a light pressurizing effect similar to a low-pressure supercharger due to Helmholtz resonance. However, this effect occurs only over a narrow engine speed range which is directly influenced by intake length. A variable intake can create two or more pressurized "hot spots." When the intake air speed is higher, the dynamic pressure pushing the air (and/or mixture) inside the engine is increased. The dynamic pressure is proportional to the square of the inlet air speed, so by making the passage narrower or longer the speed/dynamic pressure is increased. Many automobile manufacturers use similar technology with different names. Another common term for this technology is variable resonance induction system (VRIS). Audi: 2.8-liter V6 gas engine (1991–98); 3.6- and 4.2-liter V8 engines, 1987–present Alfa Romeo: 2.0 TwinSpark 16v - 155 ps(114 kW) BMW: DISA and DIVA systems Dodge: 2.0 A588 – ECH (2001–2005) used in the 2001–2005 model year Dodge Neon R/T Ferrari: 360 Modena, 550 Maranello Ford VIS (Variable-resonance Intake System): on their 2.9-liter 24V Cosworth (BOB) based on the Ford Cologne V6 engine in the later model Ford Scorpio Ford DSI (dual-stage intake): on their Duratec 2.5- and 3.0-liter V6s and it was also found on the Yamaha V6 in the Taurus SHO Ford: The Ford Modular V8 engines sport either the Intake Manifold Runner Control (IMRC) for 4V engines, or the Charge Motion Control Valve (CMCV) for 3V engines. Ford: The 2.0L Split Port engine in the Ford Escort and Mercury Tracer feature an Intake Manifold Runner Control variable geometry intake manifold. General Motors: 3.9L LZ8/LZ9 V6, 3.2L LA3 V6, and the 4.3L LF4 V6 in some second generation S10s and Sonomas GM Daewoo: DOHC versions of E-TEC II engines Holden: Alloytec Honda: Integra, Legend, NSX, Prelude Hyundai: XG V6 Isuzu: Isuzu Rodeo, used in the second generation V6, 3.2L (6VD1) Rodeos Jaguar: AJ-V6 Lancia: VIS Mazda: VICS (variable inertia charging system) is used on the Mazda FE-DOHC engine and Mazda B engine family of straight-4s, and VRIS (variable resistance induction system) in the Mazda K engine family of V6 engines. An updated version of this technology is employed on the new Mazda Z engine, which is also used by Ford as the Duratec. Mercedes-Benz MG: MG ZS 180 MG ZT 160, 180 and 190 Mitsubishi: Cyclone is used on the 2.0L I4 4G63 engine family. Nissan: I4, V6, V8 Opel (or Vauxhall): TwinPort – modern versions of Ecotec