[DeTomaso] Speed at 7,000 R's with

[Mad Dog Antenucci]

Hi Dan,
   
  I don't doubt your formula or calcs but I have to disagree from experience....I'm not being a smart ass but how much road do you know it will take to achieve a "similar speed" as you put it if after 10 miles straight away I haven't inched past 177 MPH? ;-]>
   
  I'm not talking about 'feeling the power loss'....I am talking about not having ENOUGH HP to overcome the negatives of elevation....its tough arguing with a Pantera God....You still be my hero source for all things related to Pantera-land.
   
  Dawg, who believes you STILL need a minimum of 600HP in a Pantera to get close to 200mph at Silver State....
   
    

Daniel C Jones <daniel.c.jones2 at gmail.com> wrote:
  > On TV this weekend they said that the average motor looses 3% of it HP for
> every 1,000 feet of elevation.

That's due to the air density decrease. At the same time, the aerodynamic
drag is also decreasing for the same reason, so it takes less power to
achieve the same top speed. A first order approximation estimate of a car's
top speed can be computed using the following formula:

/------------
15 / 1100 P
Vmax = ---- \ 3 / -------------
22 \ / Cd S rho
\/

where

P..........Power in rear wheel horsepower
Cd.........Drag coefficient
S..........Frontal Area in square feet
rho........Density of air in slug/cu. ft.
Vmax.......Speed in miles/hour.

If power decreases linearly with density, then the power decrease is
offset by the density decrease and top speed should be unaffected.
However, acceleration (which is dependent upon mass) will be reduced
so it will take longer to get there. When Mad Dog says he can feel
the power loss, it's the reduction in acceleration that he's sensing.
Given a long enough road, he should be able to achieve a similar top
speed but it will take much longer to do so.

Dan Jones
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Mad Dawg Antenucci 
Team Pantera Racing 
  The 1st & still the only vintage race team in open road racing 
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