Music to homecoming Chennaiites: the sound of the Chennai auto

Tut, tut, trrrrrr…sometimes they even have a name for it: Burr Beat. It’s like hip-hop, evocative music, rhythm—hip and cool. It’s the sound of the Chennai auto

There are more than 1 lakh autos in Chennai, and the auto sound is as much part of the city as the brutal bargaining the Chennai auto driver subjects you to

No, it’s not the autorickshaw makers who give the Chennai auto its distinct sound; they in fact ensure it’s the normal, restrained sound that vehicles make

But many auto drivers, as soon as they take delivery of their three-wheeler, rush to the workshops dotting Chintadripet for an upgrade

So, what do the street-corner gearheads of the narrow bylanes of Chintadripet know that the finest engineers employed by reputable OEMs don’t?

“The carburetor and the silencer need to be tuned,” says Murthy, an auto driver in Kilpauk. Tuning the silencer often involves removing the internals of the device

He trusts the Chintadripet mechanic to ensure that his newly minted auto provides a mileage of at least 28 km per litre. His trust is based on good engineering principles

The engine burns fuel and produces a pressure pulse that makes the auto run. Unburned gas is let out through a pipe, which is designed to not have obstructions

If there is an obstruction or the passage is not smooth, then the engine has to work harder to pump the exhaust gas out. That means more fuel is burned

However, noise pollution norms dictate that exhaust gas is slowed down and its energy dissipated, reducing noise. That means placing an obstruction in the pipe

This leads to a fuel-efficiency penalty. It’s a trade-off we have come to accept. Burn slightly more fuel but keep the noise down

For auto drivers eking out a living, the choice is clear: removing the silencer would save fuel. The few rupees they save can make a big difference for them

Ramesh, another auto owner, gives a back-of-the-envelope calculation: Rs 300 of petrol will run the auto for some 80 km, giving the driver Rs 1,000 on a good day

Removing the silencer would give him an additional Rs 50. And that’s well worth it for an auto driver living on the margins. It could pay for a meal

But for Murthy and others, that’s just a perk. The real benefit is the sound. It gives them that feeling of riding a mean machine

Murthy insists that not only is the pickup greater – an engine that faces no backpressure can ramp up power quickly – but the ride is smoother too

Murthy says the sound is custom-made. The typical metallic, loud sound is one thing. But the burr beat is more sophisticated, and sheer music, he believes.

Ramesh says fewer auto drivers now are going for silencer removal, as they get regular white-collar customers who wouldn’t want the loud sound. Neither does he