[trixdout]

I've searched and searched and searched, maybe not hard enough.

I understand the n54 crank is forged.

My question is, are the specs and measurements of the n55 crank the same as the n54 crank? Meaning, for a n55 motor build, could I swap in the n54 crank as a means to cut cost rather than buying a forged crank? It would make things cheaper.

The blocks are essentially the same. I don't see why bmw would have to go and machine a block differently.

[wgknestrick]

Waste of time and money imo. Find me an instant where the n55 crank is the weakest link. Crank is probably good up to 1000 hp

[rhm135]

From my understanding internal components are the same composition between N54 and N55. But the N54 has a closed deck block I believe. But I'm sure ask anyone with an N54 and the entire car is forged haha.

[loesch]

Based in this it doesn't..http://www.e90post.com/forums/showthread.php?t=196558

[Cloud9blue]

Originally Posted by rhm135

From my understanding internal components are the same composition between N54 and N55. But the N54 has a closed deck block I believe. But I'm sure ask anyone with an N54 and the entire car is forged haha.

They are all open deck. The only closed deck engine in the modern BMW engine line up is the S55.

[rhm135]

Originally Posted by loesch

Based in this it doesn't..http://www.e90post.com/forums/showthread.php?t=196558

I stand corrected. But that seems like great news. I mean considering the horsepower abuse that the N54 has taken with the N55 also being open deck.

[loesch]

Originally Posted by rhm135

I stand corrected. But that seems like great news. I mean considering the horsepower abuse that the N54 has taken with the N55 also being open deck.

Indeed it is!

[trixdout]

Originally Posted by wgknestrick

Waste of time and money imo. Find me an instant where the n55 crank is the weakest link. Crank is probably good up to 1000 hp

Granted with a inline 6, there are 5 center mains with a total of 7. In these cases the cranks can take alot more abuse versus a v6 config with only 4 mains total.

Seems as though the n54 can get up to 800+hp on e40 or whatever motiv did. From what I've read around, the crank is forged stock on the n54.

[wgknestrick]

Originally Posted by trixdout

Granted with a inline 6, there are 5 center mains with a total of 7. In these cases the cranks can take alot more abuse versus a v6 config with only 4 mains total.

Seems as though the n54 can get up to 800+hp on e40 or whatever motiv did. From what I've read around, the crank is forged stock on the n54.

Generally the crank is the strongest (and most expensive) internal component in any stock engine. If you are concerned about internals (I don't know why any n55 owner would be at this point), rods and pistons would be required well before an upgraded crank.

N55s just don't have the turbo options available to warrant wasting money on internals at this point until proven otherwise. You risk screwing something up more than righting a wrong. I wouldn't even think of internals until N55s start hitting +550whp on a consistent basis.

[JETmn]

Originally Posted by wgknestrick

Generally the crank is the strongest (and most expensive) internal component in any stock engine. If you are concerned about internals (I don't know why any n55 owner would be at this point), rods and pistons would be required well before an upgraded crank.

N55s just don't have the turbo options available to warrant wasting money on internals at this point until proven otherwise. You risk screwing something up more than righting a wrong. I wouldn't even think of internals until N55s start hitting +550whp on a consistent basis.

They have the same options available as the N54, but I just haven't seen much of anyone going for it. I am sure that is because the N55 cars are newer and have a higher value.