Diesel engines compared: Honda 1.5 iDtec vs Fiat 1.3 Multijet vs Renault K9K 1.5 dCi

Diesel is the flavour of the season, with Honda also now getting into the diesel-powered car market in India, with its new 1.5 litre diesel engine. The most dominant diesel engine in the Indian market today is the 1.3 litre multijet engine from Fiat, while the 1.5 litre K9K diesel from Renault-Nissan is also gaining ground.

The Fiat and Renault engines are used in multiple cars across car brands – with the Fiat engine being the most shared engine in the country also earning it the moniker of “India’s national engine”. The 1.3 litre Multijet engine from Fiat is used by at least 12 different car models belonging to Maruti, Tata, Fiat and Premier, and a variant of which is also made by General Motors.

The Renault K9K 1.5 litre diesel engine is shared by Renault, Nissan and Mahindra across seven different car models. Honda, however, has ruled out sharing its new 1.5 litre iDtec diesel engine with other carmakers and would use variants of the same within its range of upcoming cars.

Diesel engines compared: Honda 1.5 iDtec vs Fiat 1.3 Multijet vs Renault K9K 1.5 dCi

Let’s take a look at how each of these engines compares – a look at their strengths and weaknesses and what makes them unique.

Honda diesel is the most fuel efficient

All these three engines have one thing in common – they are incredibly fuel efficient, with the Honda iDtec walking away with the honors in fuel economy at 25.8 kmpl in the Honda Amaze. The 1.3 litre Multijet diesel engine has a maximum fuel efficiency 23.2 kmpl in the Maruti Ritz. The Renault-Nissan K9K does 23.08 kmpl in the Nissan Micra. Of course, fuel efficiency is governed by other factors as well, such as the weight of the car it is used in, the aerodynamics, size of turbo-charger,  gear ratios etc. Also read: Honda Amaze diesel road test and review – an amazing package

Honda 1.5 iDtec: 25.8 kmpl (in Honda Amaze)

Fiat 1.3 Multijet: 23.2 kmpl (in Maruti Ritz)

Renault-Nissan 1.5 K9K: 23.08 kmpl (in Nissan Micra)

Also read: Tata Vista D90 vs Fiat Punto 90 HP – is the copy as good? 

Fiat multijet is the most compact engine

In terms of size, the Fiat 1.3 litre multijet engine is the most compact engine of the lot, and is also the lightest with a weight of 125 Kg for the engine block alone, despite being made of cast-iron and aluminium. The Renault-Nissan K9K 1.5 diesel engine with a cast-iron base and aluminium alloy head is also fairly light. Figures from its application in Dacia vehicles show it has a service ready weight of 127 Kg, slightly more than the 1.3 multijet, but lighter than the Honda engine.

The Honda 1.5 iDtec has done a lot to shave off weight of the engine, but it still weighs 152 Kg, being an all-aluminium engine block. It is, however, larger in capacity. Honda has used thinner walls for the cylinder block and reduced the size of the water pump (when compared to the larger 1.6 iDtec it is based on) to make the engine light enough for application in small cars like the Amaze and Brio.

Fiat multijet vs Honda iDtec vs Renault-Nissan K9K technical specifications

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Which is the best engine?

Overall, although the Honda iDtec makes the most power, it doesn’t develop as much comparable torque for its size given that it has a shorter stroke, and uses a fixed geometry turbocharger in the current specifications. However, this engine has the potential to boost this power figure to around 120 bhp and torque by at least 50 Nm using a variable geometry turbo, which it may in the next-generation Honda City. The Fiat multijet churns out its lowest torque and power figures in the Premier Rio and the highest in the Fiat Linea. The Renault K9K 1.5 puts out 110PS of power (108 bhp) in the Renualt Duster and torque of 248 Nm using a variable geometry turbocharger, but with a fixed turbo it makes 85 bhp and 200 Nm in the Sunny or just 63 bhp and 160 Nm in the Nissan Micra or Mahindra Verito. Also read: Performance modifications for your diesel car

There is no clear winner here on which is the best engine of the lot. The K9K is endearing because of its simplicity, the Honda because of its precision engineering, while the 1.3 multijet is probably the most versatile of the lot. All three engines are reliable diesels in their own right.