SuperSprint High Flow Cat Install

[SGM330]

Hey Guys,

I picked up SS headers and cats last year and installed them yesterday. Need to button up a few things but excited to drive it!

Does anyone have pictures of how they routed their O2 sensors to the cats? The location is much further away from the original position and I haven't seen much information on this topic. If you could share how they're routed under the beauty cover as well would be great since I've noticed it needs to hang off the back of the valve cover to simply reach the cats.

Much appreciated! Thanks!

[repoman89]

There was a lot of information on the old forum about how to do it. Basically you need to slice the wiring loom behind the engine to free some wiring then rewrap it. Or buy the Euro O2 sensor harness ($$$ I think now, used to be cheap-ish).

Or, my preferred option if I was to do it from scratch, just delete the post O2 hardware and plug the bungs. You’re going to have to turn off the cat efficiency codes anyway and that’s all those downstream O2s do.

[PSUEng]

You'll need to cut the grommet and pull your secondary O2 and EGT wiring out of the grommet where they all pass through the beauty cover and then cut the corrugated wire protection and pull the wires out of the loom, all the way back to the rubber grommet that the corrugate wire sheathing seats to. I used DEI high temp wrap around each set of wires, and then routed them down under tunnel. I'll try to dig up photos, but search this forum there is good info.

Here is what you will be dealing with, before cutting the corrugated protection:


Cut back to here:


Split them all out and wrap them in DEI high temp wrap, ready for routing down the tunnel...

DEI..



Prepped for my installer...



I would also strongly suggest you get all new BOSCH O2 sensors "while you're in there". I did that, and ran the FCP "OEM" EGT, so far so good

EDIT: I gave my BMW shop a few of these: 12521437136 clips and they were successfull using them to route along the heat shield.

[AWE46M3]

You're the man PSUEng - have not seen the last couple of pictures you posted anywhere else on the forums. Appreciate you.

[heinzboehmer]

Other option is to remove the O2 harness and fish the appropriate wires out. Few hours work and much cleaner than cutting: https://nam3forum.com/forums/forum/m...221#post131221

[PSUEng]

Other option is to remove the O2 harness and fish the appropriate wires out. Few hours work and much cleaner than cutting: https://nam3forum.com/forums/forum/m...221#post131221

Now THIS is the ultimate completist approach!!! I know, you and I conversed on this a while back, and I didn't do it.

[nuc1]

Or, my preferred option if I was to do it from scratch, just delete the post O2 hardware and plug the bungs. You’re going to have to turn off the cat efficiency codes anyway and that’s all those downstream O2s do.

That's what I did. Easy and less O2 sensors to worry about.

Mike

[SGM330]

Thanks for the great options and suggestions!

I was able to make them reach for now to get the car home since I was on a rented lift. Without extending them with either solution but now I can't re-install the beauty cover. For the interim period, since we don't have emission testing here I'm going to delete the post cat sensor and work on the harness on the side for when I need them. If we don't introduce emission testing, I'll leave them off.

Does anyone know if the post cat o2 sensor harness from an non m the same as M? I'd rather buy one from the scrap yard and build upon that

[DJM]

There is a sticky: DIYs by Obioban at the top of the e46 page. O2 sensor extension to section 1 is one of them. You route them to the left side of the engine.

[AWE46M3]

There is a sticky: DIYs by Obioban at the top of the e46 page. O2 sensor extension to section 1 is one of them. You route them to the left side of the engine.

Great call out - link to DIY post below:

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/542-extending-o2-wiring-for-section-1-with-cats-repost-pdf

[AWE46M3]

I did that, and ran the FCP "OEM" EGT, so far so good

EDIT: I gave my BMW shop a few of these: 12521437136 clips and they were successfull using them to route along the heat shield.

Nice! Adding those clips to the FCP cart


Just spent the last hour researching the part numbers so want to drop these below for anyone else researching the topic. Link to RealOEM Diagram


EGT Sensor – 11787831624

BOS - 13949 - Oxygen Sensor - Position: Upstream Front, Before catalytic converter, cylinders 1-3 - 11781743994

BOS-13952- Oxygen Sensor - Position: Upstream Rear, Before catalytic converter, cylinders 4-6 – 11781405324

BOS-15138 - Oxygen Sensor – Position: Downstream Front, After catalytic converter, cylinders 1-3 - 11781406621

BOS-13951 - Oxygen Sensor – Position: Rear, After catalytic converter, cylinders 4-6 – 11781406622


As an aside/ FYI: