turbocharger
- not a normally aspirated engine
- driven by exhaust flow
timing components
- some have adjustable gears to advance or retard timing
valves
- engines can have 2, 3, 4, or 5 valves per cylinder to improve engine breathing
- changes in camshaft lift rate, duration and overlap are from lobe design
variable timing
- adjusting the exhaust lobe doesn't improve torque
supercharger
- increases the density of the air in the cylinder
- when installed on a carbureted engine the system can be either a blow through or a draw through
- Pressure wave, axial flow, and centrifugal flow are all dynamic superchargers
high performance engines
- can cause poor low rpm performance
- performance components must be properly matched, just installing some performance components can cause a performance loss
- restrictor plates block off some of the intake air flow in racing engines
- intake manifolds
cylinder heads
- porting is altering the size of the passage
- polishing is smoothing the metal surface
- cross-flow heads improve engine breathing
engine efficiency
- thermal efficiency is how well the engine converts heat to usable work
- thermal energy of gasoline is 19,000 btu per pound