[mkoesel]

Originally Posted by Radiation Joe

I believe the cost of a high performance diesel is probably close to the cost of a limited production engine like the S65. So apples to apples is probably a wash on price.

I disagree that effective cost is the same simply because sales numbers will not be the same. Also, total sales of non-diesel M3 will likely be effected (just how would be up to BMW to figure out). At best, you could say that you could increase the asking price on all M3 to account for the development of the second motor. This of course, means shrinking the total audience because you will price the car out of the range of some who would otherwise buy, and they will likely seek a competitors car with a lower price instead (such as C63).

I think your estimates for performance trade-offs are close on power and pretty far off on efficiency. 80% of the S65s power or 330 hp sounds right, but probably 60% better mileage or 32 on the the highway considering fat, sticky tires.

Better highway mileage, sure, but I was just taking a stab at overall efficiency gains. My assumption is that an M3 diesel will be driven hard just as a gasoline model will. In that case, the efficiency advantage of the diesel shrinks.

The killer to an M-type of car would be the additional weight that comes with a diesel. Note that the curb weight of a 335d is about 200 lbs more than the 335i.

But an M3 weighs about that much more than a 335i too. Now, that is obviously due in large part to the M3 specific parts that would be put on the diesel M3 as well. But my assumption is that an N55 and N57 should weigh about the same. I don't have an explanation for why the 335d outweighs a 335i by so much. Could some of it be difference in content? Again, I really don't see why a modern I6 diesel should weigh more than a comparable I6 gasoline motor.

Oh, and yes, I know the M3 has a V8, but the next generation one won't so the I6 vs. I6 comparison makes sense for this forward-looking discussion.