Editing Turbocharger (section)

====Twin-scroll====
A twin-scroll turbocharger uses two separate exhaust gas inlets, to make use of the pulses in the flow of the exhaust gasses from each cylinder.<ref>{{cite web |title=Twin-Turbocharging: How Does It Work? |url=https://www.carthrottle.com/post/twin-turbocharging-how-does-it-work/ |website=www.CarThrottle.com |date=11 October 2016 |access-date=16 June 2022 |language=en}}</ref> In a standard (single-scroll) turbocharger, the exhaust gas from all cylinders is combined and enters the turbocharger via a single intake, which causes the gas pulses from each cylinder to interfere with each other. For a twin-scroll turbocharger, the cylinders are split into two groups in order to maximize the pulses. The exhaust manifold keeps the gases from these two groups of cylinders separated, then they travel through two separate spiral chambers ("scrolls") before entering the turbine housing via two separate nozzles. The [[scavenging (engine)|scavenging]] effect of these gas pulses recovers more energy from the exhaust gases, minimizes parasitic back losses and improves responsiveness at low engine speeds.<ref>{{cite web |title=A Look At Twin Scroll Turbo System Design - Divide And Conquer? |url=https://www.motortrend.com/how-to/modp-0906-twin-scroll-turbo-system-design/ |website=www.MotorTrend.com |access-date=16 June 2022 |language=en |date=20 May 2009}}</ref><ref>{{cite web|last=Pratte |first=David |url=http://www.modified.com/tech/modp-0906-twin-scroll-turbo-system-design/ |title=Twin Scroll Turbo System Design |publisher=Modified Magazine |access-date=28 September 2012}}</ref>

Another common feature of twin-scroll turbochargers is that the two nozzles are different sizes: the smaller nozzle is installed at a steeper angle and is used for low-rpm response, while the larger nozzle is less angled and optimised for times when high outputs are required.<ref>{{cite web |title=BorgWarner's Twin Scroll Turbocharger Delivers Power and Response for Premium Manufacturers - BorgWarner |url=https://www.borgwarner.com/newsroom/press-releases/2020/02/18/borgwarner-s-twin-scroll-turbocharger-delivers-power-and-response-for-premium-manufacturers |website=www.borgwarner.com |access-date=16 June 2022}}</ref>

<gallery heights="150px" mode="packed">
File:Mitsubishi twin-scroll turbo.JPG |Cutaway view showing the two scrolls of a [[Mitsubishi Motors|Mitsubishi]] twin-scroll (the larger scroll is illuminated in red)
File:Twin-scroll turbo T-GDI.jpg |Transparent exhaust manifold and turbo scrolls on a [[Hyundai Gamma engine]], showing the paired cylinders (1 & 4 and 2 & 3)
</gallery>