I'm not 100% positive this is the right forum for this question but as near as I can tell it should still be. I'm planning to find a shop tomorrow to weld a bung into a header for my wife's 2002 Sunfire (2200 OHV). My question is, where should it be welded? To throw a slight wrench in the works, it's a 4-2-1 header although I'm mainly just interested in which cylinder tends to run the leanest/hottest and therefore what we should be monitoring with the wideband O2.



As you can see from that photo the bung already welded in is in the front Y (which comes from the middle two cylinders). Should we just have another one put on the opposite side but in pretty much the same location? Or should it be further up on an individual runner, or even perhaps on either the left-most or right-most one (the Y in the back).

My feeling is that ideally it probably should only be monitoring one runner, the leanest one. What it boils down to is, which one is that?



Also, somewhat related, from the location of the O2 bung already on the header, does it look as though the wires will have to be extended or not? I haven't really ever looked at the O2 sensor's stock location and how much wire there is. If it needs wiring, is that simply a matter of cutting the wire and splicing a length of added wire in...and what gauge wire should be used for extending an O2?

Put it where all 4 come into 1.

Uhh, that's at least 24" downstream, just looking at the header. And what does that do to you if one cylinder tends to run leaner than the others? They're going to average each other out by that point and you're going to see just that, an average. I'd think it quite possible that one cylinder could be at 13.5:1 at WOT and another, for some reason, could be well over 14:1. I'm looking for which cylinder would typically run the leanest so we can monitor that one.

Unless on the OHV the 4 cylinders tend to run perfectly even across the board. I know on my car (2001 Eclipse GT, V6), the front bank middle cylinder is widely known to lean out much much more than any other on the car. I figured there was something similar on these engines, but perhaps not...

Although thinking about it further, I can see putting a bung where all 4 come together, for one reason - to put the stock front O2 sensor there so that it can read that "average," and then put the wideband in the bung that's already on the header to begin with. After all, the odds of leaning anything out at part throttle enough to blow an engine are pretty much 0. However, what I'm still looking for is someone who can confirm the leanest cylinder on the 2200 OHV...if again there is a distinct one.

well one way is to put fresh spark plugs in go out and run it hard go home and pull the plugs....... look at them and determine which one would be the leanest

Cylinder 3 is usually a common place for honda's and 4g63 cars. i've heard other guys have tapped 3-4 inches off the manifold flange on cylinder 1 too...


1996 Z24

Z Speed Cavi wrote:well one way is to put fresh spark plugs in go out and run it hard go home and pull the plugs....... look at them and determine which one would be the leanest

That's a very good idea, I never really thought about that. Course you'd probably have to run it hard for a pretty good amount of time to get the plugs to a point where you'd see any kind of noticeable difference, but yeah, that should work. Only problem I can see is that her car ran pig rich on the dyno for the baseline run (somewhere around 11:1 at WOT) so I'll bet all 4 plugs would just turn black as hell

L1NGL1NG wrote:Cylinder 3 is usually a common place for honda's and 4g63 cars. i've heard other guys have tapped 3-4 inches off the manifold flange on cylinder 1 too...

Thats for EGT, widebands, if you read the instructions, are supposed to be at LEAST 24-36" from the head and in the COLLECTOR or pipe with all exhaust streams in it.





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Why wouls you ever want to read just one cylinder? thats just crazy! That would mean serious people would run 4 o2 sensors and nobody can ever say they have seen that.
The average is what you want, definetly. between the wiseband and an EGT nothing will get by without being detected, even a single cylinder problem.
Have fun installing gauges man!

Joshua Dearman wrote:Why wouls you ever want to read just one cylinder? thats just crazy! That would mean serious people would run 4 o2 sensors and nobody can ever say they have seen that.
The average is what you want, definetly. between the wiseband and an EGT nothing will get by without being detected, even a single cylinder problem.
Have fun installing gauges man!

actually i have done it. It was an old Chrysler Slant Six that i did a megasquirt EFI on and a turbo running 11psi of boost made close to 350hp to the wheels. Did 6 Wide band 02's in the header to tune AFR's individually. Not something i would do again as it was sensless, all of the cylenders were close, had to adjust a few settings here/there but other than that it was all good.




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wow, your the first I've ever heard of and hopefully the last

I've heard of two in alot of modified cars but not more than that!


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Bballjamal (Cav-AtL) wrote:I've heard of two in alot of modified cars but not more than that!

Yeah it seems to me that two of them on a V6/V8 would be fairly logical honestly, but we're only going to be using one

Shifted wrote:

L1NGL1NG wrote:Cylinder 3 is usually a common place for honda's and 4g63 cars. i've heard other guys have tapped 3-4 inches off the manifold flange on cylinder 1 too...

Thats for EGT, widebands, if you read the instructions, are supposed to be at LEAST 24-36" from the head and in the COLLECTOR or pipe with all exhaust streams in it.

x2

put it in the single pipe after the last 2-1 section , and it has to be in the upper 180 degree of the pipe , and make sure its not hitting any where