The Tata Zest and the Maruti Suzuki Swift Dzire use the exact same Fiat engine. It’s the 1.3-litre, four-cylinder, turbodiesel that can also be found in some GM vehicles in India. This engine is available in India in two states of tune – 74bhp and 89bhp. Maruti has decided to go for the fixed geometry turbo-equipped 74bhp version mated to a 5-speed gearbox. The Zest meanwhile uses the VGT or variable geometry turbo 89bhp variant, again with a 5-speed ‘box.
A VGT, in theory, is supposed to cut turbo lag and one can feel that linearity in power delivery on the Tata from the word go, especially in comparison to the Dzire at lower revs. Sadly, that’s where the good news for the Zest ends.
Maruti somehow manages to extract the best from this engine. The turbo lag apart, the Dzire has better throttle response, the engine revs higher, and it makes much better use of its 190Nm of peak torque output compared to the 200Nm the Zest puts out.
Now before we jump into the performance figures, let’s talk AMT.
The two cars use different gearboxes but the AMT setup – which uses separate ECU to work those hydraulic actuators and time their inputs – are from the same supplier. But, the Dzire’s unit is more intuitive and seamless in its operation. It still has that typical AMT shift lag, but the lag is only as much as it would be in a manual driven by a regular guy, and not by someone chasing the quickest 0-100kmph times. Having said that the AMT equipped Dzire diesel is only 0.3 seconds off the manual Dzire diesel times; the latter was of course, driven to extract the quickest possible acceleration times.
The Zest’s AMT behaves like one of those laid-back taxi guys chasing fuel economy. It is slower reacting than the Maruti’s. It has duller throttle response. And though it comes with a Sport mode, which gives its AMT a much-needed spring in its step, it never feels as well calibrated and smooth as the Maruti’s. Worst of all, the Zest’s AMT doesn’t come with a ‘creep’ function, a must really for any automatic. The Dzire gets it.
Both AMT ‘boxes also come with manual override. In Dzire’s case, the engine doesn’t upshift on its own and will continue to bang off the limiter if the driver chooses not to upshift; a great thing for those who like to drive enthusiastically around switchbacks. The Zest’s ‘box does hold onto revs a little longer in manual mode, but upshifts near 4,000rpm in any case. To us, this defeats the purpose of having a manual mode for an AMT.
Now, the performance figures. The Dzire hits 100kmph in 13.7 seconds while the Zest takes 15.1 seconds. Blame it on Tata’s excess weight or the way the engine is setup but one can’t feel the 15 extra horses on the Zest. It’s the same story in drivability times. The Maruti completes the 20-80kmph run in a quick 8.6 seconds while the Zest takes 10.4 seconds to complete the same run.
It’s only in the 40-100kmph run – a test that simulates getting back to cruising speeds on the highways – that the two run neck-to-neck. In fact, the Dzire with a time of 11.4 seconds is 0.1 seconds off the Zest’s pace here. The more powerful but slower responding Tata unfortunately is also less efficient: The Zest returned an overall fuel economy figure of 13.2kmpl while the Dzire’s figure was slightly higher at 14.2kmpl.