Euro cats: require lengthened EGT/O2 sensor wires?

[ATB88]

I've read that switching to euro cats requires lengthening the secondary O2 sensor wires in order for them to reach the section 1, is that right? (that is, if you want to run secondary O2s)

How about the EGT sensor, does that reach without modification or does that require lengthening as well?

I probably won't bother with the secondary O2s, but would like to run EGT for cat protection if it's not too much trouble...

[COVID-19]

I've read that switching to euro cats requires lengthening the secondary O2 sensor wires in order for them to reach the section 1, is that right? (that is, if you want to run secondary O2s)

How about the EGT sensor, does that reach without modification or does that require lengthening as well?

I probably won't bother with the secondary O2s, but would like to run EGT for cat protection if it's not too much trouble...

You just have to cut into the wire loom and run the O2 wires through the driver side. (Dont splice the O2 wires)

[ATB88]

You just have to cut into the wire loom and run the O2 wires through the driver side. (Dont splice the O2 wires)

Oh cool, that makes sense. I guess same for EGT since there's only one p/n for that. Thanks!

[COVID-19]

Oh cool, that makes sense. I guess same for EGT since there's only one p/n for that. Thanks!

I can’t remember if I bought some of that wire protector and added it. Also I believe they sell a euro o2 wire holder/bracket that goes on the lower driver side. I just zip tied them.

[Cubieman]

Next time my car is up in the air I'll snap some pics. The OE sensor mount can be used but must be modified to work. Zip ties and electric tape and/or conduit make more a clean look that is also protected from the elements. Basically you cut a slice down the entire length of the the conduit and pull out the O2s/EGT, they go down the driver's side and back to sec. 1. Just make sure you seal up the conduit after you slice it open, I used electrical tape and zip ties.

[8000RPM]

I used a couple of rubber insulated grommets from Home Depot and used the existing mounting location in the chassis. Worked perfectly.

[Casa de Mesa]

I used a couple of rubber insulated grommets from Home Depot and used the existing mounting location in the chassis. Worked perfectly.

Oh I like that. I'm about to do this too. In that pic, the grommets on the bottom of the pic are on the driver's side, correct?

I looked at the Euro sensor holder but also couldn't find a great reference on the web where someone installed it cleanly. I may still get the Euro holder but can get going down the road with the grommets. Thanks for that pic.

[Casa de Mesa]

Next time my car is up in the air I'll snap some pics. The OE sensor mount can be used but must be modified to work. Zip ties and electric tape and/or conduit make more a clean look that is also protected from the elements. Basically you cut a slice down the entire length of the the conduit and pull out the O2s/EGT, they go down the driver's side and back to sec. 1. Just make sure you seal up the conduit after you slice it open, I used electrical tape and zip ties.

Are you sure the EGT has to be routed down the driver's side too? Or are you just saying to cut the conduit containing the O2/EGT wires, route the O2s down the driver's side but keep the EGT on the passenger side?

I only ask because I pulled the factory headers this weekend and it *seems* like the EGT wires will be long enough down the passenger side, but I haven't gotten to the install process yet.

[JeST]

The post o2 sensors are definitely long enough, from factory, to reach the end of section 1.

[R1pilot]

The EGT stays the same. I am 99% sure.

The O2s I had to cut into the insulation to free up the wires and route them through the driver’s side.

I got all the factory clips from BMW to route the wires as the Euro cars have, they were cheap.

[R1pilot]

Changing the stupid starter was 10x more difficult than swapping headers/cats, btw.

[8000RPM]

Oh I like that. I'm about to do this too. In that pic, the grommets on the bottom of the pic are on the driver's side, correct?

I looked at the Euro sensor holder but also couldn't find a great reference on the web where someone installed it cleanly. I may still get the Euro holder but can get going down the road with the grommets. Thanks for that pic.

Yep, that’s down the driver’s side. The wires were long enough once you cut back the factory loom. I ended up adding new loom to replace pulling them out and taped up the joint. I bought the European bracket but ended up not using it. I liked the grommets better but maybe its preference?

[Casa de Mesa]

Sweet, good to know on all accounts. I may try to find the BMW brackets/clips but like the rubber grommet idea too.

[Cubieman]

I took the EGT down the drivers side. I really don't think it would have worked otherwise, I could be wrong..

[DanAvoN7]

Next time my car is up in the air I'll snap some pics. The OE sensor mount can be used but must be modified to work. Zip ties and electric tape and/or conduit make more a clean look that is also protected from the elements. Basically you cut a slice down the entire length of the the conduit and pull out the O2s/EGT, they go down the driver's side and back to sec. 1. Just make sure you seal up the conduit after you slice it open, I used electrical tape and zip ties.

I wanted to point out as I have seen others relocate the stock US rear o2 sensor plastic bracket from atop the valve cover to the driver side tunnel and did not shim the studs it normally mounts to on the valve cover. If you do not install shims on the studs then the plastic "M" cover won't sit level (have seen cars have a rattle due to this) and you can even crack it when installing the nuts that secure it.

You can get qty (2) of Genuine BMW OE shims which is part number 11127832085 or just source a generic spacer/shim from a hardware store and size it to the same stack height as the bracket. I can measure a shim later but off the top of my head I want to say it's ~5mm thick.