DAPSUPRSLO

iTrader: (14)

Is it possible to tune open loop without a wide band by monitoring information from autotap? If so, can you point me in the right direction. If I do this can I scrap my 02 sensors?

Black02SS

iTrader: (36)

I would like some more information on this also.

HumpinSS

iTrader: (1)

Nope the narow bands dont work well outside of the 14.7 ratio. Onl other thing would be to tune through the knock sensors

Team ZR-1

Yes it is quite possible to tune WITHOUT wideband.

All wideband does is it is able to monitor/report over a WIDER AFR range and who really cares if an O2 can read 20:1 AFR ?

A narrow band as we have really only needs to see from about 11 to 15 AFR and the kicker is the PCM ONLY reacts to the O2s ONCE a second for all the PCM has to do is stay within the 1.5 times the EPA's FTP and it meets smog requirements.

900 mVolts is about a 12.4 AFR so who cares about over 1.1 volt.

Riceburners use them cause those popgun engines have to crank out twice the amount of RPMs as a real engine so they of course need to worry more about a wider range of AFR.

Shoot for a 02 reading around that .900 mVolts only as a guage marker but listen to the knock counter and adjust PE timing up or down in the range of 26-28 degrees average if you have stock engine compression and a NA engine.

patSS/00

iTrader: (6)

I think if you calibrated your narrowband sensors against a known accurate wideband, from then on you could just use the narrowband o2 voltage and be pretty accurate. I mean they're probably consistent, you just don't know how far off they are to begin with.

Bill's 02 Z-28 SS

Mr Team ZR-1,
if 900 MV~12.4 then 1.0 V =? and 800 mV =?. Ok we should shoot for 900 mV but was is the big picture? How do you relate 02 read during WOT to AFR?
Thanks
Bill

PS: I want understand the how things work, not just to get a result.

Team ZR-1

800 mV is about a 12.8 and
1 volt is about a flat 12.

Your shooting for about a .880 to maybe .910 depending on the type of gas your using, where as to sealevel and of course if getting knock or not.
I rather be a notch on rich side rather then super lean tripping knock and having timing be yanked back but the real flags via the PCM scanner is how much PE timing and how little knock.
I only use O2 reading during PE or WOT as a guide but really if you command PE such as using a 1.17 value ( in PE table, using LS1edit) you know that is about a 12.5 AFR and tweak from there along with your timing changes.

Bill's 02 Z-28 SS

Mr Team ZR-1,
Thanks - I appreciate the lesson – in order for me to go forward with this tuning, I need the theory behind the changes. Again THANKS
Bill

02RedHawk

iTrader: (17)

Yes, somewhat. But its a blind dart-throw at best.


Anyone who is serious about accurate tuning, that's whom.


Usually I agree with your posts, TeamZR1. But in this case you are very wrong. Stock narrowband sensors are NOT ACCURATE outside of a VERY SMALL A/F range, namely about 14.2:1 up to 15.2:1, give or take a decimal-point or two. It CANNOT, repeat, CANNOT accurately report A/F data at 11:1, 12:1, or 13:1.


No, its not. 900 mv can just as easily be 12.4:1 A/F as it can be 13.1:1. ITS NOT ACCURATE.

Cases in point, I just came back inside from a wideband session on my GTP. Hey, look here... I found a set of datapoints where 905mv = 11.7 A/F.... 910mv = 12.2 A/F.... 895mv = 12.7:1.... Or, here's some data from my latest dyno session on my LS1... 900mv = 12.9:1.... 915mv = 13.2:1.

I confirmed this ~6 years ago on my Syclone with $10k worth of C5R datalogging equipment, confirmed it again last week on the dyno, and confirmed it one more time about 20 minutes ago. There is no correlation between stock narrowband O2 readings and TRUE A/F readings. For this, you *need* a wideband.

What? This is about as bad as a comment a used-car salesman once told me... "This 2.4L DOHC has two overhead cams, so the engine only has to work half as hard." ROTFL! A/F is A/F, regardless of what engine its on, and running rich/lean has nothing to do with how much RPMs you spin.

Finally, something that I will once again agree with you...but only to an extent. Don't worry about "tuning in" your narrowband O2's, and instead focus on your KR readings. You need these to be 0.0 thru all rpm ranges, and adjust PE until you reach that point.

Hope this helps. TeamZR1, sorry bud, no flame intended. But, you were giving out some bad information.

02RedHawk

iTrader: (17)

Nope. See my post above. No correlation can be made, as stock O2s are far too inconsistent at specific A/F's to generate this relationship... It sucks, I know. But, if it really were that "simple", then there'd be no market for widebands....

02RedHawk

iTrader: (17)

WHOAH, NELLY! Slow down there!

I'll give ya another example to illustrate your statement above is wrong.

Just got back from logging my GTP, stock O2 readings were .925-.930v. Guess what A/F I am running?...... <pause>.... 10.6:1 ! ! ! ! !

After some fueling tweaks, my latest runs recorded O2s of .915-.920v, and the wideband gave me an A/F of 11.7:1.

So again, if .925v = 10.6:1 and .920v = 11.7:1, then what narrowband O2 reading equals 11.2:1? .9222222255557281? Of course NOT!

Team ZR-1

No, what your saying is YOU cannot tune using street data from all the functions the PCM reports via OBD-II, many others can.
I hate to tell you but dyno shop widebands are in most cases not calibrated, dirty and in colder exhaust stream on ONLY one side of the engine so its not much better then the narrow band since when tuned off street data your getting 10 miles of data and not 20 seconds where in that time frame the O2 is only reacted on by the PCM 20 times ( once a second)

Simple fact is in almost all cases people find that when they have a best calibration their S1 O2s are between 880 and 920 so there is a common thread in a starting point O2 value to work from for again its knock and timing that dicate what the best AFR is and not some magic AFR value.

Besides that in most cases a car rarely sees true WOT, prove that yourself, go do a normal drive for about 10 miles with a PCM scanner and then see how many PCM cycles have FUEL LEARN Off and how many of those cycles are using cells 15, 22 and above 90% engine load.
Very small percent are.
Its a mute point if you use a wideband and dial in that small percent of engine load on a 20 second static dyno run when simply driving home and using realworld cells will delute that NARROW band tune used on a WIDEBAND O2.

If it was impossible to fully tune using street or track I would not on my own C5 with 11.3:1 compression hit this speed with zero knock and 28 degrees of WOT timing and it was all tuned using the data analyzed from a PCM OBD-II scanner and street runs.



Using mostly any O2 data to tune an engine for all load and engine conditions is the wrong method, its only a guidemark to know if the calibrations were in the right direction, not a stake in the ground.
People drive in the real world, not a dyno, not only at 90% engine load and surely want a tune that conforms to their car's makeup and their driving style and so making a 02 value some magic anchor is not the tuning method I use.

02RedHawk

iTrader: (17)

Its obvious you didn't read a word of my responses.

As I stated, I have in fact TWO widebands I use at home here (not on the dyno as you are trying to use as a counterpoint), a 3rd wideband set of data from the dyno-shop, and a 4th & 5th set of older wideband data from my Syclone/C5R tuning days back in '97 or so. Bailey, NTK, Bosch - IT DOESN'T MATTER - they all showed the same non-relationship. Still don't believe the truth? Since you're into 'Vettes, perhaps you know some of the C5R expert data-acquisition team members. Go look up Frank Parker, chief data consultant for the team. Ask him if there is a correlation or not. Oh, and tell him that Mike says hi!

THERE IS NO CORRELATION BETWEEN NARROWBAND O2 READINGS AND WIDEBAND READINGS. IT IS A FACT.

XLR8NSS

iTrader: (4)

People are gonna be blowing there cars up going by .800mV = 12.8 and some of the other stuff listed here.

1V = 12 flat

Unless you have correlated your stock 02s with a wideband and have made no changes since doing so DO NOT USE THEM TO TRY AND TUNE OPEN LOOP!! I still wouldn't anyway.

I have a wideband sensor and .960 on my stock 02s is ~10.5:1 AFR. .900-910mV is around 13:1 AFR. This is on MY vehicle and those numbers will not be the same as someone else with a different setup.(these numbers are close but, it's been a while since I checked)

Please guys if you are into this serious enough to want to tune open loop do it the right way with a good wideband setup.

parish8

iTrader: (6)

i'm with stupid , get a wideband, they are prety reasonable these days.

XLR8NSS

iTrader: (4)

Much more reasonable than having to buy a new engine.

Team ZR-1

ooh I have read what you posted and again, your concept says you cannot tune UNLESS you have a wideband which is not true and all this does is confuses a ton of people who bought a tuning product who then are told they cannot properly tune unless they also spend money on a wideband or the cyberspace myth a tune can only be done on a static dyno.
That is your method fine, but I have tuned 100's of cars that were 1st dyno tuned with a wideband and end result is they came to me for a true custom tune without the WB, so something says the WB theory does not hold water.

I find it interesting that I can hand tune without one, and then go on a dyno and the AFR is exactly what I tuned the PCM to.

Lastly, there is zero fact showing these cars make a bit of rear wheel HP increase on the street if the final AFR is a 12.4 or a 12.8 for again my point is having a so called perfect magical AFR for WOT is washed out with the real world of all the other driving conditions mixed in thus the PCM commands a 14.6 AFR most of the time and about a mid 12 ( if PE table is set for that) and in the end no magic AFR from a wideband has any better overall results as hand tuning from analyzing ALL the PCM functions and tuning off that data.

So in the end we can get just as good or better overall tune then spending a bunch of money and time on a wideband while your chasing you tail on some perfect AFR that does not happen in street or track driving.

02RedHawk

iTrader: (17)

TeamZR-1. Its evident that you are incredibly close-minded on this subject, and unfortunately not very versed on it either. For the third time, I tune on the street, not the dyno. Widebands were made for a purpose, one that for some reason you just refuse to accept.

Have fun "tuning" in the dark. Good luck with that.

Brains

iTrader: (7)

Folks, JR doesn't understand that others may know more than him about something. He'll argue his "point" until you either believe him (unlikely) or you walk off shaking your head realizing you can't teach the unwilling. Anyone remember the LS1Edit mailing list fiascos?

Either way, I would personally recommend *NOT* following anyone's advice if they're trying to tell you how to tune your vehicle in open loop using a narrow-band oxygen sensor. Its insane to even try, unless you're *ONLY* trying to get to ~14.7:1 AFR ..

Here, JR won't believe this because... well, he just won't Look how accurate your narrow band would be outside the very .. .uhh.. narrow range centered around 14.7'ish:

J-Rod

Possible, but not recommended. Its possible to tune a car with no data whatsoever on it, your results may very though...

Right and wrong. Yes a WB measures A/F ACCURATELY over a wider range than a convetional o2 which is only good around stoich where it ossiclates (switches) rapidly. Other than that, its not what I would call super accurate. Not can all 02 readings be considered gospel. (I.E. .880-.890 is perfect A/F)

A 1V switching O2 sensor signals "Lean" whenever the voltage is less than 450mV and "Rich" whenever the voltage is above 450mV. It will never provide an actual 450mV unless it's dead, in which case you're seeing the 450mV bias voltage supplied by the ECU to detect this situation. One cannot, in general, assign any particular A/F ratio to some voltage reading from the sensor. On one new sensor, 800mV might actually correspond to 14.0:1 A/F ratio but, on another identical new sensor from the same manufacturer, 800mV might correspond to 13.0:1 A/F ratio. This is because manufacturers (and ECMs) don't care what happens in the "tails." All they care about is that there exists an abrupt and significant voltage change when passing through stoichiometric that is centered on 450mV. Even for a given sensor, 800mV can mean different A/F ratios, depending on when the measurement is taken, because the shape of the "tails" is affected by both temperature and pressure.

The only exception to the above that I'm aware of is the Bosch LSM-11 O2 sensor, which was designed for use in A/F analyzers. Bosch engineers have developed precise response curves for this sensor as well as temperature and pressure correction tables and each sensor is checked at the factory to insure it conforms. Of course you'll need a few thousand dollars to buy such an analyzer (e.g ETAS LA-2).

The bottom line with 1V switching O2 sensors is that you only need two lights, one for Rich (i.e. above 450mV) and one for Lean (below 450mV). Attaching any other meaning to the sensor's voltage level is a fool's errand.


Maybe on one car, but maybe not on another...

That is the most ridiculous comment I have ever seen with regards to an 02 sensor. Would you apply the same logic to the new C6 which is shipping with WB from the factory? Its going to rev more than an Ls1 so its needs a "wider" sensor...

Go buy a wideband, or go to the DIY WB o2 site... http://www.diy-wb.com