A Look At What Doesn’t Meet The Eye

Technology Comparison January 2019 Hyundai Santro Tata Tiago Cooling NVH
A Look At What Doesn’t Meet The Eye

Hyundai recently launched the next generation Santro compact hatchback in India. The car was reintroduced in the market with ample flair and panache. The new Santro essentially fills in the void that was left behind after Hyundai discontinued the i10. The newest offering now faces heavy competition from the likes of the Maruti Suzuki Celerio, Wagon R and the Tata Tiago. We got a hold of the manual variant of the Tata Tiago and pitted it against that of the Hyundai Santro. To take a peek at what doesn’t meet the eye, we evaluated the NVH, air-conditioning and interior space performance of both these hatchbacks. Here is what we found.

COOLING PERFORMANCE

Indian climatic conditions can be extreme for most part; we rely heavily on the air-conditioning units in our vehicles to bring ambient temperatures to comfortable limits. With that in mind, we set out to evaluate which of the two hatches cool their respective cabins quicker. For this test we took temperature readings from an HTC Instruments MT-04 laser guided infrared thermometer with an accuracy of ± 2 % of readings. The readings were taken in four seating zones of the respective cabins of the Santro and Tiago at 12 pm IST after the vehicles had been in the sun for 30 min.

Seating space and comfort for front passengers is more on the Tiago

To begin with, the average temperature inside the cabin of the Hyundai Santro was 33.5 °C, while that of the Tata Tiago was 34.5 °C. Within two min of the air-conditioning units running at maximum blower speed with the cooling set at maximum, we observed that the average temperature inside the cabin of the Hyundai Santro fell by around 8.57 °C, while in the Tiago it fell by 8.22 °C. It was also noticed that after two min had elapsed, the cooling performance in the rear was slightly better in the Santro than that of the Tata Tiago. While average temperatures in the rear section of the Santro fell by 7.8 °C, the average temperature in the rear section of the Tiago only fell by 5.7 °C. The major difference in better cooling performance of the rear bench in the Hyundai Santro can be attributed to the addition of rear air-conditioning vents, a feature not being offered on the Tata Tiago.

Within 10 min of running the air-conditioning units in both vehicles, it was noticed that the average temperature inside the cabin of the Santro stood at 17.9 °C, while the average temperature inside the cabin of the Tiago stood at 19.4 °C. With the cabin temperatures in that of the Hyundai Santro cooler than that of the Tata Tiago by nearly 1.5 °C we noticed that the addition of rear air-conditioning vents played a big role in improving the air-conditioning performance of the Santro. Average temperatures in the rear section of the Santro were 2.5 °C cooler than that of the Tiago.

After 16 min had elapsed, it was noted that the average temperatures in the front section of the Hyundai Santro was 0.9 °C cooler than that of the Tiago. The average temperature inside the cabin of the Santro after 16 min had elapsed was 1.45 °C cooler than that of the Tata Tiago. After taking recordings after two min in each cabin, our tests culminated in 20 min with the Tata Tiago recording an average cabin temperature of 15.52 °C and the Hyundai Santro recording an average cabin temperature of 13.72 °C. During the entire process, we noted that the Santro’s cooling is quicker with cabin temperatures falling at an average of 0.9925 °C/min. The average temperature drop over a 20 min span in the Tata Tiago was recorded as 0.9512 °C.

With these results we can safely conclude that the air-conditioning performance in the Santro is mildly better than that of the Tiago due to a more effective distribution of cool air throughout the cabin.

The lack of rear air conditioning vents in the Tata Tiago indicate a more gradual decline in cabin temperature for the rear. The Santro however offers even cooling across the cabin

NVH PERFORMANCE

In order to analyse the NVH levels inside the cabin of the Hyundai Santro and Tata Tiago, we used a Robert Bosch Engineering and Business Solutions application. Using this application, we generated a colour spectrogram, which depicts a spectrum of sound pressure level measured in dB, displayed as segments over time. The test, also known as FFT (Fast Fourier Transform) Vs Time uses colour bands according to the intensity of noise inside the car’s cabin. In this test we have visualised the multiple frequency components of noise recorded in both the cabins of the Hyundai Santro and the Tata Tiago.

The first and most distinct difference, which can be noted between the results of NVH performance in both cabins, is that the sound insulation in the cabin of the Tata Tiago is slightly better than that of the Hyundai Santro. The basis of the test was to conduct it in real world conditions; for this we parked both vehicles at an isolated location and conducted the test simultaneously. In the cabin of the Hyundai Santro, we recorded a sound intensity ranging from higher than 55 dB but well under 2.51 kHz. For the Hyundai Santro, we recorded a maximum of 25 dB ranging up to the 5.01 kHz mark. The results of the Tata Tiago were slightly better.

The Tata Tiago’s NVH performance was a little more encouraging. The Sound Level Meter (SLM) indicated a slightly quieter cabin and the overall results of our FFT Vs Time tests resulted in the same indication. In the Tata Tiago, we recorded a sound level of above 55 dB, but only in a small range of the frequency spectrum. In the Santro, the sound intensity above 40 dB ranges well above the 1.01 kHz frequency spectrum. In the cabin of the Tata Tiago, we did not record a sound intensity of 25 dB above 2.51 kHz. The results concluded that Tata Tiago has a quieter cabin when compared with the NVH performance of the Hyundai Santro.

SLM recordings indicate the cabin of the Tata Tiago is better at insulating against ambient noises, this is in contrast with that of the Hyundai Santro where in during our FFT Vs Time test, the instrument recorded a higher dB level in a broader frequency spectrum

ENGINES & POWERTRAIN

The Tata Tiago comes powered by a 1,199 cc, three cylinder, petrol engine that produces roughly 83 hp at 6,000 rpm and a peak torque of 114 Nm @ 3,500 rpm. The petrol engine is mated to a 5-speed manual transmission and the same transmission is also available with an AMT option. The Hyundai Santro, on the other hand, is being offered with a 1,086 cc, four cylinder, petrol engine. The motor is capable of producing 68 hp at 5,500 rpm and a peak torque of 99 Nm at 4,500 rpm. Hyundai has mated the petrol engine to a 5-speed manual transmission, which has also been offered with an AMT option.

Being a four cylinder engine, the Hyundai Santro offers a smoother ride but the Tata Tiago has been rated for a higher power and torque output. The AMT units on the Santro and the Tiago are also quite different in terms of technology. While the unit on the Santro features electronic motors for actuation of gears, the Magneti Marelli unit on the Tata Tiago uses hydraulic actuation of gears. Both are controlled by a separate TCU but owing to an electronic motor actuation, the gear shifts on the Santro AMT are conceptually smoother.

The Santro has a smoother petrol engine, but the Tiago has a more powerful unit

ROUND-UP

Both Hyundai Santro and Tata Tiago are versatile and competitive offerings with unique USPs of their own. We found that the Santro was a little easier to drive and in our tests fared well. The air-conditioning on the Santro was also better than the Tiago primarily due to better distribution of the cooled air. It was also noted that the Tiago’s noise dampening was better by a fair margin, in contrast with that of the Santro. While measuring interior dimensions we also observed that the Tiago has more interior space but the Santro’s boot was a little more cavernous. Head room for rear seat occupants was found to be more on the Santro, but the Tiago had better head room on the front seats. This is primarily due to the adjustable seat height option, which is not being offered on the Santro.

TEXT & PHOTO: Joshua David Luther