SteVTEC

Gas-hybrids add a significant amount of cost and weight, which can force a manufacturer to cut corners elsewhere in a vehicle, and can also detract from other performance aspects such as cornering and braking. A turbodiesel engine is a nice and simple, cost effective, and lightweight way to significantly improve the efficiency of a vehicle while not detracting from some of those other vehicle performance aspects, areas that a company like BMW would be very keen to avoid hurting. Especially the BMW M57 Inline-6 cylinder diesel engine is hardly clattery or unrefined either. It definitely sounds a lot different than a gas/petrol, but it doesn't sound bad.

Have not had the opportunity to sample a BMW 320d because none has ever been offered here in the U.S., but I'm guessing it's not nearly as bad as a lot of people might expect. Unpleasant sounds and NVH are very much under control with BMW's newest N20 2.0L turbo/petrol engine. It still sounds like a 4-cylinder, but BMW obviously has plenty of tricks and know-how up their sleeves. I would seriously consider a BMW 320d for my next car.

natnut

From my experience test-driving a Jaguar XF 3.0 turbodiesel, it still doesn't match the linearity and smoothness of a NA petrol engine. 2 problems from my test-drive : turbo-lag and the low-revving nature of the diesel. Not sure how a BMW turbodiesel measures up though.

Vladi

Same thing pretty much except that BMW diesel gives you a feeling that it's not running out of steam at upper revs and keeps going. It's still a lot more punchy at the bottom.

BMW diesel is the best diesel engine concept in the world so if you don't like a beemer oil burner most likely you will get disappointed with every other.

DustinV

Modern-day diesel engines can only get better. Their refinement depends on the type of high-pressure-injection-system they have and engine management.

I recall how in the late 1990s Audi/Volkswagen TDI engines were often criticized for a lack of refinement. This was because they used unit-injector technology, which had these characteristics of loud combustion / vibrations. BMW and Mercedes made use of common-rail technology, which improves refinement and reduces noise.

By now, BMW and Mercedes are on their third or fourth generation of common-rail technology and Audi/VW have also adapted common-rail for their TDI engines. These new engines are pretty good in terms of refinement, noise output etc. They're also smooth. Technology doesn't stand still. It's constantly improving.

In the end, someone opting for a diesel-powered luxury car will care more about getting the most range and best fuel consumption possible than refinement. Or, to them, the engine is refined enough. Not all luxury buyers are the same and engine refinement is a subjective opinion which some people care about and some don't.

SteVTEC

^ Yeah I now they're going crazy with the common-rail direct injection systems for diesels, with possibly over a dozen injections per combustion cycles to smooth out the combustion process and improve emissions. I know they can do multiple pre-injections, a main or possibly several main injections, and then post-injections also.

DFGeneer

I know they are improving, but they are still far, far away. Just last week I test drove a 320d. It feels horrible in terms of refinement compared to my 2JZ-GE powered IS300. And the start/stop system constantly reminds how bad actually things are. Every restart of the engine makes the whole car shake. And then there is the turbo-lag... Sorry guys, diesel = no premium feel to me.

SteVTEC

^ Try a 6-cyl.

Blackraven

^Yup

Or that M550d xDriveAWD (3.0 liter TRI-TURBO diesel engine with something 2000 bar of pressure I think). Sick indeed

spwolf

i want to drink what you are drinking :-).

Modern turbodiesels are not simple, nor they are cheap. How in the world did you come to that conclusion?

320d is, by all reports, a fine car... Engine is efficient and reasonably quick, especially compared to your NA 4cly. It is not simple though. By no means it is simple, it is in fact pretty complicated technology that is not cheap at all... they are usually around >$3k or more than comparable petrol engine.

And still, you get around 2000 rpm of usable rev range, usually between 2000 and 4000 rpm...

natnut

Not to mention, due to its complexity and additional components, a modern-day diesel engine of equivalent displacement/ power is almost always heavier than its petrol counterpart. So one could argue for diesels by way of fuel efficiency and straight-line acceleration/speed but no way does a heavy diesel engine in the nose of a car help in handling/ cornering.

IMO. a true driver's car =/= diesels

DFGeneer

Yeah, I too don't see how diesel and sport go together.
Sport (at least to me) means instant throttle response and high revving engine. Diesels are slow to react, nonlinear in response and weak at the high revs, exactly the oppsite.

bagwell

A little difference in the aroma there....unless you brew your own biodiesel from a restaurant