The Kia K8 3.5 Smartstream GDi V6 Automatic represents the top-tier engine and transmission offering for Kia’s full-size sedan, launched in April 2021. Positioned as the flagship trim, it aims to deliver a blend of performance and luxury within the K8 lineup. The K8, introduced as a replacement for the Cadenza in many markets, signifies Kia’s ambition to compete more directly with established premium sedans. This variant, with its 300 horsepower V6 engine and eight-speed automatic transmission, is designed to appeal to buyers seeking a refined and powerful driving experience. It is built on Kia’s N3 platform, shared with other Kia and Hyundai models.
Technical Specifications
| Brand | Kia |
| Model | K8 |
| Generation | K8 |
| Type (Engine) | 3.5 Smartstream GDi V6 (300 Hp) Automatic |
| Start of production | April, 2021 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 11.1-11.4 l/100 km (21.2 – 20.6 US mpg) |
| Fuel consumption (extra urban) | 7.5-7.7 l/100 km (31.4 – 30.5 US mpg) |
| Fuel consumption (combined) | 9.4-9.7 l/100 km (25 – 24.2 US mpg) |
| CO2 emissions | 160-165 g/km |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 5.5 kg/Hp, 182.9 Hp/tonne |
| Weight-to-torque ratio | 4.6 kg/Nm, 218.9 Nm/tonne |
| Power | 300 Hp @ 6400 rpm |
| Power per litre | 86.5 Hp/l |
| Torque | 359 Nm @ 5000 rpm (264.78 lb.-ft. @ 5000 rpm) |
| Engine layout | Front, Transverse |
| Engine displacement | 3470 cm3 (211.75 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | V-engine |
| Fuel injection system | Direct injection and Multi-port manifold injection |
| Engine systems | Start & Stop System |
| Kerb Weight | 1640-1650 kg (3615.58 – 3637.63 lbs.) |
| Fuel tank capacity | 64 l (16.91 US gal | 14.08 UK gal) |
| Length | 5015 mm (197.44 in.) |
| Width | 1875 mm (73.82 in.) |
| Height | 1455 mm (57.28 in.) |
| Wheelbase | 2895 mm (113.98 in.) |
| Front track | 1621-1626 mm (63.82 – 64.02 in.) |
| Rear track | 1627-1632 mm (64.06 – 64.25 in.) |
| Drivetrain Architecture | Front wheel drive, Internal Combustion engine |
| Drive wheel | Front wheel drive |
| Number of gears | 8 |
| Gearbox type | Automatic transmission |
| Front suspension | Independent type McPherson |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Tires size | 245/45 R18; 245/40 R19 |
| Wheel rims size | 18; 19 |
Powertrain & Engine Architecture
At the heart of the K8 3.5 is Kia’s Smartstream G6DIII 3.5-liter naturally aspirated V6 engine. This engine utilizes both direct injection (GDi) and multi-port fuel injection, optimizing combustion efficiency and power delivery. The dual injection system allows for precise fuel control across a wider range of operating conditions. The engine features a dual overhead camshaft (DOHC) valvetrain with continuously variable valve timing (CVVT) on both intake and exhaust sides, further enhancing performance and fuel economy. The engine produces 300 horsepower at 6400 rpm and 359 Nm (264.78 lb-ft) of torque at 5000 rpm. This power is channeled through a smooth-shifting eight-speed automatic transmission, designed for responsive acceleration and comfortable cruising. The transmission is calibrated to provide seamless gear changes and efficient power delivery, contributing to the overall refined driving experience.
Driving Characteristics
The K8 3.5 Automatic delivers a noticeably more spirited driving experience compared to lower-trim models equipped with the turbocharged four-cylinder engine. The V6 provides ample power for confident highway merging and overtaking maneuvers. While not a sports sedan, the K8 3.5 offers a satisfying level of acceleration and responsiveness. The eight-speed automatic transmission is well-tuned, providing smooth and timely shifts. The gear ratios are optimized for both fuel efficiency and performance, with a focus on providing strong low-end torque for everyday driving. Compared to a potential manual transmission (not offered with this engine), the automatic prioritizes convenience and ease of use, making it well-suited for long commutes and relaxed highway cruising.
Equipment & Trim Levels
The K8 3.5 Smartstream GDi V6 Automatic typically comes standard with a comprehensive suite of features, reflecting its position as the top-of-the-line trim. These include leather upholstery, heated and ventilated front seats, a large touchscreen infotainment system with navigation, a premium sound system, and a suite of advanced driver-assistance systems (ADAS) such as adaptive cruise control, lane keeping assist, and blind-spot monitoring. Optional extras often include a panoramic sunroof, premium interior trim materials, and a head-up display. The interior design emphasizes a luxurious and spacious feel, with high-quality materials and a focus on comfort.
Chassis & Braking
The K8 utilizes a front-wheel-drive platform with independent suspension at all four corners. The front suspension employs a McPherson strut design, while the rear features a multi-link setup. This configuration provides a comfortable ride quality while maintaining good handling characteristics. The K8 3.5 is equipped with ventilated disc brakes at the front and solid disc brakes at the rear, providing adequate stopping power for its weight class. The standard anti-lock braking system (ABS) enhances safety by preventing wheel lockup during hard braking. Steering is rack-and-pinion, offering precise and responsive control.
Market Reception & Comparison
The Kia K8 3.5 V6 Automatic has generally been well-received by automotive critics, who praise its refined driving experience, spacious interior, and comprehensive feature set. The V6 engine is often highlighted as a strong point, offering a smooth and powerful driving experience. Fuel economy, while not exceptional, is considered reasonable for a full-size sedan with a V6 engine. Compared to other trims in the K8 lineup, the 3.5 V6 offers a significant performance upgrade, but at a higher price point. It competes with other large sedans such as the Toyota Avalon, Chrysler 300, and Buick LaCrosse, offering a compelling alternative with its modern design and generous features.
Legacy
The Kia K8 3.5 Smartstream GDi V6 Automatic, being a relatively new model, is still establishing its long-term reliability reputation. However, Kia’s recent improvements in build quality and reliability suggest that this powertrain should prove durable. The Smartstream engine family has shown promise in other Kia and Hyundai vehicles. On the used car market, the K8 3.5 is expected to hold its value well due to its desirable engine and trim level. Its combination of performance, luxury, and technology should make it an attractive option for buyers seeking a well-equipped and refined full-size sedan.
