A/F Meter Bung Placement ?

[ProfessorB]

I'm probably going to install a wide-band air/fuel meter in the near future. Looking for advice, specifically, about bung placement and I would welcome any other advice (brand, model, etc) as well. I know very little at this point, just getting my head into the game. All I know is that ideally, the bung should be "on the collector" which to me says outside of the body. I would prefer to install it "in situ" without removing the header but don't know if that's possible. Just wondering what other guys have done. Thanks.

[gbranham]

No, not outside the body. The collector on the headers is where the 4 pipes combine into one. Here's mine, installed in the bung in the FFR SBF headers.

Greg

220726220727

[ProfessorB]

No, not outside the body. The collector on the headers is where the 4 pipes combine into one. Here's mine, installed in the bung in the FFR SBF headers.

Greg

220726220727

Thanks Greg, but that won't work for me. There IS a flange just inside the body but it's individual tubes on both sides of the flange., and I have four tubes for the first 8 inches outside the body.220736

[CraigS]

I put mine in the side pipe. You can see the plugged bung at the bottom of this pic.
220757
I just ran the wire up over the door when I wanted to do some tuning. Otherwise it was plugged. A good welder could probably do a little better job installing the bung more recessed into the pipe and maybe find a plug that protrudes less.

[ProfessorB]

I put mine in the side pipe. You can see the plugged bung at the bottom of this pic.
220757
I just ran the wire up over the door when I wanted to do some tuning. Otherwise it was plugged. A good welder could probably do a little better job installing the bung more recessed into the pipe and maybe find a plug that protrudes less.

Thanks, Craig. I hadn't thought of that (using a plugged bung). Still, I liked the idea of having a full-time operating gauge on the dash. I have thought of putting the bung at the inside "3 oclock" position (driver's side) and running the wire inside a flexible (spiral wound) metal sheath. Maybe if the sheath was flat black it wouldn't stand out too much?
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Regarding your own bung, I think it looks just fine. And it's the best position for part-time duty.

[narly1]

I have thought of putting the bung at the inside "3 oclock" position (driver's side).

I believe prevailing wisdom suggests that O2 sensors be oriented somewhere between 9 and 3 o'clock, so that they don't end up being places where condensation pools.

Earl

[bobl]

They make angled bungs and adapters now. You could install it in the collector at the 90 deg point and then have it angled parallel to the pipes next to the body. I've run several straight out the side under the body. They've lasted many years on closed loop efi applications, but did have occasional failures. I know of a Backdraft that they notched the body for clearance. I'm not a big fan of that approach.

Bob

[ProfessorB]

They make angled bungs and adapters now. You could install it in the collector at the 90 deg point and then have it angled parallel to the pipes next to the body. I've run several straight out the side under the body. They've lasted many years on closed loop efi applications, but did have occasional failures. I know of a Backdraft that they notched the body for clearance. I'm not a big fan of that approach.

Bob

I'm not a big fan of that approach, either. (LOL) Which makes me realize: I don't know what the sending unit (sensor) looks like, probably because I haven't selected the brand and model of wide-band meter yet. I am looking for input and recommendations there, also As I said in my first post,I'm just getting my head in the game. At this point, I'm wondering how far the sensor "sticks out" outside the collector.... I did just Google bungs and found a "J style" bung which positions the sensor parallel to the collector, sold by Vibrant Performance.

[gbranham]

They look like any other oxygen sensor, pretty much. The one in my picture is a wideband sensor. What do you plan on using the wideband setup for? You're obviously new to all of this, so I assume you're not going to be tuning an EFI system. Do you simply just want to see your A/F ratio?

[MB750]

Put it in the collector, but point it straight under the car. Don't go lower than horizontal. Then seeing the bung will be minimal. Also, buy a bung with a plug, just in case you remove the sensor.

I usually buy them in bulk, I put my wideband on everything for tuning.

[ProfessorB]

Put it in the collector, but point it straight under the car. Don't go lower than horizontal. Then seeing the bung will be minimal. Also, buy a bung with a plug, just in case you remove the sensor.

I usually buy them in bulk, I put my wideband on everything for tuning.

. I'm going to consider that option, as well as the "J bung" option. About the J bungs, there are several styles available with wider or "closer" radius in the 90 degree bend. This one, from Vibrant Performance, is a "close radius" example...220799220799

[Jeff Kleiner]

I've put them here pointing inward and they clear the body:

https://thefactoryfiveforum.com/attachment.php?attachmentid=93734&d=1537273234

Yes, they are below the preferred horizontal but none of the cars have ever experienced O2 sensor problems. Sometimes these cars require reasonable compromises.

Jeff

[ProfessorB]

They look like any other oxygen sensor, pretty much. The one in my picture is a wideband sensor. What do you plan on using the wideband setup for? You're obviously new to all of this, so I assume you're not going to be tuning an EFI system. Do you simply just want to see your A/F ratio?

Sorry for missing your question earlier. Yes, just want to watch my A/F meter (changing carbs) not going to EFI. Having one would take the "Black Art" aspect out of tuning a carb. On that subject, I haven't even selected a wide-band kit yet. Some of them are quite reasonably priced but some have poor reviews. I can use some input on selecting a good kit. I've seen them as low as $200 range but it seems the quality is MUCH better with a little more money.

[ProfessorB]

I've put them here pointing inward and they clear the body:

https://thefactoryfiveforum.com/attachment.php?attachmentid=93734&d=1537273234

Yes, they are below the preferred horizontal but none of the cars have ever experienced O2 sensor problems. Sometimes these cars require reasonable compromises.

Jeff

Thanks, Jeff. In my view, that would work for me well. (Besides, I wonder if, when using a J-bung, the wiring harness would get too much heat.)

[CraigS]

For a permanent install Jeff's pic is ideal. Don't worry about the sensor, it can take the heat. You could protect the wires though w/ some insulation sleave. But they are probably more vulnerable to debris hitting them than being melted. When I was doing carb tuning I used an Innovate LM1 recording unit similar to this;
https://www.summitracing.com/search/brand/innovate-motorsports/product-line/innovate-lm-2-digital-air-fuel-ratio-meter-basic-kits/part-type/data-acquisition?fr=part-type&ptr=data-acquisition&ptr_oos=1&SortBy=Default&SortOrder=Ascending&keyword=LM-2&utm_source=bing&utm_medium=cpc&utm_term=%2Binnovate%20%2Blm2&utm_content=Innovate%20Motorsports&utm_campaign=Brands%20D%20-%20L%20%28Search%29
I found that I would use it for a month or 2 then remove it. Later I might make a change so hook it up for another month. Mine was setup so I could make recordings and it put out a graph I'd look at on the PC. I did look at the display for some tuning (cruise and light throttle) but, especially for full throttle tuning, the graph was better. I found that full throttle in 2nd happened too fast so I used 3rd. But that obviously got me to higher speeds so I needed to be watching the road not a display. I actually had it in use for maybe 4 months when I first got it since it was all new to me. Then when I built a 408 to replace the 351 I used it again. Also when I went from a 650 carb to a 750. I really enjoyed the whole process. BTW if your fuel line to the carb has metal tubing between the front and rear bowls, replace it with a setup w/ AN hose between the two. One of the biggest pains was removing a float bowl to change jets inside. W/ the chance of leaks afterwards, you really only want to remove one bowl at a time. Oh, and buy reusable bowl gaskets. Get a small notebook and pencil to keep track of jet changes. I promise you, you will forget what you did 2 weeks ago and again, it's a pain to remove a bowl just to verify what jet is in there so you can order another one.

[ProfessorB]

For a permanent install Jeff's pic is ideal. Don't worry about the sensor, it can take the heat. You could protect the wires though w/ some insulation sleave. But they are probably more vulnerable to debris hitting them than being melted. When I was doing carb tuning I used an Innovate LM1 recording unit similar to this;
https://www.summitracing.com/search/brand/innovate-motorsports/product-line/innovate-lm-2-digital-air-fuel-ratio-meter-basic-kits/part-type/data-acquisition?fr=part-type&ptr=data-acquisition&ptr_oos=1&SortBy=Default&SortOrder=Ascending&keyword=LM-2&utm_source=bing&utm_medium=cpc&utm_term=%2Binnovate%20%2Blm2&utm_content=Innovate%20Motorsports&utm_campaign=Brands%20D%20-%20L%20%28Search%29
I found that I would use it for a month or 2 then remove it. Later I might make a change so hook it up for another month. Mine was setup so I could make recordings and it put out a graph I'd look at on the PC. I did look at the display for some tuning (cruise and light throttle) but, especially for full throttle tuning, the graph was better. I found that full throttle in 2nd happened too fast so I used 3rd. But that obviously got me to higher speeds so I needed to be watching the road not a display. I actually had it in use for maybe 4 months when I first got it since it was all new to me. Then when I built a 408 to replace the 351 I used it again. Also when I went from a 650 carb to a 750. I really enjoyed the whole process. BTW if your fuel line to the carb has metal tubing between the front and rear bowls, replace it with a setup w/ AN hose between the two. One of the biggest pains was removing a float bowl to change jets inside. W/ the chance of leaks afterwards, you really only want to remove one bowl at a time. Oh, and buy reusable bowl gaskets. Get a small notebook and pencil to keep track of jet changes. I promise you, you will forget what you did 2 weeks ago and again, it's a pain to remove a bowl just to verify what jet is in there so you can order another one.

Thanks Craig! All good advice. I'm on a limited budget in retirement...I bought the carb on sale but have to wait for funds to complete the project so I'm using the time to plan this out. The carb is a 750 with mechanical secondaries (engine is 427W). AN/hose fuel inlet is already on the shopping list along with re-usable bowl gaskets and extra jets. I haven't taken the bowls off yet to verify the jet sizes that are supposed to be in there (before ordering jets) but I plan to. I played with Holleys as a kid....always enjoyed the process (lots of plug reading back then. Always kept a notebook as you recommend.
I looked at the link you sent but have my heart set on a full-time dash display but I do agree it's difficult to watch a gauge and the road at the same time. I drove trucks for a living....I think I just like gauges. :o (Still researching those) I'll probably make a separate thread soliciting recommendations for them. Thanks again for your help and advice.

[MB750]

... I looked at the link you sent but have my heart set on a full-time dash display but I do agree it's difficult to watch a gauge and the road at the same time.

Much truth here. When I was tuning my AVS2, I'd have to do my WFO pulls in 2nd and 3rd because 4th was WAY over the speed limit that that RPM.