[Amrit@wheels]

Wonderful review Karan! Also, I completely agree with your suggestion, buy diesels till you can!

[n:CorE]

At the outset, we enthusiasts might think that the demonisation of diesel cars in modern times is unjustifiable. The issue is more nuanced than that. Allow me to explain.

As highlighted by Karan (& very cleverly by BMW on their brochure), the CO2 emissions from the diesel-powered car are indeed lesser vis-a-vis the petrol engine. Agreed. But this paints only half of the picture.

Heating air in an engine produces nitrogen oxides (NOₓ), including the toxic nitrogen dioxide (NO₂), the greenhouse gas nitrous oxide (N₂O), and nitric oxide (NO), which reacts with oxygen to form NO₂. A well-designed catalytic converter at the back will still yield 30% less NOₓ emissions in a petrol engine than in a diesel motor.

Next is the issue of Particulate matter (PM) that diesel engines produce, a known carcinogen. Prolonged exposure to this can also cause respiratory problems.

Modern diesel engines like the B57 in this X7 must go to extra lengths to regulate the NOₓ and PM emissions. Apart from the catalytic converter, it is equipped with a DPF and an AdBlue System, which requires the regular addition of a urea-based mixture. After all this, one can say that both petrol and diesel engines produce similar emissions.

We all on this forum have heard of what happens when DPF systems get clogged after a few years of use (ironically, due to the lack of use). This, and the AdBlue, are extra things to consider regarding maintenance and upkeep. Petrol engines do not need this much after-treatment.

We find primarily old, "dirty" diesel engines prying around on the roads. So, we cannot exonerate all diesel cars as being more punchy and fuel-efficient while having lesser overall emissions (not just CO₂).

In summary, I am delighted that we live in a time when we have these modern diesel engines. This engine is one of the exceptions, but it is not the norm. More manufacturers will continue to develop new diesel engines, albeit in different packages—smaller displacements, in tandem with a hybrid system (like the X7 or GLS400d), etc.

I would still advise against buying a modern diesel if your running is low. It will just add to your woes in the long run. Well-maintained modern diesel engines can now be considered as polluting as their petrol counterparts—not better, but just about the same. And that in itself is the marvel here.

[avira_tk]

The verbal gymnastics to demonise diesel is just a reaction to revenue losses, a diesel car will pay less taxes because of its efficiency, even if prices were equal, roughly 30% better without a sweat, regardless of load. The diesel is for long distance, unless you strictly potter around town, get it while you can, if you can afford it of course. India is getting some awesome expressways in the years ahead, long distance driving is much better when you don't have to worry about refueling.

Originally Posted by n:CorE

At the outset, we enthusiasts might think that the demonisation of diesel cars in modern times is unjustifiable. The issue is more nuanced than that. Allow me to explain.
...
Heating air in an engine produces nitrogen oxides (NOₓ), including the toxic nitrogen dioxide (NO₂), the greenhouse gas nitrous oxide (N₂O), and nitric oxide (NO), which reacts with oxygen to form NO₂. A well-designed catalytic converter at the back will still yield 30% less NOₓ emissions in a petrol engine than in a diesel motor.

Next is the issue of Particulate matter (PM) that diesel engines produce, a known carcinogen. Prolonged exposure to this can also cause respiratory problems.

I would still advise against buying a modern diesel if your running is low. It will just add to your woes in the long run. Well-maintained modern diesel engines can now be considered as polluting as their petrol counterparts—not better, but just about the same. And that in itself is the marvel here.

The hysteria we are subject to is CO2 emissions, diesels have lower values and there is no nuance in that. Nox gasses are part and parcel of combustion, with a catalytic converter, that is reduced, then dpf which adds complications, takes care of particulate matter. PM is primarily generated by construction and coal, not diesel alone, private usage contribution is just a fraction of it.

The old diesels aren't polluting as much, they have efficiency and run without issues for twice as much as their petrol alternative. Is the comparison is with petrols running on 95 Ron or higher? I'm pretty sure that majority of petrol cars aren't running on it, as even luxury car owners are filling up with regular petrol, what with ethanol blending and it's inevitable engine damage.

The petrol 40i isn't going to be as efficient in any way, with passengers and luggage, the diesel will have the same efficiency as the tested numbers or even better. The petrol pollutes more than it's tested emissions, but CO2 suddenly, is irrelevant. The ethanol blending is proof of idiotic, shortsighted, vote bank politics, the ecological damage of sugarcane farming is well documented, but that's for another thread.

[Karjun]

Well, I present to dear team-bhpians and guests, my family’s latest acquisition, the mighty BMW X7 40d.
We wanted a larger SUV for a while for our family road trips and the X7 was seemed a better choice to the GLS. Having the 2023 Q7 in the garage I realised the 3rd row had to usable at least by teenagers unlike the cramped 3rd row in the Q7. Our local dealer in Cochin isn’t the best at all in terms of service or customer relations or the purchase process, but since a Tanzanite blue car didn’t seem to be available anywhere else in south India, we decided to proceed with them.

After owning the car for 3 months and 5k kms I’ll share my experience so far.
Firstly the car on paper is just a few inches/cm wider than the Q7 or a GLS but the X7 feels larger since it’s pretty much a big box from the A pillar and back. But the boxy shape gives the car great presence on the road and sitting in the car, the view out with the beautifully shaped hood gives a commanding feel on the road. The width also means stepping out of the car is bit hard as you really have to stretch your legs to avoid your trousers rubbing the sills which may be covered in road grime, to avoid this it’s best to manually lower the car before exiting to make things easier especially for parents and older passengers. The intricate details on the rear lights are a nice detail. And the massive exhaust’s on the M-sport bumpers look great. The split headlines are controversial but grow on you over time.

On to the interior, the build quality is a usual BMW affair excellent fit and finish and the car is loaded to the gills with tech, Gesture control, Digital key and ADAS etc too much for me to through here. The front seats are extremely adjustable and the rear bucket seats are comfy for long distances and the individual sunroof is unique and makes it a lot airy. The third row is pretty decent and having space to stretch your legs between the rear seats helps massively. The 5 zone climate control is a great feature but I have to say the Air conditioning system is underpowered for the massive cabin especially on sunny days, I got cooling film installed on all glass panels on the to reduce heat which improves cooling but the A/C on my Innova seems to do a better job of cooling the cabin quickly, which is disappointing for a car north of 1.5 crores, hoping it’s a simple defect that can be fixed during service. The screen controls everything including climate control which is a real headache as you have to take your eyes off the road for a couple seconds as the fan speed settings are two clicks away. The CarPlay on the screen looks mega as it’s extremely wide and looks mega.

On to the driving, on roads the car is supremely comfortable, you definitely would not tell it’s running 21 inch wheels. Once you pick up speed the smaller imperfections are ironed out beautifully, it’s only the larger potholes that give a thump and unsettle the ride. The engine is butter smooth for a diesel and almost similar to a petrol in terms of NVH. The 700Nm of torque is the piece de resistance of the drivetrain. Maintaining triple digit speeds on highways seem effortless and overtaking is a breeze with the mountain of torque, never having to rev the engine, ensuring the family never realise the speeds I’m doing��. I seriously doubt diesels can get better than this. On braking from higher speeds (fairly smoothly) the car does pitch foward a tad bit but I guess it’s to be expected of a 2+ tonne behemoth of an SUV. The car returns 7-8kmpl on mixed driving conditions, I’m sure i can squeeze out 9 or maybe even 10 on my upcoming Cochin-Banglore drive. Although I did expect more since the dealership claim 14-15. The car does have coasting feature which charges up the 48v battery that fills in torque to improve efficiency.

Overall a great car especially the diesel if your commute involves long journeys as the range and efficiency are way better than its petrol sibling.