At the risk of treading on more informed toes, I think without benefit of a
full tonneau cover, the car without the top suffers from a significant low (or
perhaps high, I don't remember this too well) pressure zone created by that
great big hole where the driver sits whereas the tin top has minimally
disrupted flow over the cockpit. Probably be faster still with the windows
closed.
As I said, this is taxing my memory so I stand ready to be corrected by all
you closet aerodynamicists lurking on the list.
Rob McCurdy
Lola 322
Irv Korey wrote:
> > From: Jack W Drews <vinttr4@geneseo.net>
>
> > We are both surprised that performance is identical -- wouldn't you
> > think that acceleration out of corners would be better with Joe's lower
> > weight, and shouldn't he also have a higher top speed, with the lower
> > frontal area?
>
> While Joe's car has a smaller frontal area, in my unscientific experience,
> top down TR's are LESS aerodynamic than your car with the hardtop. This
> observation has been made over many years and many road trips in my street
> car TR6. Top down on the highway, the car gets around 23-24 mpg on a road
> trip. Top up (heaven forbid), the mpg is in the 27-28 range. What else
> could it be than aerodynamics?
>
> Irv Korey
> Highland Park, IL
> 74 TR6 CF22767U
> TR4 CT52499 (almost ready vintage racer, no hardtop)
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