wbO2 vs nbO2 difference in tuning

roro4g63 · Sep 27, 2006, 06:23 PM

Hello, I've recently been tuning my evo with the pocketlogger program. Keep it short, i tuned for .94 on nbO2 and got a good tune with a steady progression through timing (starts 4* thr 17*).

My question is that my innovate lc-1/xd-1 was reading 12.1-12.6 thru those pulls. I immediately started tuning on the wbO2 and got my settings to read 11.4 thru 2400rpm to 7400rpm, with a steady progression with timing. However, upon reading the logs, my narrow band was showing voltage of .96-.98 thru pulls. Weird....anyway ive been tuning off my wbO2.

Just wondering what would cause the difference. wb had been free air calibrated before every tuning runs, and the temp and humidity has been the same on the three nights i was tuning.

Mods: 264/264 cams, 680 injectors, tbe with test pipe, mbc, 255 fuel pump, br lower/upper and air intake. wbO2 is set 6" before where test pipe is (also have h/f cat, just took off).

urBan_dK · Sep 27, 2006, 06:33 PM

I didn't realize there was such a thing as "narrow band o2 tuning"...I usually refer to that as "hope and pray tuning."

But seriously, using the narrow-band for tuning is very risky. You're working with only 1 volt of range rather than a full 5, plus the narrow band is not nearly as precise as a wide band. It's really just useful for computing fuel trims when in closed loop driving, not for tuning.

roro4g63 · Sep 27, 2006, 06:51 PM

not worried about closed loop, thats fine. and yes, nb tuning very bad; however, i did not expect my wb reading and nb reading to be that far off. i am dialing in fuel adj with my wb. i was having a brain fart the first night i was playing with pocketlogger, thot nb and wb would b closer together that. doesn't the ecu dictate fuel map adj. via readings between the front and rear o2?

Just need for my piece of mind...i'm tuning off wb and reading timing/throt pos, to set afc2.

Thanx for the input