Perhaps the Vintage series people allow you to block open the hood and cut
vents, but I've never seen that in any of the cars of the era you are
simulating. ABSOLUTELY FORBIDDEN. But, there is not much anyone can say about
a little creative metal work repairing. The first TR-4A car I had to run in
Modified category did have a few creative workings going on.
Trust me, you can't tell MUCH by just LOOKING at the car. "One valid test is
worth 10,000 expert opinions". You will find that sometimes air is actually
moving in the opposite direction to which it appears it should flow. We found
this to be so true when working on the Nissan GTP body shape in the wind
tunnel.
----- Original Message -----
From: joe dirt
To: BOB KRAMER ; fot@autox.team.net
Sent: Saturday, March 05, 2005 12:21 PM
Subject: Re: aerodynamics question
The front of the Nascar cars are wedged shaped. Blocking off the grill, the
air just spills off over the hood. As for blocking off the brake ducts it just
spills off the sides of the air dam and flows down the side of the car. By
blocking off the the grill on the TR4 I can just see air becoming trapped
under the hood and just forming a bigger wall than before. I think leaving it
open and then prop the back of the hood up and/or add vents like on Jack's
car. I know there is not enough room under the hood, but you could always
tunnel the air flowing through the radiator and direct it under the car, or up
through the hood. You could always mess around with front airdams, but I'm
pretty sure vintage organizations look shly upon such things :) . Jack you
would probally find more of an advantage by running a removable tonneau cover.
If you are serious enough, you could always try to smooth out the underbody of
the car. Also a performance trick that is used on motorcycles and other!
race
cars, is to direct the exhaust at a low pressure area behind or under the
car/bike. The low pressure pulls exhaust gasses out. I really doubt that these
cars go fast enough before that idea comes into effect, but it is a thought.
-Bob Adams
BOB KRAMER <rkramer3@austin.rr.com> wrote:
With the NASCAR cars, the blocked off air goes over the car and provides
downforce via their finely sculpted bonnets. With the TR4, air blocked by
the grill will go where ever it can. I think that the air forced down would
add to the front end lift from the increase in air under the car. Air that
escapes up would do the same if it hits the front lip of the hood. With no
where else to go, you'd probably see some increase in whatever grill opening
there is . Maybe we can reshape the bonnet leading edge to get air over the
top and provide downforce?
Bob Kramer
rkramer3@austin.rr.com
----- Original Message -----
From: "Jack W. Drews"
To:
Sent: Saturday, March 05, 2005 11:32 AM
Subject: aerodynamics question
> Question for my fellow tech freaks.
>
> I understand that the frontal area that those little air molecules see is
> the total profile of the front of the car.
>
> I also understand that the shape of the front changes the wind resistance
> (pointed object versus a brick).
>
> my question is this: ignoring the cooling situation, if you replace the
> grille in a TR4 with a flat panel, does this change the aerodynamic
> resistance?
>
> The NASCAR guys tape off the front opening to go faster...........
>
> uncle jack
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