Hey guys,

I wonder what are the differences between a N18 Cooper S and a N14 JCW, same year.
I got the opportunity to "upgrade" my Automatic N18 S (245 lb-ft, 210 HP) to a stock Manual N14 JCW
I searched the forum and found some differences, but no one did a comparison between N18 S vs N14 JCW

 

They are mechanically and electrically different.
The ECUs are different, the cams are different, the oil pumps are different, the JCW has a slightly bigger turbo and it is tuned...

 

N14 JCW have slightly lower internal compression, different head gasket, larger turbo, larger MAF ..lots of other little bits. They have VANOS (aka BMW vtec, on intake cam only). N14's get a bad rep from all the MCS N14's folks blow up.. pretty rare to find an N14 JCW owner that isnt happy.

N18 have higher compression, different head gasket, smaller turbo..smaller MAF and other bits. They have VANOS on intake and exhaust cam. Oil pressure is ECU regulated.

Overall there is greater upgrade path on the N14 platform. Many folks will recommend the N18 as it does not exhibit the same carbon coking issues, seen in the N14 head and valves. Either is a good choice as long as you realize youre buying a high performance turbo ..and maintain it so (good oil 3-5k mi).

 

Per realoem.com, the head gasket and bolts are the same for the N14 and N18 (i also just did an 09 JCW head using N18 gasket and bolts).

I personally dont mind the N14 and do have the jcw. Maybe those guys had issues because they were following the dealer's recommended 10k oil change interval!

 

I think I will stay with my N18 MCS
Is there anything I can do with the crappy seats? I REALLY want the recaro ones

Those the ones I got

 

for accuracy sake: 2ng gen JCW uses a thicker headgasket vs a non-JCW regardless of N14 or N18. This partially accounts for the lower compression, as well as the small decrease in CR from 10.5:1 -> 10.0:1 (MCS vs JCW)


measure them.. they are not the same