From bimmerpost
Link
http://www.e90post.com/forums/showthread...05&page=19
There has been a bit of misinformation floating around that we wanted to clear up. The newer N55 turbo with the 4" outlet is a different turbo all together. The wheel sizes are different. You can't just swap over the bigger outlet (which is the whole turbofold). Also, the bigger outlet is not the reason the newer N55 makes a bit more power. It makes more power because of the DME tune, the larger turbine and compressor wheels, and all the other different supporting parts. We've had multiple people ask "can you add the 4" outlet to my turbo?". It doesn't work like that...
Hope that makes sense, Thanks.
Link
http://www.e90post.com/forums/showthread...05&page=19
There has been a bit of misinformation floating around that we wanted to clear up. The newer N55 turbo with the 4" outlet is a different turbo all together. The wheel sizes are different. You can't just swap over the bigger outlet (which is the whole turbofold). Also, the bigger outlet is not the reason the newer N55 makes a bit more power. It makes more power because of the DME tune, the larger turbine and compressor wheels, and all the other different supporting parts. We've had multiple people ask "can you add the 4" outlet to my turbo?". It doesn't work like that...
Hope that makes sense, Thanks.