Q. Will there be more noise due to 3 cylinders in petrol version of Nexon

Indian automobile manufacturers these days are increasingly focusing on making cars with 3 cylinder engines. There is a very rampant misconception among the people that 3 cylinder engines are inferior to 4 cylinder engines. Hence it is strongly believed that they are only suited for entry-level budget cars. However, the reality is the stark opposite. 3 cylinder engines have different functionality in comparison to 4 cylinder engines but are in no ways outright inferior. Optimized for Fuel EfficiencyThis is the most sought after plus point from the perspective of a consumer. A 3 cylinder engine is much more fuel efficient compared to a 4 cylinder engine of the same size. This is because of two primary factors, reduced frictional losses and lighter weight. Since there is one cylinder less, the frictional losses caused by metal surfaces coming in contact within the engine block is lesser. This basically translates to more force production for lesser fuel. Adding to that, due to the absence of one cylinder, the engine block is much lighter. Even the crankshaft constructed to hold the pistons is lighter. Basically, there is a good amount of overall weight savings. Both of these factors combined give 3 cylinder engines an upper hand in terms of fuel efficiency.

It is not that 3 cylinder engines are noisier, the difference in the sound occurs due to a different firing orders than a 4 cylinder engine.Traditionally, a balanced 4 cylinder engine will fire one of the cylinders after every 90degree rotation of the crankshaft. So, for one complete 360 rotation of the crank, all 4 cylinders have fired once. However, in a 3 cylinder engine the cylinders will fire after every 120degree rotation of crank (120x3=360)If you are talking about reliability then almost no, they are not less reliable than 4 cylinder. 

No, there is not a lot of noise but you will feel a little bit of vibrations in initial gears. Diesel is definitely more powerful than the petrol one. But petrol is not bad either.