Golden80

I ordered a pair of Dynomax Cerama-coat headers and I have a computer controlled QJet with an O2 sensor. Do they drill a hole for it or have I ordered the wrong headers? Also...is there anywhere I could find a Y-pipe or does anyone have one laying around they could sell?

Thanks,
Matt


[Modified by Golden80, 11:04 AM 8/25/2001]

Twin_Turbo

You can buy a weld bung for an O2 sensor, drill a hole and weld it in. Place the sensor in the header or in the reducer, anyway as close to the head as possible.

Marck

1yy07

I think you have orderd the wrong header. Call them and ask!! DO NOT DRILL the header!

BSeery

What he said -- check to see if they offer a header with the 02 sensor. If not check with them about putting the O2 sensor in the reducer (where it goes from the 3" flange to whatever size pipe you are running).

On a normal header I would say drill a whole on the drivers side colletor and weld in a bung. But, these are thermal coated. The welding would ruin the coating.
If you HAVE to, do what I mentioned above. Put it into the drivers side collector.
Any good muffler shop can do this for you.

Golden80

I've also gotten a suggestion to get a heated O2 sensor and put it into the Y pipe. Would this be a good idea? And also...would I need a 3 wire O2 sensor then?

Thanks,
Matt

Ken73

Actually, get a bung, weld it into the *reducer* so you don't ruin the coating on the header itself. IIRC, you have the California 305 that used the ECM controlled Q-jet and HEI setup. (Basically same thing they used on the 350 the next year.) The reducers are most likely NOT coated, and would be a good candidate area for the O2 sensor. I don't think they make headers with an O2 fitting at all - this is something your muffler shop will have to do (if you don't have the equipment to yourself.)

3 wire heated is not necessary, but isn't a bad idea. (3-wire = heated.) I'm not sure what the application is that would get you the 3-wire though, you might have to ask your local parts guy if you can rummage through the sensors. They're all NB (narrow band) sensors, so it won't make a difference from one to the other. (Although Honda does have a 5-wire wide-band O2 sensor, and it WON'T work for this.)

Ken

Golden80

I got the three wire O2 sensor online from oxygensensors.com. I also ordered a bung to install it. I've ordered quite a few little things for the headers. O2 sensor, ARP bolts, SME Copper gaskets, and the headers and cat. Can't wait to get this stuff installed. And in September I'm getting mufflers.

Matt

fireball

I put the O2 sensor in the reducer just past the flange on the header (I didn't want to unwrap the heat shielding from my headers). This setup works fine. Also, I have a 3 wire heated sensor on the driver side and a 1 wire on the passenger side. I can't tell a difference other than the 3 minute warmup on the 1 wire sensor. I'm only using this setup for a guage, so if your computer requires it you may have to be more concerned about placement.

UKPaul

Looking into Headers for my '81 I got this advise: The O2 sensor needs to be as close to the head as possible. This would mean that the computer would only be monitoring the O2 from one pot. If it is put in the collector then the exhaust gasses would have cooled down a fair bit & may give the wrong readings. Get round this by exhaust wrap and/or heated sensor.
It was quite difficult getting info on this but the above was the general opinion of the exhaust gurus. The most frequent answer was "Throw the computer away" (as if I could afford a new dist./carb after shelling out for Headers!!).
Good luck & could you let me know the end result?
Paul