smokeshow

iTrader: (16)

I wouldn't bother putting any effort into the VE table in open loop where closed loop would otherwise be active unless you intend to disable closed loop entirely. As Atomic said, you're better off trusting the narrowbands in that area. If you recalibrated the entire VE surface in open loop just using the wideband, you're guaranteed to have a noticeable difference in the fuel trims. The control strategy for O2 sensors that interface with the PCM is very different from your conventional 'wire it in' style wideband sensor. Onboard narrowband sensors will account for changes in exhaust pressure and other variations that an Innovate or Autometer sensor cannot.

STFTs are great for every application that doesn't idle within 10kpa of barometric pressure. LTFTs could only really be used if the wideband sensor signal is characterized the same way the narrowbands are, starting with matching AFR readings for the entire steady state closed loop realm...even then, I don't think I'd put my complete trust in it. However I've never seen a properly calibrated aftermarket wideband match the narrowbands exactly... So in order to prevent the 12% discrepancy you'll need to adjust the wideband AFR error calculation accordingly with some 'lambda normalization'. If we're assuming the narrowbands are more accurate (I do), then you can employ a method to account for the disagreement between wideband and narrowband. If you're curious and comfortable using Excel, I can write up the procedure.