climbing. (I-80 from SF to SLC.)

-soD
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