20i/28i piston differences?

[jamesgarbett]

Just been chatting to a remap guy in Stockport
I thought the N20 was mechanically the same regardless of output
But he says the 28i has different pistons?

 

[Smartbear]

Just been chatting to a remap guy in Stockport
I thought the N20 was mechanically the same regardless of output
But he says the 28i has different pistons?

They are the same, show me the difference on here https://www.realoem.com/
Rob

 

[jamesgarbett]

That's what I thought Rob
He is adamant that a 28i can take more power than a 20i - maybe this is a pricing thing

 

[Anonymous]

Just been chatting to a remap guy in Stockport
I thought the N20 was mechanically the same regardless of output
But he says the 28i has different pistons?

There were some N20 engines fitted to other BMWs but not E89s with different pistons and cams. These can give more power when tweaked.

The guys who tweaked mine (The Performance Centre Sunderland) stated this when we were discussing what / where / why in terms of tuning the N20.

So both statements are correct...all E89 N20s of the same age have physically identical units bar running changes.

But there are somewhere some N20s with slightly different exhaust cam / pistons

 

[Deepseaskateboard]

Just been chatting to a remap guy in Stockport
I thought the N20 was mechanically the same regardless of output
But he says the 28i has different pistons?

I had a look into this a while back:
https://z4-forum.com/forum/viewtopic.php?f=23&t=122568&p=1751722#p1751722

Some interesting points by other people too in the comments.

I think the drivetrain is identical, strangely on some remapping websites it shows the 28i being able to make more power and some show all being able to make 280bhp.

I guess until someone does a full strip down on both cars, no one will ever know!

I am wondering what would happen if someone did an ECU swap from a 28i onto a 20.

 

[Anonymous]

Just been chatting to a remap guy in Stockport
I thought the N20 was mechanically the same regardless of output
But he says the 28i has different pistons?

I had a look into this a while back:
https://z4-forum.com/forum/viewtopic.php?f=23&t=122568&p=1751722#p1751722

Some interesting points by other people too in the comments.

I think the drivetrain is identical, strangely on some remapping websites it shows the 28i being able to make more power and some show all being able to make 280bhp.

I guess until someone does a full strip down on both cars, no one will ever know!

I am wondering what would happen if someone did an ECU swap from a 28i onto a 20.

The key differences on the N20 are that earlier versions pre 2013 has pneumatic waste gate control, later ones had electrical waste gate control.

Most tuners believe because of the extra control that the EWG brings they can tweak the engines that bit further.

Some people have swapped 28i DMEs into 20i versions but its not a trivial task.

The tunes that piggyback the base tune tend to show bigger increases on the 28i DMEs.

However some of the more advanced tuners have actually got some of teh best numbers out of the 18is (which have EWG)

 

[sumotan]

Think I read somewhere that 28i has sligtly lower compression over the rest not sure if it's true.

Cheers

 

[Smartbear]

Think I read somewhere that 28i has sligtly lower compression over the rest not sure if it's true.

Cheers

They’re all the same, look at BMW’s own technical specifications
Rob