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      06-26-2011, 02:56 PM   #1
Enlisted Member

Drives: 2011 128i 6MT, sport pack
Join Date: May 2011
Location: Lansing, MI

iTrader: (0)

Anyone's N52 have secondary cats?

My understanding has been that the N51 has an extra pair of cats in addtion to the cats in the exhaust manifolds. It also is supposed to have lower compression and the two stage intake manifold to make up for any power loss from the extra cats and lowered compression.

The different exhausts can be seen in the attached images from real oem. I noticed my 128i has the secondary cats shown for the N51 but does not have the two stage intake. According to my VIN I'm supposed to have an N52 and the block is stamped N52B30 right next to the serial number.

I'm curious to know who else has these extra cats on an N52.
Attached Images