I'm going to put a 2012 1050 engine in my 2000 955i this winter, and I'm trying to work out the exhaust system at the moment.
My current understanding is:
- 05-10 exhausts have the catalytic converter in the mid pipe and the lambda sensor in the headers. If I just use the headers and a slipon I end up with a cat-free system and I can just put a bung in the lambda sensor mount.
- 05-10 headers should also have better compatibility with my frame than 11+, as the lower mounting tab used on the 05-10 is present on my frame but needs a hole drilling for the bolt to go through.
- The low mount slipon will mount from the rearset (I already have 1050 rearsets fitted) so I don't need to worry about my 955 subframe/pillion pegs not matching the slipon mounts. Also I prefer the look of a low mount
Having looked at the parts diagrams, it seems there are several versions of 05-10 headers:
Up to VIN 281465:
T2204732 (Non-cat) or T2204731 (Pre-cat)
VIN 281466 - 333178:
T2205680 (Pre-cat) or T2205570 (Pre-cat)
From VIN 333179:
T2205680 (Pre-cat) or T2204732 (Non-cat)
Looking at slipons confused me more, as most manufacturers seem to do separate systems for 05-06 and 07-10 year ranges. I'm guessing the 05-06 matches up with the "up to VIN 281465" headers and the 07-10 matches up with the 281466+ headers.
Can anybody help answer my questions:
1) Is my current understanding correct?
2) What's the difference between pre-cat and non-cat? They look identical on the parts diagrams and I would expect a big bulge for a cat in the "Pre-cat" headers.
3) I don't want a catalytic converter so I'm guessing I should aim for the non-cat headers. How can you identify which is which by looking at them when buying second hand?
3) Aside from the cat/non-cat issue, is there any reason to prefer a particular year range of headers over the other? How does this relate to the slipon year ranges?