Oxygen sensor in side pipes

[Boiler Ben]

I am looking for advice for adding an oxygen sensor port for a EFI system. I am building a Ford FE engine for my MK4 and have the FFR long tube headers which are separate pipes all the way to the flange. I did the side pipe delete and had planned to purchase side pipes from Gas-N. There seems to be a short section of pipe between the collector and the muffler. And it seems a port could be pointed ~4:00 position or possibly ~10:00 position by putting a hole into the body and running the cable into the passenger footbox. Any advice on doing this?

[MikeHolt]

Take at post #278 here, where Greg put his.

https://thefactoryfiveforum.com/showthread.php?46723-Gbranham-s-MkIV-427-IRS-TKX-Build-Thread-Winter-Storage-Time/page7

[John Ibele]

OP - yep, you got it. For long tube headers, 4-into-4 you have to go to just after the collector. At the 4 o'clock position it's not in the top half of the pipe as Holley recommends, but I haven't heard of this ever being a problem. And in the case of a roadster with this setup, there's no better choice.

Also, it's not unusual to go through an O2 sensor when dialing in your tune, so have your louvered vent (on this side at least) be removable for easier sensor replacement. One way to give your O2 sensor a little additional protection is the Innovate Motorsports item in the second photo - acts as both heat sink and shroud to protect from thermal shock due to condensation hitting the sensor directly. Another piece of car jewelry that only you will know about, but I think this one's worth it.

https://live.staticflickr.com/65535/53097387447_5b1038d1d6_b.jpg (https://flic.kr/p/2oU2Zpn)
Untitled (https://flic.kr/p/2oU2Zpn) by John Ibele (https://www.flickr.com/photos/familycobra/), on Flickr

https://live.staticflickr.com/65535/54001115382_bfce6d90b9_b.jpg
(https://flic.kr/p/2qgTQeu)20240809_233833826_iOS 1 (https://flic.kr/p/2qgTQeu) by John Ibele (https://www.flickr.com/photos/familycobra/), on Flickr

[Mike.Bray]

What Holley says about mounting the O2 sensor.

222331

I have a Fast Sportsman and here's what they say.

222332

Mine is mounted in the header collector using the bung FFR installs.

222333

[weendoggy]

Mine are in the side pipe collector. Running Holley HP for over 12yrs. Replaced 2 sensors.

222337 222338 222339

[Boiler Ben]

Thanks for the advice. Any tips for getting the perfect placement for the bung on the side pipe? Maybe there’s no science to it, just eyeball it as best you can with the pipe mounted?

[John Ibele]

Thanks for the advice. Any tips for getting the perfect placement for the bung on the side pipe? Maybe there’s no science to it, just eyeball it as best you can with the pipe mounted?

Yep, I mounted the pipe, and clamped on something which would point radially out from the center of the pipe, essentially. Then rotated to the desired location, marked with a Sharpie, and headed off to the welder.

[John Ibele]

What Holley says about mounting the O2 sensor.

222331

I have a Fast Sportsman and here's what they say.

222332

Mine is mounted in the header collector using the bung FFR installs.

222333


Take at post #278 here, where Greg put his.

https://thefactoryfiveforum.com/showthread.php?46723-Gbranham-s-MkIV-427-IRS-TKX-Build-Thread-Winter-Storage-Time/page7

OP says long tube headers, gents. Which means his first opportunity to sniff 4 cylinders is in the side pipe. Look up long tube headers or four into four.

[weendoggy]

^ I did read his post. Mine are 4-into-4. What's your point?

[John Ibele]

^ I did read his post. Mine are 4-into-4. What's your point?

My point was that the two folks I quoted were potentially confusing the OP. Note that you weren't one of them. You and I both gave answers appropriate to the OP's build configuration.

[Boiler Ben]

Yes, I get it. I was trying to understand how a sensor on the side pipe would be oriented in a convenient way and how to mark it so my machine shop can put it in the exact right spot. To sense 4 cylinders, there is only that one spot to do it. At about 4:00 position, it isn’t ideal per Holley, but at least it’s not fully at the bottom and I can just plan ahead for needing to replace it someday.

[Mike.Bray]

OP says long tube headers, gents. Which means his first opportunity to sniff 4 cylinders is in the side pipe. Look up long tube headers or four into four.

I didn't realize Holley or Fast's instructions were confusing. If that's the case maybe just stick to carburetors.

[John Ibele]

I didn't realize Holley or Fast's instructions were confusing. If that's the case maybe just stick to carburetors.

Who said the instructions were confusing? I certainly didn't. I said the OP could potentially be confused by information that doesn't pertain to his question or his build configuration. I notice he clicked with my response and didn't respond to yours, which should tell you something. I'm out.

[CraigS]

I know it's common theory that sensing 4 cylinders is better. But what if one did a little research on intake manifold runners design etc., and it's effect on getting an even mixture to all cylinders? Since that doesn't happen perfectly, why not pick the leanest cylinder and sense there. Keep the sensor in the engine compartment out of the way and get it warmed up more quickly since it is closer to the combustion.

[Mike.Bray]

Who said the instructions were confusing? I certainly didn't. I said the OP could potentially be confused by information that doesn't pertain to his question or his build configuration. I notice he clicked with my response and didn't respond to yours, which should tell you something. I'm out.

OP said I am looking for advice for adding an oxygen sensor port for a EFI system. I posted information from Holley and Fast on how to mount the O2 sensor. Perhaps you didn't understand it?

But you might just need to bear with me, I don't really know much about cars, engines, EFI or headers. But I did Google headers and learned a lot! Thanks for that tip.

[Mike.Bray]

I know it's common theory that sensing 4 cylinders is better. But what if one did a little research on intake manifold runners design etc., and it's effect on getting an even mixture to all cylinders? Since that doesn't happen perfectly, why not pick the leanest cylinder and sense there. Keep the sensor in the engine compartment out of the way and get it warmed up more quickly since it is closer to the combustion.

One of the reasons single plane intakes are preferred for EFI, especially with throttle body systems. And port injection is better than throttle body injections.

Some EFI systems like the Holley have means to tune individual cylinders although I've never gotten that deep into it.

[rich grsc]

Which is done by being a Master plug reader. :rolleyes: Holley can only test one oxygen sensor on the Terminator line.
Mike have you used the Terminator? Going to use one on a new engine in the spring. The wiring harness is massive, going to be a pain fitting it into the car.:mad:

[Norm B]

Well that degenerated fairly quickly.
I put the O2 sensor in the passenger side pipe at the 8 o clock position angled slightly up. Ran that way for a couple of years until we moved to a province requiring cats.
Picked the passenger side because that pipe moves down under hard acceleration while the driver’s side moves up. Less clearance between the body and sensor required on the passenger side.
Not familiar with Gas’n pipe construction but on FFR pipes the hole should be drilled so the rear edge is about 1 inch ahead of the collector to muffler weld. The muffler extends inside the collector.

HTH
Norm

[weendoggy]

Which is done by being a Master plug reader. :rolleyes: Holley can only test one oxygen sensor on the Terminator line.
Mike have you used the Terminator? Going to use one on a new engine in the spring. The wiring harness is massive, going to be a pain fitting it into the car.:mad:

Keep in mind Holley has three platforms, HP/Dominator (top), Terminator X/Max, and Sniper. The HP Terminator is not the same as the Terminator X platform. Also, all software is somewhat the same but different. My Terminator HP is the original (TBI no longer available), but you can run the Stealth TBI with it and the HP ECU. A lot to digest, but the HP series is the most advanced and can do a lot more than the other two. I would also stay away from their Dual Sync distributor and run a crank trigger setup. If you plan on port fuel, you're best be would be a crank trigger and CNP's with a cam sync unit. Much more stable than any carb system I know. Again, I see no issues with the O2 set at 7/8o'clock position. The nice part about the HP setup is if you run a TBI now and want to change to MPFI later, you won't have to buy a new system. Just add in the needed harness and go. jmo

[Boiler Ben]

Oh wow, thanks for the tip on that. Just from the photos, I can see the FFR pipes have a longer section before the muffler compared to Gas-N. Hadn't considered what's inside though. Shoot, I might end up regretting doing the exhaust delete on my kit.

[rich grsc]

Ya, it's a Terminator X. I see no issue running a Dual Sync, it's a lot simpler to use, it'll handle COP and sequential fuel

[weendoggy]

Ya, it's a Terminator X. I see no issue running a Dual Sync, it's a lot simpler to use, it'll handle COP and sequential fuel

Yeah, but they fail a lot, ask me how I know (https://www.weendoggy.com/fuel.htm#dsd). Save the headache of being stranded and put a crank trigger on.

[ProfessorB]

Thanks for the advice. Any tips for getting the perfect placement for the bung on the side pipe? Maybe there’s no science to it, just eyeball it as best you can with the pipe mounted?

I'm doing mine now. I took the bung and installed an old sensor in it. Played around with the position (with the side pipe still installed on the car) until I was happy with it. ( I made sure I could replace the sensor WITHOUT removing the side pipe.) Marked it with a sharpie. Drilled a 1/8 inch pilot hole....then used a step drill to enlarge the hole to size. I don't have pics yet (just got the bung back from the welder today) but it looks VERY much like the pics Weendoggy posted. The bung is at approximately 4 o'clock which is not ideal, but as Jeff pointed out in an earlier thread on bungs these cars sometimes require a little compromise (to be sure). I suppose that by being positioned at 4 o'clock it may get a little moisture and need replacement sooner but I just didn't want to notch or drill my body. And I did make sure that there's enough of an angle so the sensor can be replaced without removing the side pipe

[MikeHolt]

OP said I am looking for advice for adding an oxygen sensor port for a EFI system. I posted information from Holley and Fast on how to mount the O2 sensor. Perhaps you didn't understand it?

But you might just need to bear with me, I don't really know much about cars, engines, EFI or headers. But I did Google headers and learned a lot! Thanks for that tip.

Guess I don’t get it either! According to Gas’n web site, the FFR long tubes come with a bung already installed?

Though they don’t show a pic for an FE

https://www.gas-n.com/collections/factory-5-headers

[Boiler Ben]

It seems not many people are doing an FE engine in these. Or if they are, maybe not with EFI. So I have trouble finding references for what I’m doing. But I can confirm FFR long tube headers do not have a provision for O2 sensor. Before ordering my kit, I saw something about Gas-N side pipes (not headers) sounding better than the FFR side pipes. So when I ordered the kit, I did the side exhaust delete option. So I don’t have any side pipes yet but I am just getting started and won’t need them for a while. But the FFR ones look to have more room for a bung so maybe I made a mistake in my thought process. Not the first or last time for that though!

[Norm B]

I would contact Gas-N and discuss the O2 sensor location with them. Also, I wouldn’t get too hung up on Holley’s instructions about having the sensor pointed down. A lot of us have run with the sensor pointed slightly up with no issues. Our side pipes are a lot shorter and don’t retain condensation like most cars with long exhaust pipes behind the sensor location.

Norm

[rich grsc]

It seems not many people are doing an FE engine in these. Or if they are, maybe not with EFI. So I have trouble finding references for what I’m doing. But I can confirm FFR long tube headers do not have a provision for O2 sensor. Before ordering my kit, I saw something about Gas-N side pipes (not headers) sounding better than the FFR side pipes. So when I ordered the kit, I did the side exhaust delete option. So I don’t have any side pipes yet but I am just getting started and won’t need them for a while. But the FFR ones look to have more room for a bung so maybe I made a mistake in my thought process. Not the first or last time for that though!
Not sure where you are looking, but the headers do have an o2 bung: https://www.factoryfiveparts.com/16757-302-headers/?searchid=0&search_query=302+headers

[Norm B]

Not sure where you are looking, but the headers do have an o2 bung: https://www.factoryfiveparts.com/16757-302-headers/?searchid=0&search_query=302+headers

Rich, OP states the engine is a FE. The FFR headers, https://www.factoryfiveparts.com/16434-390-427-428-big-block-headers/?searchid=371308&search_query=Headers, for this application aren’t the new design.

Norm

[Boiler Ben]

That's true. But those are for a small block. The FFR headers for a FE engine (390, 427, 428) look like this.

[rich grsc]

I did not see them posted. Sorry, my mistake.