The Thrill of Diesel Part 1: A 2800km road trip in the Tata Altroz, Nexon and Harrier

What did you miss the most during lockdown? Eating out? The movies? Travelling without restrictions? Me? I missed driving. Covering uncountable miles on a big road trip. Banging in the laps on a racetrack. Kicking up dust on a rally stage. Getting the juices flowing, especially around this time of the year when we always have a big roadtrip to coincide with our anniversary issue. And so, when we were posed with the question, whether a magazine with #ThrillOfDriving on the masthead should still be banging the drum for diesel engines, we made a quick call to confirm if the MMRT in Chennai was operational. Turns out, it was never shut, and then the next task was identifying an appropriate spread of diesel cars with which to answer your question.

Now of course, many manufacturers have sacrificed diesel engines at the altar of BS6 emission norms and that considerably narrowed the pool of cars, while also fuelling this whole debate about diesels being dirty. The latter we will address in a bit, as for the former we decided to pick three of the more popular cars on our YouTube channel (judging by responses and comments), all conveniently from the same manufacturer, and all striking, in red — a coincidence, that!

The Harrier, I have always been enthusiastic about and the 2020 update sorts out the two big issues I had with it: the lack of an automatic gearbox and those massive wing mirrors. While they were at it, Tata Motors also added 30 more horses, re-positioned the USB slot and slapped on a massive panoramic sunroof. Next is the car that walked home with the gold trophy at our 2017 Car of the Year awards. For 2020, Pratap Bose and his design team have upped the Nexon’s styling ante while the engineering team have refined the already excellent chassis. And, also in red, is the Altroz, the newest in the Tata Motors range and one that aced our recent premium hatch comparison test. Ahead of us lay 1200km to Chennai, a full day at the racetrack, and another 1200km back to Pune. Can diesels be fun to drive?

But first… busting the myths

As India went into lockdown it also switched from BS4 to BS6, the most significant reduction in emission norms the industry has ever been forced to undertake; so significant that many manufacturers found it too expensive to clean up their diesels and just killed them. As far as emissions go, the two parameters that influence the Air Quality Index are particulate matter and NOx. BS6 norms have slashed diesel PM by 82 per cent from 25 to 4.5mg/km and NOx by 68 per cent from 250mg/km to 80mg/km. Of course, NOx on petrol emissions have gone down, from 80mg/km to 60mg/ km but the gap between petrol and diesel emissions have narrowed down significantly, including HC and CO levels.

But, can they be fun? Especially when most BS6 diesels are down on power and torque compared to their BS4 versions, while also being more expensive. To the best of my knowledge, Tata Motors is the only mass manufacturer to have extracted more power while making the switch, the Harrier up by 30 horses. To meet emission norms the Harrier now gets a diesel particulate filter (DPF) along with Selective Catalytic Reduction and a separate urea tank with a level gauge on the MFD. The smaller 1.5-litre diesel engine in the Nexon and Altroz use a Lean NOx Trap (LNT) to meet BS6 norms. But whatever the tech, one thing that hasn’t changed is the fuel efficiency and consequently range that diesel engines deliver — and that also means they emit lower grams of CO2 per kilometre. Diesels, then, aren’t dirty!

Leave early!

Rule number one of any road trip is leave early, preferably before the crack of dawn. You skip all the traffic, get a beautiful sunrise for the ’gram, and make great time before breakfast.

Rule two — it isn’t about top speed. The focus has to be on maintaining a consistently good average speed and the only way to do that is to have fewer stops. If there’s one thing I’ve learnt in all these years it is that 100-120kmph is the optimum cruising speed for Indian highways. The engine is unstressed and thus inaudible; you can relax behind the ’wheel; there’s more time to react to random stuff that will, unfailingly, jump across the road; braking distances and close shaves are reduced; passengers aren’t howling at you; and you won’t have to stop that often — to tank up, rest your brain, or let passengers throw up. Plus, that 120kmph buzzer fitted on all new cars can toast your brain cells on a 12-hour drive, though on that front Tata Motors has nailed it. The buzzer is audible enough that you notice what speeds you are doing, but not crazy loud to make the roadtrip miserable.

And as for fuel stops, well, the great efficiency of these diesel engines means the cars keep going on and on. Tata Motors claims a best-in-class fuel efficiency of 25.11kmpl for the Altroz and in the real world, over 1000km, it delivered 21.5kmpl. While this is purely on the highway, I have to also say that this isn’t on an 80kmph, air-con switched off, fuel economy drive. This is us driving to make an 8pm dinner reservation in Bangalore and accounting for all the stops for pictures and filming. On the same run

the Nexon delivered 20.3kmpl and the Harrier, with the automatic gearbox, did 14.4kmpl. That means you only need to tank up twice for Pune to Chennai, with enough diesel left in the tank for a day at the track. This is not the first time I am advocating the strength, relevance and suitability of diesel engines. You get the power to maintain a fast clip, torque, so maintaining said fast clip is effortless, great range courtesy very good efficiency, and thanks to BS6 they are cleaner than ever. But, of course, you don’t read this for fuel efficiency figures so stay tuned for part two to find out whether these cars can thrill on the road as well.