The Diesel Sunny is powered by the 1.5L K9K common-rail engine. This 8-valve SOHC unit is the same engine found on the Fluence, Logan, and the Micra dCi. On the Sunny, the power has been bumped up an additional 20 BHP. The engine is rated at 85 BHP @ 3750 rpm, with a maximum torque of 200 Nm @ 2000 rpm. The Sunny manages to pull off an ARAI rating of 21.64 kpl (the Micra was 23.08). Pretty good considering the additional power it pumps out, as well as weight it has to pull along.
Now, this engine isn’t exactly what you’d call state of the art. It is however, a proven workhorse. Ask the driver of any commercially used Logan if he’s faced any engine problems in his 2+ Lakh kilometers of driving, and he’ll say no. This mill is tried and tested.
Crank up the engine, and there is a very noticeable shake. Instead of the side to side shake, it rocks the car in the front-back direction. It lasts for about a second or two at start-up, after which the car is vibration free. Even on a cold start, the engine is very quiet and refined on the inside. Surprisingly, its almost as quiet on the outside too. There is no metallic diesel clatter at idle.
Release the clutch, and the low end torque is instantly apparent. Most importantly (for city driving) there’s plenty of torque even before the turbo really spools up. Minimal turbo lag. You can even lug quite comfortably at a surprisingly low 800 - 1000 rpm in most gears. Just like the Micra it will lug at 40 km/h, 4th gear @ 1200 rpm – this is probably made possible by the ECU’s anti-stall feature which opens up the throttle slightly (you’ll feel a bit of acceleration once the revs drop closer to 1000 rpm). Cruising along at low RPM with light throttle, it barely sounds like a diesel. Even at 10 – 15 km/h in 2nd gear, you don’t hear any of that “loose” mechanical clatter. When driving, there is a noticeable purr from the diesel engine. It sounds almost like a petrol engine with a bit of a sore-throat (that too, audible only when you’re on the accelerator pedal).
2nd and 3rd gears are so versatile, that you never need to shift into 1st gear unless you’re at a dead halt. Power is fairly linear throughout the range, other than the slight jump in the power curve just past 1,800 rpm - when the turbo gets spooling. Make no mistake, the malleable nature of this engine does not mean that the Sunny is a particularly involving drive. It's still nothing like the Vento’s 1.6 TDI in terms of being fun to drive. In fact, for some strange reason, I felt like I enjoyed driving the less powerful Micra dCi more than the Sunny – perhaps the gear ratios and vehicle size at play?
When going up the revs the engine gets a little less eager at 4,200 rpm, but its still not at a point where its screaming at you, or really struggling to carry on – power tapers off very gradually. Even though the redline is marked at 4,500 rpm on the dials, the car will pull to about 5,100 rpm before the ECU actually cuts off the fuel supply smoothly. Windows open, and you can hear the turbo spooling away - as well as a whistle when you lift off the throttle.
From our drive, it seemed like the gear ratios were spread out a bit unevenly. The difference between 1st and 2nd is quite small, or rather, it seemed like 2nd gear was quite short. 1st gear would top out at 40 km/h, 2nd at 80 km/h and then 3rd all the way at 125 km/h. This isn't something that will cause any sort of inconvenience, but it did seem a little strange.
Given that the Sunny isn’t aimed at enthusiastic drivers, and more so at the average driver and back seat passengers – does the engine do the job? Yes indeed. It’s quiet, refined, has enough power & driveability and should have the same proven reliability & fuel-efficiency we've seen in its other applications (e.g. Logan)
What works against the Sunny Diesel? Well…
The brakes are not confidence inspiring. They do a decent job of stopping the car once they start to engage, but the pedal feels very dull and unresponsive for the first part of its travel. This isn’t free play in the pedal, the brakes just seem somewhat slow to react, and there’s no feedback from them.
Also, just like on the petrol Sunny the gearbox was still far from pleasurable to use. 1st and 2nd gears were definitely very notchy. Occasionally, getting the lever into gear would take some convincing.
Lastly, the engine’s NVH was well in control, however, road and tyre noise was quite noticeable. Naturally this is greatly dependent on the choice of tyres (Bridgestone B250s) and the road’s surface quality – but the noise levels seemed consistently high across a variety of surfaces, and started to get noticeable at speeds of 60 km/h and above.
The Sunny Diesel & Petrol are identical on the outside:
The higher-end XV variant that we tested
"Pure Drive dCi" badging looks nice
The huge rear legroom is apparent from the outside too
The tried and tested 1.5L K9K engine is fairly linear and doesn't suffer from turbo lag
The air intake sits well within the engine bay, thankfully the radiator is not in front of it (its offset to the side)
The battery has the "Renault-Nissan" badging
