O2's in collectors
 

I just read in another thread that the O2's should be 18" from the end to avoid miss readings because they are too close to normal atmosphere. I just welded bungs in my merge collectors and because the entire unit is so short there is no way I'm any where close to 18". Question is...... what I can I expect, is this workable or do I need to add on the end to get " true " readings even though it may very well cost some power.

Re: O2's in collectors
 

You will see lean spikes at rpm below about 5000....

I had an O2 recorder on my Firebird LT-1 stocker and had the sensor in the collector......I added some length to it and it was better but still some very lean false readings....

It was still usable using the "smoothing" feature of that recorder to dampen the spikes......

Re: O2's in collectors
 

The low RPM readings will not be accurate. As Rich said use a collector extension for a more accurate reading. For idling in the pits we made a 12 inch collector to adjust the air fuel ratio.

Kirk

Re: O2's in collectors
 

under full throttle (2 step,leave ,pull thru the gears) your o2's will read .50-.75 leaner than if you had a full exhaust,, I am 12.5 - 13.0 between the left and right side banks ,now if I moved the o2 up to the primary tubes it will be richer but only measure that one tube ,but it will be more of accurate #,, so its a test and tune deal ,,you have to dial your et vs you afr = et and mph ,yeah 12.5 is your target but its subject to how your combo reacts (that my take on my set up)
tom goldman has some experience in this wheel house

Re: O2's in collectors
 

If your collectors slide on to the primary tubes , you might get a lot of air coming through the gaps . That really messes up the readings at all rpms .

Re: O2's in collectors
 

OK: Thanks for the replies.

Re: O2's in collectors
 

For those that may have the slip-on collectors and wish to install an O2 sensor in them, what is the consensus on sealing the collectors to the primary tubes with an extreme high temperature sealant, such as this:

https://www.fluidsealingsupply.com/d...RoC5JoQAvD_BwE

I'm guessing that one downside would be that the slip-on collectors would then be much harder to install or remove from the primaries.

Re: O2's in collectors
 

All good information above but what I was told to be more concerned with getting it in the proper position behind the merge 6 to 8" would be much more important.

Re: O2's in collectors
 

does the # matter that much as long as its consistent enough to see change once you know what the engine likes you can adjust to that. i always think of it as a tool to better understand how changes and weather effect the car and not to chase a magic #

Re: O2's in collectors
 

Put the O2 in a primary tube and it works great all the time except if there is an issue with that cylinder. I originally had mine in a collector and continually fought it. Moved it to a primary a couple years ago and never have a problem.