Quote:
Originally Posted by jimepting
I've been interested for a while with this Bonneville fascination, but I must say I don't fully understand. It is true I suppose that at"level" top speeds of well over 100 MPH, ALL the power is going to overcome aero resistance. So one can make some calculations of Cd with reasonable accuracy. Is that the point?
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Bonneville is referred to as the 'Great White Dyno.' And along with the MPG/CdA relationship from GM Aero Lab,Hucho gives us the rule of thumb,that for a 30% drag reduction,we might expect a 10% increase in top speed.
Or,if no other variable exists,except the shape of a vehicle,then if you experience a 10% increase in top speed,then you must have reduced the CdA by 30%.
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If I achieve terminal velocity and I know the meteorological data during the run,along with engine rpm,I can deduce the available horsepower.
That horsepower will be the 'Road Load' at that velocity.
Since rolling resistance is already embedded within the relationship I should be able to reverse-engineer the new drag coefficient.
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BamZipPow's V-6 T-100 was tested by CAR and DRIVER and demonstrated a top speed of 96 mph,hitting an aerodynamic 'wall.'
I've had mine to an unofficial 115 mph with lots of throttle left.
From GM's relationship the Toyota is at around Cd 0.18 to achieve the mpg which it gets.
The top speed at Bonneville would allow me another back-door with which to figure Cd.We'll see.