[GTO]

The question is : Have petrols finally caught up with diesels? Its a known fact that diesel technology far outpaced that of petrol in the last decade. Common-rail diesels gave gasoline a run for its money. More power, more efficiency, way superior driveability and lesser emissions. CRDi technology is key to mass acceptance of diesels, including in small cars, and has changed the way people look at oil burners.

The new direct injection petrols are an absolute blast. Case in point : VWs 1.8 FSI & the BMW 750Li. They make their torque so low down the revv band that driveability is diesel like, the BMW making a substantial part of its 600 NM of torque starting from 1700 rpms! I was astonished at the mammoth torque of the 750. Get this, the 750's torque is identical (@ 600 NM) to its diesel sibling.

[vipul_singh]

Not having driven one, I cannot really comment on the latest GDI/TSI petrols.

However, I can foresee some of the advantages of diesels being eroded as emission norms become more strict. For instance, in order to meet Euro-V stardards, car makers are having to resort to technologies such as Diesel Particulate Filters, which are prone to failure and require adoption of a certain driving style to ensure its working. This reduces the attractiveness of a diesel motor vis-a-vis petrols which are more fit-and-forget from the user perspective.

So on one hand petrols are catching up with diesels in terms of drivability while on the other, diesels would need to up their game if they are to remain user friendly and therefore, relevant.

[sgiitk]

While I am all for DI motors, I am ambivalent about the Turbos. A turbo while giving better performance and economy does tend to compromise on the linear power delivery. Furthermore, howsoever good the dreaded turbo lag is there. Nothing at the moment matches the smoothness and linear power delivery of a normally aspirated petrol, esp. if it has more than 4 cylinders.

I cannot agree more with GTO that in the past couple of decades Diesels have progressed phenomenally from the old unreliable smelly, noisy animals. No small credit to the Multijet technology from FIAT!

[vipul_singh]

The gurus can clarify more on this topic, but I believe the reason why FSI/DI engines are coming more and more with turbos is due to something known as the 'downsizing concept'. I have read about this in several books.

Basically, FSI technology is capable of packing both economy and power in the same engine (due to the stratified charge concept). To enhance economy at part-loads, engineers equip the car with a small turbo and reduce the cubic-capacity of the engine. That way, when the user demands less power, the engine's small dimensions maximize the economy (lesser rotating mass, etc.)

And when full power is needed, the same engine can produce copious amounts due to the turbo.

But I agree that nothing quite feels like a normally-aspirated engine.

[sushanthr77]

Originally Posted by GTO

The new direct injection petrols are an absolute blast. Case in point : VWs 1.8 FSI & the BMW 750Li. They make their torque so low down the revv band that driveability is diesel like, the BMW making a substantial part of its 600 NM of torque starting from 1700 rpms! I was astonished at the mammoth torque of the 750. Get this, the 750's torque is identical (@ 600 NM) to its diesel sibling.

Just to further substantiate , the new Fiat developed 1.8 GDI, under twin-turbo combination, makes about 265bhp and 350Nm@1400rpm!

Talk about diesel drive-ability!