N20 engine differences

D

davemul

Member
If this website can be believed, its a good overview of the differences between the 18i, 20i and 28i engines. apparently they are not the same as many on various forums have said. Seems the 20i has different pistons for a higher compression ratio but runs much lower boost than 28i. http://mywikimotors.com/bmw-n20/. So simply remapping a 20i to a 28i map is not the same as an original 28i which has lower compression ratio and bigger exhaust - or so they say :).
 
I thought I had read that RealOEM has the same part numbers for the 18i, 20i, 28i? Can't say I've looked though....
 
Hello, the one variant with different compression ratio pistons was used for a minority variant that was not used for the main North American/Europe markets.

All the 18i/20i/28i variants of the E89 use the same basic engine ...there were revisions to all engines over their production life...

Cam chains/tensioner, oil pump are the main ones..

Also late in 2012 the N20 went from a pneumatic controller for turbo wastegate management to an electrical version..

For reasons I don’t understand they had part number variants on the turbos but it’s not clear if that was material..

Anecdotally there is no evidence to suggest that remaps as opposed to plug in boxes don’t yield the same numbers across all 3 N20 variants used in the E89..
 
davemul said:
If this website can be believed, its a good overview of the differences between the 18i, 20i and 28i engines. apparently they are not the same as many on various forums have said. Seems the 20i has different pistons for a higher compression ratio but runs much lower boost than 28i. http://mywikimotors.com/bmw-n20/. So simply remapping a 20i to a 28i map is not the same as an original 28i which has lower compression ratio and bigger exhaust - or so they say :).
Click to expand...

That site talks about models that are not z4’s, in the uk all z4 cars using the n20 have identical engines & the Bmw sales literature gives identical compression ratios across the range.
The exhaust system is also identical, these parts are easily checked on realoem.com :thumbsup:
Rob
 
Confusing isn’t it. The article doesn’t mention a 184bhp engine that is not the 11:1 version, says its used in 20i and in E89, So the article is either wrong or incomplete then. I agree realoem lists the same part number for pistons for both 20i and 28i e89. I just find it odd that BMW would make an engine with different compression ratio for a lower pressure turbo that happened to have exactly the same BHP (184) as another engine used in the Z4 that has 10:1 compression.
 
davemul said:
Confusing isn’t it. The article doesn’t mention a 184bhp engine that is not the 11:1 version, says its used in 20i and in E89, So the article is either wrong or incomplete then. I agree realoem lists the same part number for pistons for both 20i and 28i e89. I just find it odd that BMW would make an engine with different compression ratio for a lower pressure turbo that happened to have exactly the same BHP (184) as another engine used in the Z4 that has 10:1 compression.
Click to expand...

Different markets, different requirements I guess? I think the USA f30 had a different compression engine.
All UK z4 cars using the n20 are the same though, including the exhaust/turbo/intercooler etc :thumbsup:
Rob
 
Pbondar said:
Hello, the one variant with different compression ratio pistons was used for a minority variant that was not used for the main North American/Europe markets.

All the 18i/20i/28i variants of the E89 use the same basic engine ...there were revisions to all engines over their production life...

Cam chains/tensioner, oil pump are the main ones..

Also late in 2012 the N20 went from a pneumatic controller for turbo wastegate management to an electrical version..

For reasons I don’t understand they had part number variants on the turbos but it’s not clear if that was material..

Anecdotally there is no evidence to suggest that remaps as opposed to plug in boxes don’t yield the same numbers across all 3 N20 variants used in the E89..
Click to expand...
NERD :worshipbmw:
 
mcbutler said:
Pbondar said:
Hello, the one variant with different compression ratio pistons was used for a minority variant that was not used for the main North American/Europe markets.

All the 18i/20i/28i variants of the E89 use the same basic engine ...there were revisions to all engines over their production life...

Cam chains/tensioner, oil pump are the main ones..

Also late in 2012 the N20 went from a pneumatic controller for turbo wastegate management to an electrical version..

For reasons I don’t understand they had part number variants on the turbos but it’s not clear if that was material..

Anecdotally there is no evidence to suggest that remaps as opposed to plug in boxes don’t yield the same numbers across all 3 N20 variants used in the E89..
Click to expand...
NERD :worshipbmw:
Click to expand...

I’d rather use the description “clued up” :thumbsup:
Rob
 
davemul said:
ars using the n20 are the same though, including the exhaust/turbo/intercooler etc :thumbsup:
Rob
Click to expand...

I wouldn't put much faith in that website. It's just a wiki article.

realoem is based off the BMW parts catalogue itself straight from the manufacturer so an almost perfect reference for variances.
 
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