The Advent of Small Turbo Petrol

          Off late we are witnessing the advent of small capacity but highly potent internal combustion petrol engines with generous help from turbo charging. Till a few years back forced induction with the help of turbo chargers was confined to diesel engines due to their inherent lack of horsepower vis-a-vis a similar capacity petrol counterpart. Thankfully turbo charging has trickled down to small petrol engines and what we have now is engines producing as much power and torque as engines 1.5 times their capacity. What that translates to is - a one litre turbo charged engine is producing power and torque figures similar to a 1.5 litre naturally aspirated motor.

          Its an interesting development which juxtaposes the appeasement of enthusiasts and also the environment to a certain extent. Although appeasement of environment is not as much as in the case of electric engines, but as cliched as it may sound 'something is better than nothing'.

          It kind of gives you the best of both worlds. Petrolheads (or petrosapiens as I prefer to call my ilk) can satiate their hunger for exciting performance, screeching of tyres with dollops of torque and horsepower at their disposal with a heavy right foot. When driven with a lighter foot they also stretch the kilometres per litre equation akin to small capacity engines. Hence, mileage seekers' needs also checked. So, sounds like a winning formula, ain't it?

          Yes, indeed it is. But its not all as rosy as it sounds. What's disheartening is the choice of odd number of cylinders (i.e. 3) almost all manufacturers are going with and in certain cases it's without a balancer shaft. Yes most of them are very refined and at certain rpms the three cylinder thrum is almost imperceptible, but the key words here are 'certain rpms'. At rpms, other than those 'certain rpms' the typical three cylinder thrum is definitely present. I need not tell a car enthusiast worth his/her salt that - he/she will not be able to keep the engine at those imperceptible rpms all the time.

          The thing is how much ever refined you might make a three cylinder unit it can never match a four cylinder's refinement. There's a symphony which only an even numbered unit can produce and an odd numbered unit can only dream of. Distantly. You can't defy the laws of physics, can you? Yes, you can if you are Rajnikanth. Sorry for the crass joke my Tamil readers.

          So, why three cylinders instead of four? Is it impossible to produce a small one litre engine with four cylinders? Hell, No. The Kawasaki ZX-25R is proof. Ok, its a bike but with a 0.25 litre engine comprising 4 cylinders. The Santro's 1.1 litre Epsilon engine was a 4 pot unit albeit naturally aspirated.

Is it costs? Is developing and producing a small 1 litre 4 cylinder unit an expensive proposition? Well, I would leave that question for my readers who are qualified mechanical engineers to answer. 

For the manufacturers my question is - why wasn't turbo charging their existing 1.2 litre 4 cylinder naturally aspirated engines considered over developing all new 3 pot engines?

          After all the symphony produced by the orchestra of 4 cylinders is also as important as the performance of the engine. From the crescendo at the redline to the diminuendo at idle and then back again to the crescendo. Its music to the ears. Ask an automotive aficionado!