TWIN-SCROLL TURBOCHARGERS
The twin-scroll architecture of the turbos expands their performance capabilities, providing faster reaction and higher economy. Instead of a single spiral chamber supplying exhaust gas from the exhaust manifold to drive the turbine per each turbocharger, the twin-scroll design includes a split casing with two exhaust gas inlets and 2 nozzles to power the turbine. In speaking, one nozzle adds to faster reaction and increased output, while the other adds to total peak efficiency.
Each of the engine’s ejector manifolds/turbocharger casings separates the exhaust channels from the cylinder, sending the exhaust via various scrolls based on the engine’s exhaust pulses. When combined with proper valve timing, such separation optimises gas flow, increases turbine efficiency, and decreases turbo lag.
SPEED TRANSMISSION
The new Cadillac Twin-Turbo V-8 engine is coupled to a ten-speed transmission. Its broad overall gear ratio spread of 7.39 improves off-the-line performance and contributes to lower engine speed on the road, which improves refinement and economy. Smaller gear steps also assist the engine in maintaining the ideal speed for max output at virtually all vehicle speeds.
Direct fuel injection
To improve economy and performance, direct fuel injection is employed. Direct injection allows for a greater compression ratio – 9.8:1 — due to a cooling effect when the injected gasoline vaporises in the combustion chamber, lowering the charge temperature and minimising the risk of spark knock. A pair of camshaft-driven high-pressure fuel pumps installed on the engine feed gasoline to the specialised injectors at 5,075 psi (350 bar), with each pump giving fuel to one bank of the engine.
Active Fuel Management
In certain light-load driving circumstances, Active Fuel Management, commonly known as cylinder deactivation, silently shuts down half of the engine’s cylinders to improve fuel economy.
Oil jets
Oil jets placed in the block are used to manage performance and temperature. The engine’s 4 jet assemblies spray an extra layer of cooling, flexure oil over the bottom of the pistons and the surrounding cylinder. The jets lower piston temperature, allowing the engine to produce additional power while maintaining long-term reliability.
Stop/start technology
When the vehicle comes to a full halt, such as at a stop sign, stop/start system switches off the engine. When the driver removes their foot from the brake, the engine instantly resumes. During engine restarts, an auxiliary battery powers semiconductor switches such as the temperature system, power windows, and stereo.
Useful links
Visit eBay to buy remanufactured turbochargers.
Buy best remanufactured turbochargers on precisionturbos.co.uk.
Remanufactured Turbo Specialists NOT Reconditioned Turbos (precisionturbos.co.uk)
Volkswagen Transporter Twin Turbocharger 2.0 Bi-TDI Turbocharger CDCA CFCA
