Where have other ppl mounted ther oxygen sensors for their EFI engines???

[Wisconsin_Snake]

I have a Classic Roadster that I am going to t power with a EFI 5.0 engine.... Where have other people installed their oxygen sensors??? My exhaust tubes to not combine till they are on the outside of the vehicle....

If you have pics that would be great too.
Thanks

[Excaliber]

A good question, and one I will be facing very soon myself. DScott, are the headers ready yet?

My concern is to keep them as close to the engine as possible for temperature and accuracy reasons. I wouldn't mind welding a bung hole in ONE of the runners IF that is better than moving it all the way out to the collector, which I worry about being to far away!

Ernie

[PSB]

I put the O2 sensor bungs in the #4 and #8 pipes. They need to be installed close enough to the head that the sensor will warm up quickly. It's a little hard to see in this pic, but it's the only one I have that shows the sensor location. The mess of wires was a temporary setup so I could test run my engine:




Pete

[jhaynie]

Look at all those wires!!! That looks scary

[65 Blur]

I installed an Edelbrock rich/lean indicator and placed the sensor about 3 inches downstream from the collector. It is facing in as close to the frame / body as possible, and has better clearance then the other low spots on the car. All of the modern O2 sensors have heaters built it, and they claim 30 seconds to warm-up and get a good reading.

I will try to get a picture to post.

Roy

[ls1ac]

Pointed in at about 30 degrees.
Covered with a heat sock, it is in the wind and will cool at highway speed in high gear.
Must read all gasses as one cylinder may not be indicating true gas content for engine.
Can not be seen except when looking down the side of the car.

[petek]

I'm using a Holley Projection 4Di system that has an O2 sensor. I mounted my sensor in about the same spot as Scott did in his picture above.

I talked with the Holley folks about monitoring only half of the cylinders (i.e. a single side pipe). They said that it will work fine.

My experience so far is that the O2 sensor warms up very fast, under a minute for sure (as monitored by watching the O2 reading on the screen of a laptop computer).

I haven't had any indication that airflow over the external part of the sensor is cooling the sensor to any significant degree (my sensor is tucked up pretty close to a frame rail under the car).

[Wisconsin_Snake]

Well I think I will call Ford motorsports and see what they about mounting it on just #4 and #8... If they are cool with it, that will work best for me as my side pipes are already nickle coated and there seems no decent place to mount the sensors there (frame issues).
Thanks all.

[Excaliber]

I'm going with 4 and 8 on mine as I feel the collector is too far away, maybe it is, maybe it aint. Sounds like one cylinder per side will work though.

Ernie

[petek]

Ernie,

Worked fine on my Cobra's pipes before I had them ceramic coated, works fine after I had 'em ceramic coated (O2 sensor located right at the point the four tubes collect together).

If you are using two sensors, how to you connect them together to feed the ECU? (Or does your ECU expect to have to sensors?)

[Excaliber]

ECU takes two sensors all ready. The three wire type, with the thord wire for quick warm up. I haven't got the new side pipes yet so will consider my options when they come in.

Ernie

[petek]

I wonder (and haven't the foggiest idea) if monitoring a single cylinder is a good idea or not. What I'm thinking is that if you monitor say 4 cylinders you'll end up with the sum of the cylinders. If one is a little lean, one a little rich, and the last few are fine, then everything sums together for a good reading. If you monitor a single cylinder and the cylinder tends to run a little lean, the ECU would (in effect) make all of the other cylinders a little rich.

Of course what would be really cool (and massive overkill) would be to monitor each cylinder and adjust the timing on individual injectors to keep each cylinder perfectly in tune!

[Excaliber]

Petek my concern is that as you get farther away from the heads the greater is the possibility of the exhaust gases not being at optimum temperatures. This may vary from vehicle to vehicle. With no way to read your "fuel curve" or "fuel air ratio" the engine may "feel" like it's doing OK, but there would be no way to be sure.

The third wire on the 02 sensor is for rapid warmup, I'm not sure it would hold the temp high enough and steady enough for regular engine temp driving. What the heck, maybe running a little rich is a good thing?

Ernie

[PSB]

There have been several FFR guys with 4 into 4 headers that have put the O2 sensors in only one pipe on each side and had no problems. I also asked the question on The Corral , and it's pretty standard procedure for running long tube headers on Mustangs. As long as everything is working right, the A/F ratio should be very close to the same on all cylinders. If you've got a bad injector or something on one of the cylinders that has O2 sensor, it would give a false reading to the computer. But if that's the case, you've got other problems.


Pete

[petek]

Well, there is the answer... either way works! Works down-stream on my car and up-stream on single runners on other folks cars.

Learn something new every day!