I finally ponied up for a new set of headers. Only issue is there isn't a bung for my o2 sensors, so I ordered some to install. Only two. I'm going with merged collectors, and am wondering where to install the bungs. Is the best place right before the narrowest part or right after? Can't and not doing 8 bungs, I just use the o2's for averages.....

Thoughts?

best is in a primary. otherwise as far away from the end as possible.

By reading your plugs, pick the cylinder on each side that is what I call, a pecky cylinder. It will be the one that looks like it has the most timing by the ground strap read and fuel is the leanest. If you use those two cylinders to tune by, all the others will be happy. Also install bung never down or level, should be at least 15 % up to keep it from collecting fuel.

quote:

Originally posted by Ron C.:
By reading your plugs, pick the cylinder on each side that is what I call, a pecky cylinder. It will be the one that looks like it has the most timing by the ground strap read and fuel is the leanest. If you use those two cylinders to tune by, all the others will be happy. Also install bung never down or level, should be at least 15 % up to keep it from collecting fuel.

Bungs are the angled ones, so no worries there. I'm limited to the collector for installation, they aren't coated yet...the headers themselves are....

3 and 6

if it were me, I would put them before the narrow part of the merge collector. My reasoning is reversion of fresh air would be less.


Joe

quote:

Originally posted by Coloradoracer:

quote:

Originally posted by Ron C.:
By reading your plugs, pick the cylinder on each side that is what I call, a pecky cylinder. It will be the one that looks like it has the most timing by the ground strap read and fuel is the leanest. If you use those two cylinders to tune by, all the others will be happy. Also install bung never down or level, should be at least 15 % up to keep it from collecting fuel.

Bungs are the angled ones, so no worries there. I'm limited to the collector for installation, they aren't coated yet...the headers themselves are....

You can still install “angled ones” incorrectly.

Your BEST install is in the primary tube.

If not, as close to the merge as possible. Maybe next to the calendar listed above. If you get it too close to the end of the collector, you will get false readings.

Happy new year!

If I could, I'd install 10 bungs total, get a race pack, and do 10 02's! But since I'm working with two, I'll do the best I can. As mentioned, I'm not installing them into any primaries...the headers are already coated. Collectors are not. I've managed to find a few pics of other headers of similar style with o2 bungs in them and they are located just before the narrow part of the collector. So that's where I'll locate mine. The other thing I'm going to do with this set is seal the primaries to the collectors. My current ones aren't, leak a bit at the joints, and do skew the o2 readings a bit. Not tuning off o2's, just using them to track trends....

Rock Auto has the weld bungs for real cheap. Forget exactly what it was but I am thinking under $2 each. I would put one on each tube. I started with two O2's and learned they were a huge help. Ended up going to 8 of them. Especially with the mechanical injection it tells you if you get a clogged nozzle or anything is off.

quote:

Originally posted by Curly1:
Rock Auto has the weld bungs for real cheap. Forget exactly what it was but I am thinking under $2 each. I would put one on each tube. I started with two O2's and learned they were a huge help. Ended up going to 8 of them. Especially with the mechanical injection it tells you if you get a clogged nozzle or anything is off.

I'll get to that point eventually I think.....

Why do you ask for others opinion when you already have your mind made up where you are going to place the sensors. There have been more then one reply stating to place the sensor in the primary tube for the best readings.

quote:

Originally posted by S/C718:
Why do you ask for others opinion when you already have your mind made up where you are going to place the sensors. There have been more then one reply stating to place the sensor in the primary tube for the best readings.

you do realize he asked for a opinion on one of two locations? doesn't seem like he had his mind made up, but it does seem that his question was ignored.


Joe

quote:

Originally posted by sr4440:
you do realize he asked for a opinion on one of two locations? doesn't seem like he had his mind made up, but it does seem that his question was ignored.


Joe

This is exactly right...I COULD do them in the primaries but I'm not gonna grind off the coating to weld them in and then have them recoated, especially when the collectors themselves are only painted at this point. Maybe at a later date I'll do additional bungs but for now it's limited to the collectors. I just wanted to know the best location in relation to the merge...

AlkyIROC posted a nice methanol tuning chart years ago.

https://drr.infopop.cc/eve/foru...807026186#2807026186

quote:

Originally posted by 69427:
AlkyIROC posted a nice methanol tuning chart years ago.

https://drr.infopop.cc/eve/foru...807026186#2807026186

I saw that before and printed out a copy....Good reference to use.

The placement of the sensor in an open header will have a drastic impact on the readings...as well as your joints in the tubes that you mentioned. I really didn't think a whole lot about it until I switched over to efi. I originally attempted to run my sensor in the open collector, but that resulted in false readings from the sensor detecting the fresh air from the open collector outlet, which, in turn, resulted in raw fuel being dumped through the injectors because the system interpreted the scenario as being super lean. I had to add header extensions to compensate for this, and have had no issues since then. While this is not the same scenario you are describing, just be aware that the placement WILL make a difference!

quote:

Originally posted by Maxx Levell:
The placement of the sensor in an open header will have a drastic impact on the readings...as well as your joints in the tubes that you mentioned. I really didn't think a whole lot about it until I switched over to efi. I originally attempted to run my sensor in the open collector, but that resulted in false readings from the sensor detecting the fresh air from the open collector outlet, which, in turn, resulted in raw fuel being dumped through the injectors because the system interpreted the scenario as being super lean. I had to add header extensions to compensate for this, and have had no issues since then. While this is not the same scenario you are describing, just be aware that the placement WILL make a difference!

On fuel injection where the sensor is controlling mixture I could see it making the mixture very rich especially at idle. What about at WOT? What is the effect of being near the outlet? I would think there wouldn't be much if any reversion at WOT to pull fresh air back into the collector. So if not FI I would think it would give you a true reading at WOT.

I was able to find a couple of pics showing it installed close to the primaries, just before the merge, so that's where I went with. Was supposed to get both yesterday but found out one had to be made first....hope it gets here before the race on Saturday or I'm putting my old headers back on.

When I put the collectors on, I put a small bead of high temp silicone around the tubes to seal them in the collector. It helps. I'm not tuning off the sensors, just looking to see if my averages are within range...and to track trends....basically gives me direction on tune to a point. Even with a little bit of air leakage at the joints, if I'm lean they will show lean....If I'm rich they will show rich...I watch the plugs much more carefully for actual tuning and cylinder to cylinder stuff....but they do help.