Horsepower from Quarter-Mile ET

HP = weight x (5.825/ET)^3 inverts Hale's ET relation. A 3,200 lb car running a 12.63 s quarter made ~314 hp; a quicker 11.5 s ET implies ~416 hp - the cube law. ET is what a timeslip gives directly, but it is corrupted by traction and the launch (spin or bog runs a slower ET at the same power), so trap speed is the cleaner indicator when available. Empirical fit, wheel power, not a dyno. A hobbyist estimate; the dyno governs.

HP = weight x (5.825 / ET)^3 (the inverse of ET = 5.825 x (weight/HP)^(1/3)).

Hale's empirical quarter-mile ET relation ET = 5.825 x (weight/HP)^(1/3) solved for power, the ET companion of the trap-speed tile, as compiled in the drag-racing references, by name.

Hale's quarter-mile relations are public empirical results widely used in the drag-racing community.

Estimate. AHJ and licensed professional govern.

Field names used by the API: weight_lb, et_s, hp

• ET power HP = weight x (5.825/ET)^3, the inverse of the ET cube-root relationHale quarter-mile relation
• Trap cleaner ET is corrupted by traction and the launch; trap speed is the cleaner indicator when availabledrag-racing practice
• Empirical a statistical fit reflecting wheel power; not a dyno measurementdrag-racing practice