Quote:
Originally Posted by humfrz
Hi ya, paulca
Your figuring appears to be accurate ........ 
However, the values I used are a bit different.
I used:
160 WHP (averaging several values reported on the internet)
density = 1.3
Cd = .27
frontal area = 21.2 sq. ft. (figure published by Car & Driver)
Plugging those numbers into the formula, my abacus gives me a calculated top speed of a stock 2013 FR-S, of roughly ......
157 MPH.
(I think your estimated frontal area of 2.28 m squared is a bit high)
Your thoughts ......?? |
I think we are dealing with theoretical aero drag limit. It would be interesting to plug in the equation for tyre and bearing drag or "total mechanical resistance" and see how that modifies things.
As my previous post (link) highlights, particularly in US and Europe speedometers are usually out by up to 10%, usually reading over, often deliberately to prevent owners suing manufacturers. Coupled with the only confirmed reports being of 149mph
indicated (in Germany) could suggest the max top speed actually demonstrated is 149 - (149*10%) = 149-14.9 = 135 mph.
I recall the original published figure from Toyota was 137mph.
As to the electronic limiter suggested above, I believe this is far more likely to be wind with changes in wind speed causing sudden drops in the cars velocity as the power in versus aero drag out equation suddenly unbalances and the car slows.
I believe the electronic speed limiters used as an agreement between German auto-manufacturers to stop the ever increasing autobahn top speed wars in the 1990s is set to 155mph.