View Full Version : O2 voltages - narrowband to wideband correlation


jimmyblue
08-16-2004, 10:21 PM
Summary:
Stock(ish) exhaust
910mV = 11.6:1
870mV = 12.7:1

[attached .gif with my two correlation points
superimposed on "standard" O2 volts vs mixture
w/ temp curves]

Narrative (read it before acting on Summary)

I've asked for this a number of times but never got any.
Hoping to be able to tune "good enuf" with the in-car
O2s.

Just got my LM-1 wideband today, and now I can give
my unfortunate narrowband brothers at least one
datapoint. This is for a stock manifolds, gutted cats
car (so front O2s are still pretty much as stock, as
far as the operating environment).

Originally I was tuning for a 910mV target and seeing
900-920mV. I thought this was a good safe place.
Turns out this had me at 11.4-11.7:1 AFR. Oink.

Tonight I edited my PE and OLFA tables until I got it
to a steady 12.6-12.7:1 across the RPM band doing
highway punches. This gave readings of 860-880mV
(call it 870mV, lots of jitter).

I had to pull out 1 degree of spark in the 4000-5000RPM
range to keep from KR. This table had been hand-whittled
to the old AFR range. So there was not a big penalty there.

Sample size of one, make of it what you will. Maybe others
with similar, or differing exhaust configs and some wideband
correlation will chime in.

TT_Vert
08-16-2004, 10:51 PM
notice any performance increases after leaning it out? I have the same deal. I was shooting for .890s-.910s and im at 11.8-12.0 on my LM-1. But, i have cats so who knows what that does lol.>

Dave

HumpinSS
08-17-2004, 07:43 AM
Jimmy are you running in open loop now?

jimmyblue
08-17-2004, 07:46 AM
No, the car is semi-factory-normal, just messing the
mixture & spark around but keeping the closed loop
in idle/cruise. And minus a few little things like cat
honeycomb, rear O2s ignored, etc.

HumpinSS
08-17-2004, 07:55 AM
how are you using the WB and the car staying in closed loop. Are you using the programmable output to feed back to your PCM

Predator
08-17-2004, 08:00 AM
Jimmy, that's been my experience exactly. My O2s are 860/870, and the car makes the most power, according to EASE's DELTORQ, and it feels, without question, SOTP, the fastest, plus no more backfires, very little knock, and insignificant KR (under 1*). I needed to scale my PE vs RPM to maintain 860-870 O2 readings.

deezel
08-17-2004, 08:04 AM
My O2s agree almost exactly with jimmyblue:
910mV = 11.5:1
870mV = 12.7:1

Stock-looking 6.0L truck exhaust (clean cats and holey muffler).
LM-1 mounted in rear O2 port. Rear O2s turned off. WB readings agree before and after "cleaning" my cats.
I think I need to try the open loop excercise to get my VE, PE tables smoothed out. Never enough time...

jimmyblue
08-17-2004, 08:11 AM
how are you using the WB and the car staying in closed loop. Are you using the programmable output to feed back to your PCM

I have a bung in the I-pipe, gutted cats, and the "outer
feedback loop" is me pulling over at the next interchange,
editing the PE/OLFA tables, and getting back on the
Interstate for some more 70-90 kickdown punches.
Closed loop uses the factory front O2s.

Re the Delivered Torque readings - I didn't see any
significant response there. I plotted them last night,
from the different logs I took after changing. But
DT is only a PCM estimate and I don't believe it
comprehends fuel (O2s), just airflow and spark timing
with some fancy calculations based on some factory
assumptions. I should have dug out the old G-meter....

Predator
08-17-2004, 08:23 AM
Jimmy, with the EASE scanner, there is a direct correlation.

jimmyblue
08-17-2004, 10:11 AM
How does the EASE get delivered torque? Is it
a true measure (like crank sensor acceleration
ripple)? Or something like EFILive where it takes
VSS derivative and vehicle weight?

Predator
08-17-2004, 10:57 AM
Jimmy, that's a good question, and it was explained to me but I don't recall, plus I'm not the most technical person. I will have to defer to Team ZR1 for a better explanation (if he's around to respond).

When I bought EASE a couple years ago, a major selling point for me was learning that the deltorq values, unlike competitors, could be relied on for tuning purposes. Team ZR1 has tuned hundreds and hundreds of cars, if not thousands, using data from EASE, without a wideband. And this thread interested me because I arrived at the same conclusions, about narrow-band readings, using just EASE, as you did with your scanner, plus an LM-1.

I can't prove this, but I always suspected that the competitors don't have useful deltorq values because it's good for business to have folks buying dyno time, and lately, purchasing wideband equipment. Heck, lots of sponsors here offer dyno tuning. Imagine if every online here was using EASE, don't you think that would impact tuners and dyno operators? Just a theory. How can I prove it?

HumpinSS
08-17-2004, 11:02 AM
You can prove it by having more that 2 EASE users verify such, but even still you will have a very hard time convincing the masses that a narrow band o2 is just as accurate as a purpose built wideband o2 using a PID that is derived from a mass andacceleration formula

jimmyblue
08-17-2004, 11:34 AM
I know my EFILive has both the Delivered Torque PID,
and a facility to get rear wheel torque / HP by using
the vehicle's mass, acceleration, tire diameter etc.

I thought that there was also a way to get crankshaft
torque, by sensing the acceleration ripple of the crank
sensor (with some fudging for materials constants, the
crank being basically a beam type torque wrench in
motion or something like). But, the DT PIDs have been
explained to me as a more theoretical, calculated from
intake side sensors and mapped to engine torque by
some mystery math, kind of deal.

Would be very interested to know the basis of the
EASE facility - so's I can go badger HPTuners to
provide the same ;)

P Mack
08-17-2004, 12:00 PM
Damn I must be rich as hell at .94. I need that hptuner wideband soon.

Predator
08-17-2004, 12:16 PM
You can prove it by having more that 2 EASE users verify such, but even still you will have a very hard time convincing the masses that a narrow band o2 is just as accurate as a purpose built wideband o2 using a PID that is derived from a mass andacceleration formula

HumpinSS, if Team ZR1 couldn't convince folks, what hope is there for me? And ultimately, it doesn't matter: as long as people are getting good tunes using just EASE, or autotap and widebands meters or dynos, that's all that really matters. The only advantage of EASE is that you don't need wideband equipment or a dyno. And Jimmy's thread really interested me because his findings, using a wideband, matched my findings, exactly, just using EASE. To me, that's proof. As far as anyone else, obviously not. But you know what man, it's all good! You tune your way, and get a good tune; I tune my way, and get a good tune, and we all enjoy driving our cars just the same.

:drive:

jimmyblue
08-17-2004, 02:04 PM
HumpinSS, if Team ZR1 couldn't convince folks, what hope is there for me? And ultimately, it doesn't matter: as long as people are getting good tunes using just EASE, or autotap and widebands meters or dynos, that's all that really matters. The only advantage of EASE is that you don't need wideband equipment or a dyno. And Jimmy's thread really interested me because his findings, using a wideband, matched my findings, exactly, just using EASE. To me, that's proof. As far as anyone else, obviously not. But you know what man, it's all good! You tune your way, and get a good tune; I tune my way, and get a good tune, and we all enjoy driving our cars just the same.

:drive:

I don't need to be convinced (I already have my tools
bought) and I don't care to get into personalities,
but I always like to acquire knowledge.

Predator
08-17-2004, 02:53 PM
I don't need to be convinced (I already have my tools
bought) and I don't care to get into personalities,
but I always like to acquire knowledge.

Exactly Jimmy, that was my point. You've found your method of tuning, and I've found mine, and they both work.

As far as imparting knowledge, I'm sure you know way more about this stuff than me. As far as EASE, I'm just telling you what I've learned, and it's not much use to you except informational, and even then, I don't have the hard technical data you guys love so much. To me, tuning is both an Art and a Science, hard data is important, but you can go a long way with a mixture of some crucial data, and seat-of-the-pants gut level data.

BTW, I digress about a thread in the "Tools" forum, but who knows when I'll have another chance to chat with you, but I took 1/4" and 5/8" ratchets, I had laying around, cut off most of the handles, and now I have two palm-sized ratchets to use for tight places. I think the 1/4" one will work great on those back bolts of the coil packs. :)

jimmyblue
08-19-2004, 08:49 AM
I put my two wideband-narrowband correlation
data points onto an O2 volts/AFR graph I had,
which indicates the 750C EGT curve is roughly
right as a guide for stock-manifolds cars. I
attached this as a .gif, to the original post.