headers for obd1 s52?

[MaloventEvil]

I have been searching around, but haven't found a definitive answer either way...

I have an obd1 s52 that will be using the obd1 harness.

As I understand it, if i buy headers with 2 o2 ports, I will need to plug them and have a single o2 sensor bung installed at the collector? (I read that the s50 harness only supports a single o2 sensor?)

Thanks!

[hoveringuy]

I used a single port at the header so my O2 sensor was only sampling 3 cylinders. It stays hotter that way but CARB wouldn't like it.

[MaloventEvil]

But am I correct about the s50 harness only supporting 1 o2 sensor? if so, is there any advantage to the s52 headers vs s50 specific ones?

[5KWattson]

not sure how the S50 harness varies from a M50 but the o2 on mine is wayyyy down stream right infront of the CAT

[Gnarles]

You are correct that obd1 (S50) only supports 1 o2 sensor. Ideally you want to sample from all 6 cylinders which is why the stock obd1 e36 exhaust has the o2 sensor where the two downpipes merge.

[hoveringuy]

Ideally, yes. I have had negative problems sampling from only 3. When I did have an O2 sensor way downstream I had problems with it getting too cold.

[MaloventEvil]

so i guess that leads me to my next question.. if the s50 harness only supports 1 o2 sensor, why do people use the s52 headers and go through all the hassles when they can just buy s50 headers? are the s52 headers better performing?

i was planning on wrapping the exhaust so hopefully it gets warm all the way down by the collector.

[Mossman]

Stock location for S52 is pretty far down stream, just in front of cat. Find it weird you had problems.

You are correct that S50 harness only needs 1 o2 sensor. OBD2 headers look a lot better I don't know how much better they flow. I mean S50 makes 240hp thru cast iron obd1 headers so they can't be so bad.

[MaloventEvil]

so my current plan is to buy these:

http://cgi.ebay.com/ebaymotors/92-93-94-95-96-97-98-E36-323-325-328-M3-2-5-2-8-HEADER-_W0QQcmdZViewItemQQhashZitem2c5486a0bdQQitemZ190396670141QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

and block off those two o2 bungs and put a single one at the collector. Is this 100% correct?

Thanks again! I just don't want to spend the money until I confirm I am not wrong :)

[Mossman]

As long as you're ready to massage headers and/or subframe that sounds like a plan

[sharky]

I use a stock all the way through OBD2 E36 M3 exhaust, plugged the post cat 02's and bungged1 downpipe for the single obd1 o2, works fine, maybe not ideal but fine none the less.

[Kingb]

so my current plan is to buy these:

http://cgi.ebay.com/ebaymotors/92-93-94-95-96-97-98-E36-323-325-328-M3-2-5-2-8-HEADER-_W0QQcmdZViewItemQQhashZitem2c5486a0bdQQitemZ190396670141QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

and block off those two o2 bungs and put a single one at the collector. Is this 100% correct?

Thanks again! I just don't want to spend the money until I confirm I am not wrong :)

These are the same headers that I bought. Havent installed them yet but that is how I am going to do my 02. It comes with both plugs.

[dinanm3atl]

The actual wire is an AFM style spin on plug. Mine is bolted next to the trans. It is WAY downstream and the wire on the Bosch 02 is also SUPER long. So the bung is just after the collector to get a good reading.

You will simply use a plug(exhaust shop has them) or get the eBay or similar headers. Mine had plugs in them already.

so my current plan is to buy these:

http://cgi.ebay.com/ebaymotors/92-93-94-95-96-97-98-E36-323-325-328-M3-2-5-2-8-HEADER-_W0QQcmdZViewItemQQhashZitem2c5486a0bdQQitemZ190396670141QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

and block off those two o2 bungs and put a single one at the collector. Is this 100% correct?

Thanks again! I just don't want to spend the money until I confirm I am not wrong

That is essentially what I have. They come with the bungs and plugs installed. Just make sure they are tight.

Stock location for S52 is pretty far down stream, just in front of cat. Find it weird you had problems.

You are correct that S50 harness only needs 1 o2 sensor. OBD2 headers look a lot better I don't know how much better they flow. I mean S50 makes 240hp thru cast iron obd1 headers so they can't be so bad.

They flow better. Just looking at them you can see the difference in quality.

As long as you're ready to massage headers and/or subframe that sounds like a plan

Not always required. Mine aren't massaged and didn't require beating them up or anything.