Unit 6 Performance Unit
What does it mean? Where did it come from? Horse Power What does it mean? Where did it come from?
Horse Power The term horsepower was invented by the engineer James Watt. Watt lived from 1736 to 1819 and is most famous for his work on improving the performance of stream engines. We are also reminded of him every day when we talk about 60-watt bulb.
Dynamometer You can easily convert torque to horsepower by multiplying torque by rpm/5,252 A dynamometer places a load on the engine and measures the amount of power that the engine can produce against the load.
horsepower divided by the weight Power-to-Weight horsepower divided by the weight Bugatti Super Sport 1200 4480 .268 2.2 $2.4m Hell Cat 707 4480 0.157 3.6 $70,000 Mr. E’s Evo 850 2700 .315 Fast $30,000 Caparo T1 575 1040 .553 2.3 $300,000
Volumetric Efficiency Volumetric Efficiency is a ratio (or percentage) of the quantity of air that is trapped by the cylinder during induction over the swept volume of the cylinder under static conditions. Volumetric Efficiency can be improved in a number of ways, most effectively this can be achieved by compressing the induction charge (forced induction)
2.0L 4G63T vs 7.0L - LS7 505hp 286hp Every 14.7 psi over atmospheric pressure doubles an engines volumetric efficiency.
Superchargers Force air under pressure into the combustion chamber (higher than atmospheric pressure) More air means more fuel can be added. This process is called
Roots Type Supercharger PROS CONS Cheap Parasitic Drag Quick Low end power Extensive heat (rubbing) TBD / Carb mount above Higher weight
Centrifugal Supercharger PROS CONS Small / Compact Low RPM boost Freedom of placement Engine Oil Required to cool Thermal Efficiency Parasitic load
Stock piston and rods can only handle so much Engine Internals Stock piston and rods can only handle so much Forged Connecting Rod Once the engines power level reaches a certain point, it must be rebuilt using forged internals!