Engine Horsepower
Engine horsepower, abbreviated as EHP, is the estimate of engine horsepower after a quarter mile run using the trap speed.
Engine Horsepower formulas |
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\(\large{ EHP = W \; \left( \frac{ v }{ 234 } \right) ^3 }\) \(\large{ EHP = \frac{ W }{ \left( \frac{ ET }{ 5.825 } \right) ^3 } }\) (elapsed time) \(\large{ EHP = W \; \left( \frac{ s }{ 234 } \right) ^3 }\) (trap-speed) \(\large{ EHP = \frac{ \tau \;\; s \;(RPM) }{ 5252 } }\) (rotating horsepower) \(\large{ EHP_{change} = W \; \left( \frac{ v_2 }{ 234 } \right) ^3 \;-\; W \; \left( \frac{ v_1 }{ 234 } \right) ^3 }\) (determine increase in horsepower) \(\large{ EHP_{change} = \frac{ W }{ \left( \frac{ ET_2 }{ 5.825 } \right) ^3 } \;-\; \frac{ W }{ \left( \frac{ ET_1 }{ 5.825 } \right) ^3 } }\) (determine increase in horsepower with ET) |
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| Symbol | English | Metric |
| \(\large{EHP}\) = engine horsepower | \(\large{\frac{lbf-ft}{sec}}\) | \(\large{\frac{Btu}{s}}\) |
| \(\large{ET}\) = elapsed time (time to finish quarter mile) | \(\large{sec}\) | \(\large{s}\) |
| \(\large{ET_1}\) = initial elapsed time (time to finish quarter mile) | \(\large{sec}\) | \(\large{s}\) |
| \(\large{ET_2}\) = final elapsed time (time to finish quarter mile) | \(\large{sec}\) | \(\large{s}\) |
| \(\large{s}\) = speed | \(\large{\frac{ft}{sec}}\) | \(\large{\frac{m}{s}}\) |
| \(\large{ \tau }\) (Greek symbol tau) = torque | \(\large{lbf-ft}\) | \(\large{N-m}\) |
| \(\large{v}\) = velocity | \(\large{\frac{ft}{sec}}\) | \(\large{\frac{m}{s}}\) |
| \(\large{v_1}\) = initial velocity | \(\large{\frac{ft}{sec}}\) | \(\large{\frac{m}{s}}\) |
| \(\large{v_2}\) = final velocity | \(\large{\frac{ft}{sec}}\) | \(\large{\frac{m}{s}}\) |
