Familiar 1.3L diesel with 74 BHP & 190 Nm of torque. A comfortable fit in this big engine bay. Considering the Bolt's hefty kerb weight, the 89 BHP version of this engine should have been offered instead:
Under the hood is our national engine, the Fiat 1.3L diesel. Power is rated at 74 BHP (@ 4,000 rpm) and 190 Nm of torque (@ 1,750 - 3,000 rpm). While these figures are identical to the Swift, it is important to note that the Bolt develops its peak torque 250 rpm earlier (Swift = 190 Nm @ 2,000 rpm).
The Bolt is Tata's flagship hatchback and one of their 'comeback' cars. Thus, I'm disappointed that Tata didn't choose the 89 BHP VGT (
variable-geometry-turbo) version of this engine. The Zest is being sold with the 89 BHP diesel (thereby making logistics simpler) as was Tata's old Vista D90. As Moralfibre pointed out in his Vista review (
link), the motor was nicely tuned. To make a sale in the crowded hatchback space, the Bolt needs all the differentiators it can get. This is precisely why I also loathe the missing AMT option which would've made for India's 1st diesel AT hatchback! Undoubtedly, two glaring errors by the planning team here. That said, knowing Tata's obsession with innumerable variants, I'm optimistic that the Bolt will see the 89 BHP diesel & an optional AMT some day.
The black cabin is a nice place to be in. Interior space is generous, the dashboard is well-designed, part quality is acceptable and that touchscreen ICE is just wow. The driver's seat offers good support & the steering is nice to hold. However, those used to low-slung Japanese cars will feel that the steering is positioned too high. The tilt adjustment range is normal, but it starts too high (
truck-like in its topmost position) and therefore, won't go down too low. This is a throwback to the ol' Indica / Indigo days. Further, the clutch pedal's resting point is too high (again, an Indigo trait). This is an annoyance as you have to lift your left leg noticeably more than you would in any other hatchback. Another complaint is that the front seats don't slide as far back as 6-footer drivers would prefer.
You need to press the clutch pedal to fire up the engine. In your first 5 minutes with the Bolt diesel, what will stand out is its refinement. Tata's engineers have worked hard at lowering NVH inside the cabin and it shows. Engine noise is very well controlled on the inside. At city rpms, diesel clatter is at minimal levels and while cruising, you'd be hard-pressed to tell that there is an oil-burner under the hood. Moderator Aditya just returned from the Jetta facelift drive and he commented that the Bolt is quieter than the VW! One fly in the ointment would be the engine & drivetrain vibrations felt on the ABC pedals, especially the clutch. These vibrations are directly proportional to engine rpm. A second irritant is experienced when the car is idling. You can literally feel the air-con compressor kick in & out. The action is far from seamless, and a very mild but annoying jerk is felt at the front of the cabin when the compressor activates.
Tata has given the 1.3L diesel a practical state of tune. The Bolt diesel pulls well from low rpm. Many hatchbacks powered by the same engine suffer from prominent turbo-lag, but not the Bolt. Remember, this Tata develops its peak torque a full 250 rpm earlier than the Swift diesel. As a result, the engine has adequate torque in the 1,500 - 1,900 rpm range. While there is a noticeable surge in power delivery once you cross 2,000 rpm, the Bolt is certainly not 'dead' below that. The needle climbs sufficiently quickly from 1,600 - 2,000 rpm. You can easily cross speed-breakers in 2nd gear itself, without feeling any need to downshift to 1st. In fact, you rarely need to downshift to 1st, unless you come to a stop or an absolute crawl. The Bolt offers good driveability in urban conditions and you'll be using the gearbox a lot less than some competitors. The initial lot of gears are short; this helps driveability and also in getting around lag. Don't get me wrong, it's no Nissan Micra, yet the Bolt is rather competent in the city.
There is a surge in power delivery once you cross 2,000 rpm and the engine is in the
turbo zone. You feel a distinct tug after the revv needle crosses this point. But sadly, the Bolt diesel is no road burner and one of the main reasons is its heavy kerb weight. The Bolt's power & torque to weight figures are among the lowest from the segment. The diesel is adequately peppy in the 2,000 - 4,000 rpm range, but it's not fast. At best, you'll be keeping up with expressway traffic. It's on a fast highway where you'll remember my words and wish that Tata had chosen the 89 BHP tune. Like most other diesels, the 1.3L has nothing to offer past 4,000 rpm, where the torque curve starts falling. No point in high-revving diesel engines, you'll only waste fuel without really getting anywhere. For the times that you need the extra revvs (e.g. when overtaking), the 1.3L will climb to 5,200 rpm. While the engine is noisy at high rpms, it doesn't suffer from the excessive boomy noise that the Punto exhibits. To put the outright performance in perspective, it's certainly better than the Figo diesel, and on par with the Liva & Punto. Cars like the Polo 1.5 however will leave the Bolt in the dust.
This car is more suited to a relaxed driving style than a hurried one. It's best to drive the Bolt sedately, work the torque and shift up early. It's a commuter hatchback, not an enthusiastic one. The Bolt diesel can be a relaxed cruiser on long drives. In 5th gear, 80 kph is seen at ~1,900 rpm, and 100 kph at ~2,400 rpm. Engine, road & wind noise are well-controlled in these conditions.
Where this commuter diesel will impress owners is in the efficiency department. I wasn't driving with a particularly light foot, yet saw 14 kpl in the city. Cruising on the highway had the engine delivering over 20 kpl. The ARAI rating stands at 22.95 km/l (Revotron petrol = 17.57 km/l). With a fuel tank of 44 liters, you can easily manage a highway tank range of 700 - 800 kms.
The Bolt diesel utilizes
Fiat's Evo-II transmission. Interestingly, it feels lighter & smoother than the gearbox in Fiat's own cars, the Punto & Linea!! The Bolt's gearbox is nice to use. It doesn't require much effort to shift and isn't heavy at all. Even the slim & well-designed gear lever feels good to hold. That said, the gearbox doesn't have the finesse or sheer shift quality of the Hyundai i20 & VW Polo. I'll give it a 7.5/10 rating. The clutch pedal is very light to use. On the flip side, its travel range is way too long. As mentioned earlier, the pedal's resting position is too high as well, making it cumbersome to operate in rush-hour traffic.
As our Bolt petrol review indicated, the suspension is indeed firmer than the Zest's. While ride quality is still compliant, it's certainly not as cushy as that of the Zest. The Zest manages to glide over roads smoothly at any speed. On the other hand, the Bolt feels distinctly firmer. It's comfortable, albeit you are
always aware of the road conditions below you. Big bumps feel more pronounced & the sharp ones come in strong. On smooth roads & highway speeds, occupants won't complain. Do note that we drove the top variant with 15" rims; lesser trims with 14" wheels (
and thus, a taller tyre sidewall) will have softer ride quality. Must add that the suspension does its work silently. No thuds or the like when going over rough roads.
The Bolt is decent around corners too. At regular speeds, it has no problems tackling them. Only on throwing the car hard into curves will you see understeer stepping in. The diesel doesn't feel much different than the petrol, as the weight difference at the front isn't significant. Those 175 mm Goodyear Assurance tyres provide sufficient grip, while overall road behaviour is helped by the wide tracks (
1450 mm front and 1440 mm rear). That said, there is a fair deal of body roll which dampens the driving experience. Don't expect it to be a corner carver or involving handler in any way. The Bolt's handling is neutral and the average Joe will be happy with its safe dynamics. Want entertainment on a mountain pass? Look at cars like the Punto, Polo, Figo & Swift instead.
The new electric power steering developed by ZF is light & accurate. Like the Nano Twist, the EPS has an "Active Return" function which (Tata claims) makes the car less tiring to drive & park. It's light enough at crawling speeds. As the speedometer climbs, the steering weighs up properly. On the highway, there's absolutely no vagueness or twitchiness, which helps the Bolt feel planted. This is certainly one of the better EPS units around and they've struck the right balance. Tata adds that the Bolt's EPS uses a brushless motor which makes it more durable.
The braking hardware is ubiquitous; disc brakes at the front and drums at the rear. The 9th generation ABS unit is sourced from Bosch. Overall, the brakes have adequate stopping power. They feel & work as you'd expect in a hatchback from this price band. No surprises (good or bad) here.
The under-bonnet insulation blanket:
Reflective insulation sheets on the firewall. Just one of the contributors to the Bolt's excellent refinement levels:
The ECU sits right ahead of the battery:
Fixed geometry turbo-charger in plain sight:
You can clearly see the road below. Engine isn't fully protected from the underside:
Tata has organized & wrapped the wiring neatly. Nearly all wires are insulated. Also notice the plastic clip anchoring this harness to the body:
This cooling fan is LOUD & how! It creates quite a racket on the outside:
A big shoutout to Rehaan & Rudra Sen for post-processing the pictures!