Quote:
Originally Posted by aesthetect
those are the theoretical efficiencies of each cycle and there are many variables involved in calculation of those values, the main factor being compression ratio which is obviously much easier to push the limits with in the diesel cycle. also those are just peak efficiency values, location and distribution of those with respect to drive cycle is what will determine your actual mpg performance. the benefits in efficiency and fuel economy are at least significant, not to mention a torque value in the 335d that provides just the kind of grunt that makes a sports car fun to drive around town, and i dont know about you but thats where i tend to spend my time. because i am an environmental nerd i cant help but love the diesel (also because i effin love the torque), but i have never driven a sporty diesel car, only trucks, so really as far as driving experience im talking out of mere speculation.. yes diesels rev more slowly and favor lower rpms but couldnt this be geared to give the driver a sporty experience? i really would like to know.. the 335d has gotten great reviews thus far. do they really have the sluggish feeling of a typical truck diesel?
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Of course the values represent theoretical max efficiency.
A diesel delivers the torque much differently from a gasoline engine. The peak value is around 2000 rpm, then it decreases which makes the acceleration decreasing or at most being constant until 4500 rpm.
Of course modern diesel are really nice to drive thanks to the torque, especially in a SUV or a big sedan, but for me it just doesn't represent what I expect from a sportcar.
The 335d is certainly the best diesel, but it costs 3100 euros (in france, for same base equipment except that 335d has auto trans standard) more than a 335i, 6.1 sec from 0 to 100 km/h VS 5.5 sec for 335i, and 31mpg VS 25mpg for 335i.
So, you need to drive it a lot to overcome the 3100eur price gap with the fuel efficiency. And you still have a slower car, you miss the typical BMW gasoline inline 6 sound and have a car which vibrates at idle.
Ok, the sound is not that bad and the torque sensations are funs but you miss something, and if you really seek fuel efficiency, a 330d is much much better for just 50hp less.
Of course in France, Germany and other country of Europe, it makes sense because Diesel is 25% cheaper because of taxes, but in US, I don't really see the point of buying a sport car like the E92 in the 335d version.
I often drive a 530d and a E46 M3 so I can quite compare the sensation (even if the M3 is much powerful), and I ve been driving mostly diesel since I can drive (I haven't got the choice), but my next car won't be a diesel for sure.
btw, automobile forums in France often turns in fights between pro-diesel and anti-diesel, especially when it comes to 335i/335d, it's just funny.