Technical specifications

According to Tata Group's Chairman Ratan Tata, the Nano is a 33 PS (33 hp/24 kW) car with a 623 cc rear engine and rear wheel drive, and has a fuel economy of 4.55 L/100 km (21.97 km/L, 51.7 mpg (US), 62 mpg (UK)) under city road conditions, and 3.85 L/100 km on highways ( 25.974 km/L, 61.1 mpg (US), 73.3 mpg (UK)). It is the first time a two-cylinder non-opposed petrol engine will be used in a car with a single balance shaft.[48] Tata Motors has reportedly filed 34 patents related to the innovations in the design of Nano, with powertrain accounting for over half of them.[49] The project head, Girish Wagh has been credited with being one of the brains behind Nano's design.[49][50]

Much has been made of Tata's patents pending for the Nano. Yet during a news conference at the New Delhi Auto Expo, Ratan Tata pointed out none of these is revolutionary or represents earth-shaking technology. He said most relate to rather mundane items such as the two-cylinder engine’s balance shaft, and how the gears were cut in the transmission.

Though the car has been appreciated by many sources, including Reuters due to "the way it has tweaked existing technologies to target an as-yet untapped segment of the market", yet it has been stated by the same sources that Nano is not quite "revolutionary in its technology", just low in price.[51] Moreover, technologies which are expected of the new and yet-to-be-released car include a revolutionary compressed-air fuel system[52] and an eco-friendly electric-version,[23] technologies on which Tata is reportedly already working, though no official incorporation-date for these technologies in the new car has been released.

According to Tata, the Nano complies with Bharat Stage-III and Euro-IV emission standards.[53] Ratan Tata also said, 'The car has passed the full-frontal crash and the side impact crash'.[54] Tata Nano passed the required 'homologation’ tests with Pune-based Automotive Research Association of India (ARAI).This means that the car has met all the specified criteria for roadworthiness laid out by the government including emissions or noise & vibration and can now ply on Indian roads. Tata Nano managed to score around 24 km per litre during its ‘homologation’ tests with ARAI. This makes Tata Nano the most fuel efficient car in India. Nano will be the first car in India to display the actual fuel mileage figures it recorded at ARAI’s tests on its windshield. According to ARAI it conforms to Euro IV emission standards which will come into effect in India in 2010.[55]
Rear mounted engine

The use of a rear mounted engine to help maximize interior space makes the Nano similar to the original Fiat 500, another technically innovative "people's car". A concept vehicle similar in styling to the Nano, also with rear engined layout was proposed by the UK Rover Group in the 1990s to succeed the original Mini but was not put into production.[56] The eventual new Mini was much larger and technically conservative. The independent, and now-defunct, MG Rover Group later based their Rover CityRover on the Tata Indica.

Tata is also reported to be contemplating offering a compressed air engine as an option.[