-
Diesel or petrol?
I can still remember when, not that long ago, diesel engines were considered smelly, dirty, noisy and underpowered lumps of metal. They were basically used in medium and heavy duty applications like buses, trucks or vans and the few cars that had them were slow and in general something to be avoided. Fast forward to 2009 and you can see them everywhere. Some cars, like the Citroën C6 or the Peugeot 407 Coupé are only sold with diesel engines.
Not only diesel cars seem to be the norm nowadays, but they have come a long way indeed from the early, and not so early, days. They have improved notably in the noise, vibrations and harshness department and they are ever increasing performance while reducing fuel consumption at the same time. Is there room for petrol engines at all these days?
I've always been a petrol defender. I've always thought that diesels were more suited to tractors and that anyone that bought a diesel was a bit greedy and not interested in cars. Certainly in some cases, like for instance people who do very high mileage, diesels do make a lot of sense and the savings are certainly noticeable. There are other cases though, in which people act like sheep. I have for instance never understood city cars with diesel engines under the bonnet. They are far more expensive than their petrol counterparts and the usually short distances driven by this sort of cars cannot compensate the price difference.
At the same time petrol engines have come a long way too. The latest technology includes direct fuel injection, turbocharging and downsizing. They have reduced fuel consumption and emissions greatly. Indisputably petrol engines are much more refined and smooth than diesels, even modern common rail units. You can try this by starting a petrol powered car and diesel powered car with the door open and then letting them idle. There's really no contest here. On the move the difference is much smaller, and here the advancements made by diesels are really clear. At high revs petrol beats diesel again, the noise made by petrol engines is much nicer.
And yet in some situations you just can't argue with diesels. In a recent 350km journey I did our BMW 118d recorded 7l/100km cruising at speeds between 160km/h and 180km/h about 90% of the trip. Even if you push hard you'll still struggle to get over 10l/100km. I have also had the opportunity recently to drive a brand new Lancia Delta T-Jet powered by a modern 1.4 litre turbocharged four cylinder engine. If you are careful with the throttle you can get relatively close to the BMW's figures, an average of 7 to 8L/100km is possible, but as soon as you start driving like an Italian numbers grow exponentially. 15L/100km aren't out of reach at all. So it doesn't look like you'll be buying a petrol for economy any time soon.
Despite all I still can't get to love diesels. I've driven one now for 1 and a half years and it's been brilliant, fast and frugal. It's not perfect though, there's still a bit of turbo lag and it isn't as refined as a good petrol motor but so far very good indeed. But I don't want it. Aside from the problems already mentioned, it makes me feel cold like if it was an appliance. When you are in your favourite mountain road enjoying the brilliant drive of your car the diesel engine is a big let down, it detracts much from the experience. I'm sure this is accentuated by the brilliant driving abilities of the little bimmer, and I wonder what would happen if the diesel was in the Delta and the petrol in the 1 series.
Then there are case in which a diesel engine simply has no place. These include cars with sporting pretensions like hot hatches and more than anywhere sportscars. Also some brands like Alfa Romeo or Jaguar, simply shouldn't offer a diesel at all, because those cars should be viewed as pure driver's cars and no driver's car should be saddled with a diesel engine because it's simply a sacrilege and there's no argument to be had here. Furthermore they have an heritage, expertise and aural pleasure that should never ignored. Of course for a bit of weekend fun petrol still reigns supreme.
However in the real world diesels do make a lot of sense, especially as soon as you are off the city and on to roads and motorways. The arguments for diesel are very strong and other than the romantic view it's difficult to make a case for an everyday petrol powered car. Heart says petrol, but head says diesel. What's it going to be?
-
It all comes down to the way you use the car.
The truth is that from a financial point of view, the Diesel is superior to the Petrol engine because of its accessible power band and the better fuel economy for a given power figure.
Many argue for the emotional qualities of the petrol engine, like the higher revving character and the sound. True, but this realistically applies only to sports cars. If someone buys a Mondeo 3.0 V6, then he is wasting his petrol over a bad chassis.
Conclusion: 80% of the population's driving style is better suited to the Diesel, but for some reason some of them choose petrol engines.
-
[quote=lightweight;906867]It all comes down to the way you use the car.
Conclusion: 80% of the population's driving style is better suited to the Diesel, but for some reason some of them choose petrol engines.[/quote]
Or, they live somewhere that diesel is, or nearly is banned....like California. in the late 1990s and early 2000s, it was almost criminal to own a diesel powered car there....not sure it is viable here yet;)
-
[quote=lightweight;906867]Many argue for the emotional qualities of the petrol engine, like the higher revving character and the sound. True, but this realistically applies only to sports cars. If someone buys a Mondeo 3.0 V6, then he is wasting his petrol over a bad chassis.[/quote]
Precisely. Say you need a family car. For the car enthusiast what should it be the ST220 or the 2.2 litre diesel?
(And I always thought the Mondeo had a very decent chasis)
-
[quote=wstander;906871]Or, they live somewhere that diesel is, or nearly is banned....like California. in the late 1990s and early 2000s, it was almost criminal to own a diesel powered car there....not sure it is viable here yet;)[/quote]
True, but since the topic states diesel or hybrid, I kind of excluded Hybrids or electric cars.
Normally Diesels in Europe serve the same purpose as Hybrids in the US. You pay a price premium when you buy the vehicle in order to be able to capitalise on its fuel economy and break even on fuel costs.
The only difference with Hybrids is that since the price premium over equivalent petrol cars is bigger than Diesel, the time needed to break even is also bigger.
Now for the REAL conclusion:
- Most Diesel and Hybrid buyers buy a new car before they break even on the price premium of their car.
- Diesel is more harmful to the environment than equivalent petrol engines (comparing same Carbon Dioxide figures)
- Diesel and Hybrids save on Carbon Dioxide emissions, but in order to be manufactured, lots of toxic materials are being used, that aren't treated in any way after the vehicle ends its life. So we are in a state where we are proud of reducing CO2 emissions, but we are blind towards toxic pollutants poisoning us and creating all-time high cancer readings.
Hmm... Seems that I widened the topic here a little bit...
-
[quote=Ferrer;906873]Precisely. Say you need a family car. For the car enthusiast what should it be the ST220 or the 2.2 litre diesel?
(And I always thought the Mondeo had a very decent chasis)[/quote]
It all boils down to someone preferences as I mentioned earlier.
I don't think that driving 300 Nm of high end Petrol torque through the front wheels offers satisfaction to the "sporty" driver when going through a corner.
On the contrary 300 Nm of low-down diesel grunt that enables you to effortlessly cruise on the Motorway with minimal fuel consumption, is a much more logical solution.
Someone of course might fancy torque steer etc (After all there are people who buy Astra OPC / VXR).
-
[quote=wstander;906871]Or, they live somewhere that diesel is, or nearly is banned....like California. in the late 1990s and early 2000s, it was almost criminal to own a diesel powered car there....not sure it is viable here yet;)[/quote]
California does it's own thing regardless of what's actually intellegent. Don't even get me started on that state.
I'd say that diesel vspetrol really depends on the application. I'm a huge diesel fan, but even I think that they should be kept out of sports cars. Sure, diesel race cars have been dominating some arenas, but a sports car should be about the driving experience and for the reasons you mentioned diesels can fall short in a little sporty car.
However there are a lot of areas where diesels can be superior and I think continuing to develop diesel technology for more applications is a good thing. Some day diesels may match petrol in areas where today they seem like sacrilege.
-
i'm a big fan of diesel 4X4's, hilux, particularly the nissan patrol utes and the like.
there is precisely zero chance of me having diesel in any road car i own at the moment however. i will start distilling my own ethanol blend haha.
would consider it when the time comes round for a family car, but it is unlikely.
-
I love the idea of diesels and I'm toying with the idea of getting a really cheap diesel project car..but I've never actually driven a diesel I liked. Dad has a new turbo diesel Ranger and sure it uses no fuel at all, but the powerband feels like it is about 100rpm wide.
-
i need to drive some diesel's see waht its like! i'm very interested in them. all that torque and low rpms!
-
Diesel cars are more fuel-efficient than petrol-driven ones - burning a litre of diesel creates more CO2 than burning a litre of petrol, but the engine efficiency just about makes up for that. However, diesel will create more dirty emissions such as nitrogen oxides and particulates that can affect health. If you are considering buying a diesel car, choose one with a diesel particulate filter,as this will reduce these emissions.
-
remember that the lag of a diesel is also due to the "combustion" process. Using the same turbo and same specs and all, a petrol car will still have less lag than a diesel one.
-
[quote=LeonOfTheDead;907057]remember that the lag of a diesel is also due to the "combustion" process. Using the same turbo and same specs and all, a petrol car will still have less lag than a diesel one.[/quote]
Not sure myself, but given that the Diesel has a very high compression ratio (Maybe 20:1 and upwards), I would expect that the Diesel wouldn't be laggy
-
[quote=lightweight;907058]Not sure myself, but given that the Diesel has a very high compression ratio (Maybe 20:1 and upwards), I would expect that the Diesel wouldn't be laggy[/quote]
The process of vaporizing and mixing the fuel with the air takes more time than in a petrol car, due to the viscosity and density of the diesel. the high compression ratio of a diesel is also lower than what it used to be, while petrol engines are adopting higher ones than in the past.
-
[quote=lightweight;907058]Not sure myself, but given that the Diesel has a very high compression ratio (Maybe 20:1 and upwards), I would expect that the Diesel wouldn't be laggy[/quote]
I cannot quite get into the technicalities of it, like Damiano can, but comparing the Delta and the BMW, the bimmer has far more lag despite a 600cc advantage over the petrol engine.