Quote:
Originally Posted by quality_sound
Iron blocks leave you all kinds of room for improvements. But, and I'm guessing here, it has to do with packaging. If they're using really thin walls an aluminum block wouldn't last long.
|
The BMW motor has an 84mm bore with what I am guessing is a 91mm bore center just like BMW's I6 engines. The Audi engine has a slightly smaller bore at 82.5mm but only 88mm bore spacing. So the Audi definitely has less matterial between the cylinders. However, VAG has other engines with similar amount of material between the cylinders such as the 4.2L V8 with 90mm bore spacing and 84.5mm bore, yet the block is aluminum. I believe this goes for the 4.2L V8 with turbochargers as well (C5 RS6).
I am just surprised that in an era where weight is so carefully managed that Audi is still using an iron block. As I said, I can't think of another iron block in a mainstream passenger car engine today, though I am recalling now that the VAG narrow angle VR6 engines are also iron. However, just for example, Ford, Hyundai, Honda, GM, and now BMW are all using aluminum blocks for their four cylinder turbocharged engines. VAG's 3L supercharged V6 uses an aluminum block as well, and I would be very surprised if their new 4L V8 turbo does not do the same.
Quote:
|
Good motor? Yes. Comparable to the VWAG 2.0T? I wouldn't put it up there with it. Maybe a notch below.
|
I'd call it a wash, myself, at least on paper. Each has its pros and cons. I just hope BMW has solved their HPFP issues.