Tata Motors has readied a brand-new 1.5-litre 4-cylinder naturally aspirated (NA) petrol engine that will make its debut in the Tata Sierra. While the upcoming 1.5-litre direct-injection turbo-petrol showcased at Auto Expo 2023 has been the headline act, it’s the simpler, naturally aspirated version that could end up being the real sales driver.
- New 1.5-litre NA petrol expected to produce around 120hp
- Sierra will get both 1.5-litre NA and turbo-petrol engine options
- 1.5-litre NA petrol will help achieve an aggressive starting price for Sierra
Sierra 1.5 NA petrol to make up the bulk of volumes
The new 1.5 NA engine, a derivative of Tata’s 1.5-litre direct-injection turbo-petrol, shares its basic architecture – including bore spacing, block and head design – but ditches the turbocharger and high-pressure injection system in favour of a port fuel injection setup. This configuration helps reduce manufacturing costs and complexity while improving fuel efficiency.
Crucially, it also allows Tata to price the Sierra’s entry variants far more aggressively and appeal to customers who are more inclined to a lower ownership cost over performance.
In the midsize SUV space, naturally aspirated petrol engines still dominate the sales mix. The 1.5-litre petrol in the Hyundai Creta and Kia Seltos accounts for nearly 60 percent of their total sales, proving that buyers in this segment prioritise affordability and efficiency over outright performance. Tata is clearly taking a page from the Korean playbook – offering an accessible, efficient base engine and a powerful turbo option for enthusiasts.
New 1.5-litre NA petrol engine specs
Power and torque figures for the Tata 1.5 NA are expected to hover around 120hp and 140Nm, similar to those of the Creta’s 1.5 MPi engine and Maruti Grand Vitara’s 1.5 K-series unit. Tata engineers are targeting low NVH and best-in-class efficiency, with full E20 fuel compatibility built in from the start.
New 1.5-litre turbo-petrol engine specs
The 1.5-litre direct-injection turbo-petrol, meanwhile, will power higher variants of the Sierra, as well as the Harrier and Safari, and is expected to deliver around 170hp and 280Nm. Featuring variable geometry turbocharging, direct injection and advanced knock control, it’s being positioned as Tata’s flagship petrol powerplant.
Once both engines are on sale, Tata will have filled a huge void in its petrol portfolio, and the 1.5-litre will complement the 1.2-litre 3-cylinder naturally aspirated and turbo engines.
Tata trying to balance performance with efficiency
Interestingly, Tata’s approach stands in contrast to that of Mahindra, which has gone all-in on performance. The Thar, Scorpio N and XUV700 all use Mahindra’s mStallion 2.0-litre turbo-petrol, currently the most powerful petrol engine offered by an Indian manufacturer, producing up to 200hp and 380Nm, but it is thirsty. Tata, on the other hand, is attempting to balance performance with efficiency.
With the 1.5 NA engine, expect the base variant of the Sierra to be priced aggressively when it is launched later this month. Tata is banking heavily on the Sierra, which could be the ‘Nexon moment’ for the company in the hotly contested midsize SUV segment.
Rivan RS 
Viraaj Bhatnagar
Uday Singh
Suraj Viswanathan
