Kia Seltos with “robot” 7DCT. Advantages and disadvantages
In anticipation of the premiere of Kia Seltos, the transmissions of the new car are being actively discussed on various resources. If mechanics and a classic automatic machine are one of the most anticipated options, then a variator and a robot raise a lot of questions. In the top-end Premium all-wheel drive configuration, Seltos comes with a 1.6 turbocharged engine and a 7DCT robotic gearbox of the D7UF1-2 modification, and it’s worth talking about it separately.
The robotic seven-speed dual-clutch transmission 7DCT is already known in our market. The gearbox was created by specialists from the KIA Research and Development Center in Korea, this is a completely independent development of the company. The transmission was previously installed on KIA Sportage 4 GT-Line with 1.6 T-GDI engine, KIA CEED 2019 CD with 1.4 T-GDI engine and SOUL 3 from mid-2019. Now the turn has come to the new Korean crossover. Earlier than ours, Seltos debuted in India with such a box, and there are already first reviews from the owners, but first things first.
What kind of "beast" is the 7DCT, and what does Kia need it for?
When developing a new transmission, engineers always set themselves the goal of improving the performance of existing transmissions. The 7DCT was supposed to beat the six-speed classic automatic in terms of fuel efficiency by 7%, acceleration by 5% and add more sporty feel. This can be achieved through faster gear changes and the elimination of traction failures at the moments of transition from one stage to another.
DCT or Dual Clutch Transmission is considered to combine the basis of mechanical and automatic, but does it better and faster. The principle of operation is quite simple. It is like two manual transmissions shifting together. The transmission has two dry-sump clutches, each with an electromechanical drive and a two-gear input shaft. The hollow primary shaft works with even gears, and the solid shaft running inside it is responsible for odd gears. This arrangement allows you to switch gears as quickly as possible due to the fact that neighboring gears always have a pre-engaged state. The robot allows you to jump both up and down several gears at once, which allows you to accelerate sharply, or vice versa to reduce speed.
The continuous power delivery offered by the DCT minimizes transmission torque loss when shifting compared to a traditional automatic and provides a smoother ride in all conditions. The new DTC transmission is capable of transmitting up to 300 N.m. of torque, which is much more than the company’s currently used traditional hydraulic machines can "digest". Internally, a dual clutch transmission is more efficient than an automatic because it has fewer moving parts. Also, with an automatic transmission, the engine has to drive the pump and some energy is lost in the torque converter and clutch packs. All this sounds convincing and beautiful, but are there any disadvantages to the box?
Cons of 7DCT
There are not so many real reviews on the 7DCT box yet, but if we collect information from our and foreign resources, then two recurring problems have been identified. Some users had cases when the box switched only odd gears (1-3-5-7), in fact only one clutch worked. Such information was published on some Indian resources. Seltos debuted there back in August 2019 and has already sold over 50,000 vehicles. The variant with a 1.4 turbocharged engine and a 7DCT robot is one of the most popular in India. The problem was solved quickly by flashing the box. KIA reportedly issued a software update service bulletin for the Seltos 1.4T 7DCT with Supervision instrument cluster in December in India. The update takes about 30 minutes and fixes the problem of skipping gears.
The second problem is clutch overheating. Some owners complain that when they drive hard, the signal indicator often lights up. The problem is partially solved by the same software update, which simultaneously updates the firmware of the engine control unit, transmission control unit and dashboard.
In general, we can conclude that the stable operation of the box depends on the operating conditions. She’s really prone to overheating. This can happen if the vehicle is held uphill by depressing the accelerator pedal. In this case, the driver may feel a vibration in the steering wheel and the display on the instrument cluster will flash. The clutch will disengage until it cools down to normal temperature. To avoid such situations, it is recommended to hold the car with a foot brake.
Overheating can also occur during repeated actuations when the transmission downshifts during hard acceleration. This will change the driving mode of the vehicle and trigger a warning message. To return the car to normal driving conditions, it is recommended to avoid excessive sudden accelerations while driving.
By the principle of operation, this box is similar to all other preselective "robots". But unlike everything from the same DSG, the Korean box does not always try to turn on second gear in a traffic jam. At speeds up to ten kilometers per hour, she will meekly ride in first gear until the first clutch is overheated. On the one hand, this method eliminates jerks and constant shocks at low speeds, but on the other hand, if the traffic jam drags on for about thirty minutes, the overheating of the box makes itself felt.
But most of all, such a box does not like to slip, if it overheats, a warning will be displayed on the device panel, and the car will become motionless until the clutches cool down. These robots are built for fast highway driving and fuel economy, not bad roads and city traffic.
Is it possible to make a choice in favor of a robot?
Probably you can, in terms of comfort, 7DCT is not inferior to the machine. It outperforms it in terms of economy, smooth shifting, responsiveness and dynamics. Feels great on good roads and long distances. But like all dry clutch boxes, it suffers from overheating. This can lead to failure of the electronic control unit. Also, the 7DCT is not a durable clutch. Conclusion – reliability and durability depend on the operating conditions. During regular operation, there should be no problems. A big plus can be considered a five-year KIA warranty on their cars.