A diesel engine in a Maruti SX4 is big news! In the small saloon segment, the SX4 has been neck to neck with rivals like the Hyundai Verna, VW Vento and Ford Fiesta even without a diesel engine. As diesel engines account for some 60 per cent of sales in this segment, a new diesel plant will give their sales a big boost. I was a bit skeptical that a small 1,248 cc diesel engine could adequately propel a muscular 1,200 kg saloon, especially if it was to be compared with the 1,600 cc 105 HP petrol engine that powers the sister Maruti SX4 that is one seriously peppy car. When I slotted it into gear however I was unprepared for its responsiveness. Looking more closely at the specifications I found that although the peak HP was only 90 as compared to 105 for its petrol sibling, the little diesel had much higher torque at 200 NM as compared to 145 for the petrol engine and at a low 1750 rpm. The result was surging power, as soon as one touched the accelerator. Most people do not understand that peak HP is only notional because no one ever takes an engine to its top engine speed. On the roads it is the torque in the normal driving range of between 1,500 to 3,000 rpm that determines how a car accelerates.
Suzuki, like all Japanese automakers, was slow to shift from petrol to diesel engines that were earlier much more polluting, noisy and sluggish than petrol plants. The Italian automaker Fiat pioneered the high pressure ‘common rail’ technology that revolutionised diesel engines.
This technology increased power by roughly 30 per cent and was also much quieter and less polluting than the old smokers. Good power at low engine speeds also results in fewer gear changes and big savings in fuel consumption. According to ARAI the petrol SX4 gives good fuel consumption of over 15 kmpl under test conditions but the new diesel gives 21.4.
It was not therefore surprising that Suzuki turned to Fiat when they saw the rapidly rising popularity of diesel cars in India and picked a small 1,248 cc gem that Fiat had first used in a small Alfa Romeo model a decade ago. It is now seen in the Maruti Swift, Dzire and Ritz models. It is a remarkable little turbocharged engine that offers excellent performance and relatively high top engine speeds of up to 5,000 rpm allowing very responsive power delivery from low to high engine speeds. This engine now has a variable geometry super turbo DDIS turbocharger for even better performance. The new variant in the SX4 also boasts of being the first OBT compliant engine. This ‘On Board Diagnostics’ has a host of microchips monitoring all engine functions to make silent adjustments to ensure optimum performance at all times. It is amazing what micro chips can do. Behind the wheel the new car was a pleasure to drive as it effortlessly accelerated from idling speeds and could effortlessly go up to high speeds of over 160 kmph (the top speed that traffic would allow) without any jerks or turbo lag. The petrol SX4 is an excellent saloon and the diesel engine will naturally cost a bit more than its petrol siblings at `7.74 lakh to `8.62 lakh.

The writer is an automotive analyst and the former editor of an auto magazine