N52 and N54, what really is the difference?

Obviously, the N54 has twin turbos, but what is the difference in build?

In other words, are the heads, crankcase and all that stuff the same for both cars?

I imagine the fuel pump is different. Anything else?

They are completley different motors down to the block. Different everything.

Very very different engines - N52 is actually the more advanced design, lighter with magnesium and aluminum constuction, N54 is also a 2 piece design, but an all aluminum engine, so block, heads, intake, pretty much everything is different except some of the accessories that bolt onto it, like the electric water pump, alternator etc. N54 is also direct injection, so has 2 fuel pumps instead of just a low pressure one.

Originally Posted by Chaseme

Obviously, the N54 has twin turbos, but what is the difference in build?

In other words, are the heads, crankcase and all that stuff the same for both cars?

I imagine the fuel pump is different. Anything else?

No. The n54 is all aluminum (and allegedly the same block as the m54b30)
the n52 uses the newer magnesium aluminum block. Also the n54 also uses direct injection while the us n52 uses valvetronic with regular injection.

Fuel pump? Did he say fuel pump?

Originally Posted by hpowders

Fuel pump? Did he say fuel pump?

I love my fuel pump, and the 3 other ones that have failed on me.. To this day still does not drive me away from my car or have me thinking "I should have chosen another slower car"

Originally Posted by roadkillrob

Very very different engines - N52 is actually the more advanced design, lighter with magnesium and aluminum constuction, N54 is also a 2 piece design, but an all aluminum engine, so block, heads, intake, pretty much everything is different except some of the accessories that bolt onto it, like the electric water pump, alternator etc. N54 is also direct injection, so has 2 fuel pumps instead of just a low pressure one.

* The N54 has all aluminum crankcase with iron cylinder liners. The aluminum crankcase is pressure cast and differs from the "insert" design of the N52. This design is in contrast to the previous composite magnesium/aluminum crankcase on the N52. The construction of the N54 crankcase is to accommodate the increased torque output of the turbocharged N54.

* The N54 has the forged steel crankshaft (stronger) as opposed to the cast iron crankshaft in the N52.

* The N54 does not use valvetronic unlike the N52.

* Piston shape design in the N54 is different from the N52 to meet mixture formation requirements

* Crankcase ventilation system is different

* Both engines have an electric coolant pump, but the N54 has a 400W pump (9000 l/h), while the N52 has a 200W pump (7000 l/h)

For details see this sticky thread at e90post: http://www.e90post.com/forums/showthread.php?t=38856

Originally Posted by bmw325

No. The n54 is all aluminum (and allegedly the same block as the m54b30)

That's not true although it was rumored - the N54 is a completely new block design, unrelated to the previous-gen M54.

I was looking for a valve cover gasket replacement DIY and then only DIY I could find was for N52. What I have is an N54. Do you think that the DIY for N52 would also apply to N54? Thanks!

Here is the DIY for N52: http://forums.5series.net/topic/1151...with-pictures/