Terminator X with only one O2 sensor?

[brickyard69]

My new LS3 crate motor came with a Holley Terminator X system. I am puzzled that it only has one O2 sensor. Is this correct? Shouldn’t it have one for each side? Does it matter which side of the exhaust I use?

[dontlifttoshift]

One O2 is fine. I put a bung in each exhaust pipe. If the car ever goes on a dyno they will want to hook up their own wideband. If you ever have a problem it can be helpful to swap the O2 from side to side. If you want to be really fancy you run the car and leave the O2 on which ever bank tends to run leaner.

[65 drop top]

If I recall correctly, you can add a 2nd O2 to one of the terminator inputs (must be X/X max) but it will be limited in what it can do. Something like it can not run closed loop based off of the 2nd O2, so the 2nd O2 is there just to monitor, not run the engine. But I’m basically efi illiterate, so hopefully someone in the know can confirm what I’m saying.

[andrewb70]

My new LS3 crate motor came with a Holley Terminator X system. I am puzzled that it only has one O2 sensor. Is this correct? Shouldn’t it have one for each side? Does it matter which side of the exhaust I use?

The Terminator X (and X Max) ECUs only have one wideband O2 sensor. You can install it in either bank. If I can be of service with the tuning or other questions, please email me: projectgattago at gmail dot com

Andrew

[sccacuda]

This is one limitation across the Holley ECU line up. Even if you add the second O2, the ECU strategy does not allow independent cylinder bank trim. Your options are, left only, right only, average (of two sensors), richest, or leanest. The important thing on setting up the software is limiting fuel trim corrections, especially at high load WOT. Once tuned, I don't recommend allowing negative fuel trim to be more than a few percent, depending on the combo, and at WOT, I don't allow any negative fuel trim.