Twin-scroll turbocharger designs have two exhaust gas inlets divided by split walls inside the turbine housing, with both gas passages controlled by a waste-gate. A twin-scroll turbo recovers even more energy from the exhaust than a single-scroll turbocharger, thanks to a divided manifold. The twin-scroll design separates the cylinders whose exhaust gas pulses interfere with each other, resulting in improved pressure distribution in the exhaust ports and a more efficient delivery of exhaust gas energy to the turbocharger’s turbine.
For example, at the start of the intake stroke of cylinder one and when both the intake and exhaust valves of cylinder one are open (valve overlap period), cylinder three already starts its exhaust stroke with the exhaust valve open. If the exhaust passages of cylinder one and three were connected, the exhaust gas pulse from cylinder three would increase the back pressure of cylinder one. This would reduce the induction of the fresh air and increase the amount of hot residual gases inside the cylinder. However, with the twin-scroll turbocharger setup, this interference is minimized.
The result of this superior scavenging effect from a twin-scroll design leads to better pressure distribution in the exhaust ports and a more efficient delivery of exhaust gas energy to the turbocharger's turbine. This in turn allows greater valve overlap, resulting in an improved quality and quantity of the air charge entering each cylinder. In fact, with more valve overlap, the scavenging effect of the exhaust flow can literally draw more air in on the intake side. At the same time, drawing out the last of the low-pressure exhaust gases help pack each cylinder with a denser and purer air charge. Maximum boost from the turbocharger is 18 psi.
Thanks to the integrated stainless-steel turbine housing with the exhaust manifold, not only is the weight and cost of the casting dramatically reduced, the durability of the turbine housing is also improved. In addition, heat energy recovery and thus turbo efficiency is significantly improved based on the fact that a traditional two-piece design effectively insulates some of the heat energy at the joint/gasket area.
By adapting the motor-driven electrical waste-gate, the boost pressure is precisely controlled. The back pressure is reduced when turbo boost is not necessary by opening the waste-gate, which improves fuel efficiency. During cold starts, the waste-gate remains open, which results in faster catalyst light-off for reduced exhaust emissions.
A GDI fuel delivery system contributes to improved fuel efficiency and lower emissions. This shorter, more direct path of fuel delivery allows for greater control of the fuel mixture at the optimum moment, thus improving efficiency. The fuel is injected by a camshaft-driven, high pressure pump that operates at pressures up to 2175 psi. Direct injection also utilizes a higher-than-normal 9.5 compression ratio, while achieving a best-in-class 125.6 horsepower-per-liter. The piston heads are “dished” to increase combustion efficiency in the cylinder.
Veloster Turbo’s unique design takes inspiration from a custom high-performance sport bike. One of the most popular sport bike upgrades is to modify the exhaust. Hyundai designers have removed the Veloster’s trapezoidal center exhaust and replaced it with two larger free flowing circular pipes. These new pipes and the new intake manifold also allowed engineers to give the engine a more robust sound, which will delight enthusiasts.
From a bigger, bolder hexagonal front grille, through the sculpted side skirts and new dynamic rear bumper with prominent diffuser vents in the lower fascia, Veloster Turbo’s design adds aggression and aerodynamic stability compared to the base model. Drivers following Veloster will also notice the Veloster Turbo will be available in a Hyundai first Matte Gray paint. A set of 18-inch gray wheels with chrome inserts completes the Veloster Turbo’s recognized style. Veloster Turbo’s face also has signature eight individual headlight LED accents.
Working in harmony with the aggressive appearance is the finely tuned suspension setup of the Veloster. Only key components in the steering were upgraded for the Veloster Turbo. Veloster Turbo features a quicker ratio steering rack and a revised steering calibration to match, which both give drivers precise cornering, feedback and control. All Veloster Turbo’s ride on Kumho Solus KH25 215/40R18 85V tires designed to extract the best performance out of the car without compromising the ride.
All Velosters are fitted with a McPherson strut front suspension, coil springs, gas shock absorbers and a 24 mm diameter front stabilizer. The rear suspension is a light-weight V-torsion beam, a Hyundai-first with an integrated 23 mm stabilizer bar to allow bracing of the arms for greater stiffness and to further control body roll. The rear suspension also uses monotube shock absorbers for ride comfort.
All Velosters feature electric power steering that adjusts assistance instantly to changing driving conditions while improving fuel economy over a conventional steering system. Veloster’s turning diameter of 34.1 feet is better than Mini’s 35.1 feet and Mini Clubman’s 36.1 feet.
Inside, full leather seats with the word “Turbo” stitched into the seatbacks help deliver a unique look and provide exceptional support and comfort. An exclusive Supervision Cluster offers the driver information in a larger, clearer and more interactive format. This is due to the Supervision Cluster’s two TFT screens located between the tachometer and the speedometer. Heated front seats are also standard on the Turbo version. The center stack and controls also resemble a sport bike fuel tank and incorporate a push-button starter and alloy pedals.
To handle the power enhancements and keep with Hyundai’s commitment to making fuel efficient vehicles, Veloster Turbo is paired with a standard six-speed manual transmission or a six-speed automatic transmission. Both transmissions were developed in house at Hyundai. The manual features a wider gear ratio spread (5.71 vs. 5.25) to handle the additional torque output. The high-revving turbo helps during acceleration, especially at highway speeds.
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