Topic: 427lb-ft.... diesel 3-series coming.

[G35X]

6.6 litres of diesel is equivalent to 7.4 litres of gas as far as CO2 emission is concerned.   Yes, the new TDI is more efficient, but not by the ratio of fuel consumption per km simply because diesel fuel is packed with about 12 percent more hydrocarbons per volume.

[kevlar]

6.6 litres of diesel is equivalent to 7.4 litres of gas as far as CO2 emission is concerned.   Yes, the new TDI is more efficient, but not by the ratio of fuel consumption per km simply because diesel fuel is packed with about 12 percent more hydrocarbons per volume.

i am not sure where you are getting all of your figures but they don't add up.  the new clean diesels do not put out more co2 than a comparable displacement gas engine.  also it doesn't cost 5-10k more to produce a clean diesel engine.   an audi a4 2L tdi puts out 134g/km of co2 and gets 55 mpg combined 5.1l/100km.  a 1.8L tfsi puts out 164g/km and gets 39.8 mpg 7.1l/100km.   the tdi produces less co2 per km.  this is the most important issue not ratios of hydrocarbons per volume.  the bmw 330d is going to get almost 50 mpg, 152 co2 g/km, 245hp and stump pulling torque. 

[G35X]

Hydrocarbon turns into CO2 (and CO) and H2O when burned (plus H, H2 and C when too rich).  Since density of diesel is about 12% more than that of gas, a litre of diesel produces 12% more CO2 than a litre of gas when burned.
So, if we compare a 10 litres/100km gas automobile and a 7 litres/100km diesel automobile, we cannot say the diesel emits 30% less CO2.  It is more like 22% less.  Still it is good, which is due to higher thermal and mechanical efficiency of the diesel engine.

As for the cost difference let’s see the price difference between 335i and 335d…  Do we know the price of 335d?  With its sturdier construction, more complex fuel injection system, more expensive cat converters and DPF in addition to the urea container and spray system plus the amortization of years of R&D to clean it, definitely the diesel engine costs much more than the gas counterpart.  If BMW keeps the price differential around 3000 dollars, which should be the maximum marketing wise, BMW is making less money by selling the diesel model.

[kevlar]

Hydrocarbon turns into CO2 (and CO) and H2O when burned (plus H, H2 and C when too rich).  Since density of diesel is about 12% more than that of gas, a litre of diesel produces 12% more CO2 than a litre of gas when burned.
So, if we compare a 10 litres/100km gas automobile and a 7 litres/100km diesel automobile, we cannot say the diesel emits 30% less CO2.  It is more like 22% less.  Still it is good, which is due to higher thermal and mechanical efficiency of the diesel engine.

As for the cost difference let’s see the price difference between 335i and 335d…  Do we know the price of 335d?  With its sturdier construction, more complex fuel injection system, more expensive cat converters and DPF in addition to the urea container and spray system plus the amortization of years of R&D to clean it, definitely the diesel engine costs much more than the gas counterpart.  If BMW keeps the price differential around 3000 dollars, which should be the maximum marketing wise, BMW is making less money by selling the diesel model.

the price differential of a 320i and 320d in the uk is 2k pounds.  that is approx 4k dollars.  thats in a country where the diesel is widely accepted.   i agree that the differential here will be 3k or less.   the most important figure is grams of co2 emission per km.  that's why every european auto web site quotes g/km.  all of the other figures are interesting but not really that relevant.  i am hoping bmw and audi are aggressive with their pricing.  i might trade in my 3.2L avant for the 3L or 2L diesel.   by the way, the honda hybrid is almost 10k more than the base civic and the hybrid camry is 7k more than the base camry. 

[G35X]

“ …the most important figure is grams of emission per km… “ – Kevlar

Yes, I agree. That’s the law in EU.  120g/km is very tough to meet. It is equivalent to 19.3km/litre or 5.2 litres/100km.  In six years from now automakers will have to meet this CAFE, otherwise they will have to pay 95 euro penalty per gram/km/car above this number. The amount of CO2 emission is directly related to the amount of fuel burnt. No cat converter or other emission control device can reduce it.  So, automakers have to dilute the higher numbers by selling more and more zero- or near-zero-CO2 vehicles if they want to sell high-performance cars such as the 335i and M3.  Here comes the importance of EV’s and micro cars.  Fortunately BMW has the Mini EV, which I think is one of the most attractive future commuters.  Let there be many, many Mini EV's charged up with otherwise wasted off-peak electric energy so that we can enjoy driving 335i’s and M3’s on weekends.

[kevlar]

ultimately the hybrids will become clean diesel hybrids and biodiesel hybrids once battery technology improves over the next decade.