For those of you who run the dual O2 sensors (one per engine side), how close are you getting your WOT A/F readings from one side to the other?

I am currenty reading .4 difference from the drivers side to the passenger side with a RPM dual plane intake. After some stagger jetting on the secondary jets, I have closed up this spread from .8 to .4 from one side of the engine to the other.
How close do you try to tune your A/F readings from one side to the other at WOT?

Thanks allot!!

I`m curious too. I plan on doing this in the 68`.

Heck iam still tring to get the idle and part throttle A/F where I want it. At the track the car always likes more jet.
I cannot get my FAST A/F meter to record and I sure am not going to take my eyes off the track to look at the sceen.

Be careful. I had my truck 440 on my dyno with e.g.t's hooked to each header tube. RPM intake. A couple of cylinders had much higher temps and the plug readings confirmed those cylinders were lean.
You have to adjust things so that the leanest cylinder is safe. If you go overboard,you may get a cylinder too lean and hurt something. Thats the bad thing about tuning with 02's in a collector. You can get a safe reading and still have a lean cylinder.
Learning to read plugs is always a good idea.
Keith

I'd suggest swapping over to a single plane intake just so you get some data both ways. If this is a big block engine then it only takes a short time to swap intakes. If the readings change a bunch then you know it was the intake. If they don't, then either the carb is wrong, or something is going on with the exhaust system.

Andy made a good point,
I have seen some different headers on the same engine make big changes on cylinder to cylinder readings.
Keith

The first thing I would try is swap the plugs on the A/F meter (side to side)to see if there is any difference there then I would swap the O2 sensors themselves from side to side & see how things look, then go back to the carb.

My passenger side was showing richer on the O2 gage so I pulled the plugs and they confirmed that side was definately richer. I know what my safe limit is on my WOT reading, now I am trying to determine how close I can get each side to each other with a dual plane intake on my sb. Is .4 good to you racers or do you like to see both sides a little closer to each other than that?

Thanks for the replies.

""OP, it wouldn't suprise me that you may need to have staggered jetting on the primary side of the carb also with the dual plane intake Don't be afraid to experiment and learn some more""

I made another secondary jet change this morning which staggers the rear side to side by 6 jets. I should be able to test it later on today.
I am trying to stay away from staggering the primary side since my A/F numbers up to 3500rpms are within .2-.3 from side to side. I have thought about staggering the pvcr's though if the secondary jetting gets out of hand.
Thanks CAB

Back to the original question. How close are you guys trying to get from one side of the motor to the other at the end of the track?

Thanks to all!!

In all honsety,don't try too hard to get ideal numbers with your meter. From my experience,there will be a need to do some work on the intake to equalize mixtures from cylinder to cylinder. Then staggered jetting can help a little. When you stagger jetting,you affect more than one cylinder. You may get one too lean trying to get another one ideal.
Basicly,don't drive yourself nuts trying to get things perfect. If you don't work on each cylinder individually working with egt's or O2 sensors in each pipe,you will never get each cylinder perfect. SO there will most likely be a difference from side to side. The amount of difference depends on too many factors to give a generic number.
Keith

Thank you Keith!!

No races today, it was called off after a incident that occurred at the track last night. As far as how close on the dual wide bans I reviewed all the runs I had stored on my lap top last night and it seems there is a difference from side to side, mine may be caused by the potential leak at the collectors and tail pipe joint Look at all the plugs,tune off of them The time slip and spark plugs will never lie to you

I tested a six jet stagger in the rear of the carb with the leaner jet on the passenger side. Since this is a street car, I made three test runs from a 50mph cruise to WOT shift point. All three times each sensor read 0 or .2 different from the other sensor. I went from a .5/.6 difference per side when jetted evenly in the rear to tonight's 0/.2 difference with a six jet stagger.
Note: My primaries stayed even.

I'm happy with that!!

Thanks for the up date,I will have to try that.

Did you notice a seat of the pants difference after the change? Do you have any desire to run your car on the quarter mile to baseline performance?

Before I staggered the jetting, the performance at the WOT was lazy especially when the hotter Summer air set in. Then when I noticed the A/F difference in the sensors, I figured that is was just too rich for my combo. If I leaned out both rear jets at the same time, then I lost power and I got detonation at WOT. Then when I jetted back up, there was no detonation but the performance was down. So once I leaned out the side that was rich, the seat of the pants performance came back. I was very happy with the reaction of the car.
I am not close enough to a track to do any testing. My car is a street car and fortunately I have some areas that I can hit WOT without bothering others for my testing.
I have not done an idle to WOT (shift point) test but maybe in the near future I can try that out.