the turbine reach a good operating speed quickly or at lower engine speeds without severely diminishing its utility at higher engine speeds. Twin-scroll turbocharger A twin-scroll turbocharger design uses two separate chambers to better harness energy from alternating exhaust gas pulses. The chambers' nozzles may also be of different sizes, to better balance low-rpm response and high-rpm output. Sequential twin turbochargers Sequential turbocharger systems use differently-sized turbochargers to decrease turbo lag without compromising ultimate boost output and engine power. Nitrous oxide Nitrous oxide (N2O) is mixed with incoming air, serving as an oxidizing agent to burn more fuel for supplemental power when a turbocharger is not spinning quickly. This also produces more exhaust gases so that the turbocharger reaches operating speed faster, providing more oxygen for combustion, and the N2O flow is reduced accordingly. The expense of both the system itself and the consumable N2O can be significant. Water injection For increased engine power, and to augment other benefits of forced induction, an aftermarket water injection system can be added to the induction system of both gasoline and diesel internal combustion engines. References External links http://www.greencarcongress.com/2005/08/inside_vws_new_.html Superchargers Turbochargers de:Twincharger