Originally Posted by needforspeed
The N54 engine in the 335i is all aluminium (like the older e46 330i engine) because BMW didn't feel that the newer al/mg engines would be strong enough for turbocharging.
However, I think they went back to the older all Al engine due to issues they were unable to resolve with the Al/Mg alloy engine. The reason I say that is because I do not buy the comment that says it would not be strong enough.
Ferrari use a Al/Mg alloy block for their 600 hp engines in the 599 GTB, so why can that engine handle it and not the BMW.
I think one reason is that Ferrari inspects and tests each block as they are made verses BMW mass productions. So maybe it was becoming too costly for BMW to deal with the Al/Mg engines. It is a shame since the Al/Mg would give us a lighter car and cooler engine.