Who do you trust (most)???

[SideStep]

Who do you trust (most) when SD tuning your VE table, WideBand or STFT (or maybe a blend of both)???

Mods in sig (small 2002 ZO6 cam)

[Russ K]

Wideband, no question. The STFT's take time to respond, and they are always moving around even when the LTFT is learned at a steady rpm/load.

Russ Kemp

[Bill@HPTuners]

wideband and good data

[SideStep]

Wideband, no question. The STFT's take time to respond, and they are always moving around even when the LTFT is learned at a steady rpm/load.

Russ Kemp

I have disabled the LTFTs (and DFCO) for this experiment... so no LTFT learning. The reason I am asking is my STFTs do not agree with my WB.. specifically at low rpm, low MAP areas...

[jimmyblue]

Have you realigned your FTC boundaries to segregate the sub-
cruise MAP/RPM from cruise / accel and so on? STFTs will be
as unreliable as the NBO2s' operation at low gas flows. And
any issues you have with minimum pulse injector delivery will
also taint the learning (subtract all you want, min pulse is min
pulse).

I tried to set mine so lowest MAP boundary is just above idle
and all bins are in by 4000RPM. For a car that idles higher MAP
than it cruises, you might rethink the MAP boundaries.

Ideally you'd get to where crappy O2 response only buggers
one or two cells and the rest are clean, and useful.

[WS6FirebirdTA00]

wideband and good data

[EC_Tune]

Wideband is always the most accurate. However, you will be running on the stock O2's so get everything dialed in and then check against the stock o2's as a double check.

BTW: The stock o2's for some reason run the AFR a bit on the leaner side of stoch in virtually all the cars I have tested. I think there may be a doping issue with the stock o2's but at this point it's just speculation.

[SideStep]

Wideband is always the most accurate. However, you will be running on the stock O2's so get everything dialed in and then check against the stock o2's as a double check.

BTW: The stock o2's for some reason run the AFR a bit on the leaner side of stoch in virtually all the cars I have tested. I think there may be a doping issue with the stock o2's but at this point it's just speculation.

This is exactly what I am seeing. I guess the two (NB and WB) are never going to agree to the level of precision I want...

[12secSS]

I always trust the wideband! I have experienced that some vehicles will run leaner based off of the Fuel Trims (-3% to -6%), although my truck (1500HD) has pretty much all the Fuel Trims all in the +/-1% range. Although trucks run on 14.681 stoich and have the O2 switch points at .481 volts. Where as cars are at 14.62587 and have switch points ranging from .38x to .43x, so this could be the culprit. But the NBO2s do not have good resolution to distinguish this kind of variance.

[EC_Tune]

Trust your wideband to get the VE & MAF right and then let the narrows do their thing. At light to medium throttle it will be a fuel economy benefit to be slightly higher than stoch anyway.