Quote:
Originally Posted by MulsanneMike
The 300 hp quoted doesn't seem reliable. Simple calculations for hp absorbed given the top speed achieved by the AMR-One requires a unrealistically low drag coefficient to achieve the 187 mph trap speed the AMR-One set in the first practice session. Calculating for hp absorbed using the 187 mph top speed and a frontal area of 1.71 m^2 yields a .cd of .37 from 303 hp. A realistic LM .cd for an open top car is approaching .6 (.57-.59), around .5 for a closed top car.
Working the other way and solving for hp and again utilizing the 187 mph top speed, 1.71 m^2, and a more representative .57 cd yields 468 hp at the wheels, about 520 hp at the dyno. Going "high side" and using .59 gives us 485 at the wheels and 539 hp before transmission loss.
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Mike revised his calculations and now estimates that the (detuned) Aston Martin engine produces between 465 and 502 hp:
http://www.mulsannescorner.com/newsmay11.html
Perhaps Sam of RCE just made a typo and meant
500 instead of
300 bhp.
To put things into perspective Mike estimates that the Judd 3.4 V8 produces around 570 hp and the Peugeot 3.7 V8 HDI between 594 and 609 hp.
BTW Mike also reveals why a number of engine manufacturers (including Aston Martin, Audi and Judd) quote 540 bhp as their official power output:
Quote:
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Looking at it another way, 540 hp is within 2% of the target the ACO set for everyone and is a convenient number for Judd to claim.
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Note that HPD and Toyota just say 500+ bhp.