[tscdennab]

Originally Posted by Aries932

Yes the crank in the N55 is not forged. If you are looking for higher turbo applications as far as upgrading turbos go...you want to buy a N54.

I also read that the N54 pistons may be forged. Do you have any info on this ? (does "Deckel" know ? )

It seems to me that BMW over-engineered the N54. N55 is a "simplified" N54 version, of course with the newer technology advances added.

[Aries932]

Originally Posted by tscdennab

I also read that the N54 pistons may be forged. Do you have any info on this ?

It seems to me that BMW over-engineered the N54. N55 is a "simplified" N54 version, of course with the newer technology advances added.

I have no clue about the pistons in all honesty.

[Elie335]

Originally Posted by Aries932

N54: Some cams are cast, some are lightweight hollow
N55: All cams are lightweight hollow

awesome informations indeed!

Can you tell wich built date comes with lightweight hollow cams?

[Aries932]

Originally Posted by Elie335

awesome informations indeed!

Can you tell wich built date comes with lightweight hollow cams?

Pretty sure if you go to this post Drakel has like 5 PDF's that go into more detail like you want.

http://www.1addicts.com/forums/showthread.php?p=9633909

[Elie335]

^^ ty for the link

[Constant.S]

The N55 is "economy oriented" therefor the VANOS system. Enough said.

[boostd92]

Originally Posted by Constant.S

The N55 is "economy oriented" therefor the VANOS system. Enough said.

Both engines have VANOS.

The N55 has Valvetronic. And though it's primary purpose is for better fuel mileage and emissions, it's also to promote a wider torque curve... ultimately, if you read the .pdf's with the N54/N55 differences, the valvetronic motors (N55's) came with bigger valves with higher lift. The engine is just an air pump, more in=more out=more horsepower.

[Boosted John]

Originally Posted by BoostedE90

It will be interesting to see what the N55 is capable of once tuners have more time under the hood. But wth that said when it comes to performance BMW prefers to use the N54 (IS model and the new M1). So that must mean something.

that is the same thing i think.. there has to be some advantage to it for them to choose it in those cars.... woo hoo N54

[Boosted John]

Originally Posted by tscdennab

I also read that the N54 pistons may be forged. Do you have any info on this ? (does "Deckel" know ? )

It seems to me that BMW over-engineered the N54. N55 is a "simplified" N54 version, of course with the newer technology advances added.

I don't think over engineered would be the right word. if that was the case, the cars would be able to take more than 15-20min worth of hot laps on a track..

[tibra1]

Originally Posted by symple84

Which engine yields better tunability, I know the N55 is fairly new but in the long run which of the two will get the significant gains??

Too soon to tell I think..the n55 is at the beginning stages..the n54 is much further along..but the lessons learned from the n54 will prolly help tuning the n55 quicker

[C4sF80M3]

Originally Posted by boostd92

Both engines have VANOS.

The N55 has Valvetronic. And though it's primary purpose is for better fuel mileage and emissions, it's also to promote a wider torque curve... ultimately, if you read the .pdf's with the N54/N55 differences, the valvetronic motors (N55's) came with bigger valves with higher lift. The engine is just an air pump, more in=more out=more horsepower.

True, but remember the biggest choke point is still the turbo. It really doesn't matter if the N55 has slightly large valves if the turbo can't flow as much air throw it. The engine will never see the additional volume of air. This is also why the RB turbos make more power than the stock turbos at the same PSI. The PSI is the same yes, but the volume of air is increased per PSI, therefore more HP. Besides with the cast bottom end, the N55 will be severely limited in how much additional power it can take before grenading. With some serious porting, the N54 heads can flow a lot more air, even without going to larger valves.