Aftermarket Wideband to Rear O2 signal

[tomm.brz]

What i do not understand is which front scaling to use.
There is the stock front scaling, the ots front scaling, the ztan front scaling and ecutek front scaling.. All different.
I use ecutek front scaling that is quite offset from the others and my 12.3 afr with that scaling, it s more like a 11.9 afr with ots front scaling

How do one choose the best one? And how do one do a correct scaling for a wideband aftermarket sensor?

[Kodename47]

Originally Posted by Tor

If it's consistently reading inaccurate, does it really matter? Say, it's always reading 12 when the WB at the tail reads 11.5.

This I agree with. The key is the optimum of power and knock resistance. The rest in largely irrelevant.

Originally Posted by Tor

How much variance did you see? It would also be interesting if the variance is the same between different cars (canned tunes).

On a SC car the readings become increasingly skewed at higher RPM. Even if the input AFRs are the same and the tailpipe WBO2s also show the same. Probably less of an issue on an NA car. I remember that EcuTek verified a WBO2 against the OEM sensor, it's in their docs. Someone else said that theirs ran well on it, mine was 1 AFR or so leaner for the majority of the powerband. I also ran mine on a leaner scale than ztan's, the one that everyone uses. I did it so that it would read leaner so I would essentially tune it a little rich. It was still too lean at the tailpipe. So now mine is my own scale correlated to my findings on a dyno I trust giving me AFR values that I know work. Before anyone comments I know that the tailpipe sensor will read leaner by nature, but we expect in the region of 0.1-0.2. This is largely irrelevant however as on the dyno we can tune for the optimum without actually needing a set target/matching AFR and the AFR output is more an understanding of what's happening.

[Kodename47]

Originally Posted by tomm.brz

What i do not understand is which front scaling to use.

Pick one and run with it. Unless you can verify/prove then just stick with one you know. That way you can verify any changes you make. I spent too long worrying about it to realise that it doesn't matter. AFR tuning is best fit, not a definitive answer. All you really need to know is too lean/too rich/in the ballpark. Unless you hit a dyno, then you can't fine tune enough to tell the difference.

Originally Posted by tomm.brz

How do one choose the best one? And how do one do a correct scaling for a wideband aftermarket sensor?

WBO2 is a custom input and not a replacement of the OEM. Most aftermarket ones have a 0-5v output that is linear to the reading so really simple to map in.

[Tor]

Originally Posted by Kodename47

Unless you hit a dyno, then you can't fine tune enough to tell the difference.

Add to that, even with a dyno, you will have a hard time tuning for the actual conditions your engine will see in real life.

Tuning to the tenths of AFR to get most power on a dyno only to have it retard timing once you take it on track/street/whatever-kind-of-driving-you-do seems like a bit waste of time in any case. I'd say tune for least FLKC instead.

Rather run too rich and with little FLKC than the otherway around. Because you can for sure feel the ECU taking out 3-5 deg timing!

From personal experience, going up Kesselchen on the Nordschleife (max gradient over 10%) in 4th and 5th gear the car feels very powerful with max timing and 11.1 AFR and like the engine is only running on 3 cylinders with 12 AFR and -5 deg FLKC.

I'm not saying everyone should target AFR 11.1. That's just what works for me. Tune ignition timing with a reasonable AFR (12ish) under moderate conditions (e.g. do 5 back to back 3rd gear pulls) and make sure it's relative knock free. Then take it to the most extreme conditions that is in your driving profile and if it knocks lower AFR before reducing ignition timing.

At least that method works for me.

[Kodename47]

Originally Posted by Tor

Add to that, even with a dyno, you will have a hard time tuning for the actual conditions your engine will see in real life.

Tuning to the tenths of AFR to get most power on a dyno only to have it retard timing once you take it on track/street/whatever-kind-of-driving-you-do seems like a bit waste of time in any case. I'd say tune for least FLKC instead.

There is a definite AFR band for making power, at least on the boosted cars, even without any knock corrections. Hence my comments about knowing what ballpark you want rather than making sure you're hitting within 0.1 of target IMO you want as lean as possible in that band for day to day as not wasting fuel but enough to stop knock corrections. But you're correct that a few degrees of timing loss costs more power than a slightly richer AFR. Whenever I've been on the hub dyno we run 5th gear and 10-12 second ramps which would roughly simulate a decent 4th/5th gear pull on the street IMO. Certainly for AFR tuning it's as good as you can realistically get.

[steve99]

Most guys get tuner to tune car using tuners tailpipe wideband.


When they install failsafe wideband it usualky just to save motor if it runs way lean so doesnt need to be super accurate for failsafe function just consistent . Just pointing out you could do that with stock sensor rarther than jnstalling separate sensor and wiring.


I would also assume ecutek would have warned tuners not to use the stock sensor for full time closed loop fueling in racerom 10 if the stock sensor was not accurate or consistent enough ?

[Xero-Limit]

Originally Posted by steve99

Most guys get tuner to tune car using tuners tailpipe wideband.


When they install failsafe wideband it usualky just to save motor if it runs way lean so doesnt need to be super accurate for failsafe function just consistent . Just pointing out you could do that with stock sensor rarther than jnstalling separate sensor and wiring.


I would also assume ecutek would have warned tuners not to use the stock sensor for full time closed loop fueling in racerom 10 if the stock sensor was not accurate or consistent enough ?

I've found many dyno wbo2s to be terribly inaccurate. Those systems are very expensive and few dyno operators want to spend the cash to get them regularly calibrated which they frequently require. Combined with the fact that they sit in the tailpipe, you get post cat readings and fresh air mixing in, which leads to lousy readings.

The factory sensor is useful to the low 12's, you can stretch the calibration to high 11's but it isn't terribly accurate there. I wouldn't use closed loop fueling with a factory wideband even with the stretched calibration.

[steve99]

Originally Posted by moto-mike

I've found many dyno wbo2s to be terribly inaccurate. Those systems are very expensive and few dyno operators want to spend the cash to get them regularly calibrated which they frequently require. Combined with the fact that they sit in the tailpipe, you get post cat readings and fresh air mixing in, which leads to lousy readings.

The factory sensor is useful to the low 12's, you can stretch the calibration to high 11's but it isn't terribly accurate there. I wouldn't use closed loop fueling with a factory wideband even with the stretched calibration.

even on NA car ??

[Xero-Limit]

Originally Posted by steve99

even on NA car ??

It's more doable with NA, but what makes it less ideal is that once the reading goes below 12, as you won't know how much fuel to remove to achieve a 12.7 or 13 or whatever you're aiming for. You could do it in small steps though.

[airrick]

Necro.

So i connect the pin 20 on A35 and pin uhh. Yea im pretty confused on the wiring. The pics would help.

[airrick]

Originally Posted by welllam

The solution was to settle in with the current conditions, download Failsafe and AEMdata software and find out the difference between display value and logged value mostly targeting the red line area. Then work with your tuner to adjust the difference with some mathematical formula. I worked in this way with motoeast Mike.

I have wired up my wideband to ecutek via the evap (CPC). My gauge and ecutek differ a bit. At first it seemed to be consistent .5 or .75. Now its just fluctuating a bit more. Sometims gauge shows 16.75. Ecutek shows 15.82. I have the AEM 30-0300 wideband

And everyone is getting the voltage the 4.5v or 4.12v etc.. i am getting 3.49v maximum and minimum of like 3.48v. I’m not very good at electrical stuff. Could someone with some insight. Im thinking i did something wrong wiring it up. I moved the ground thinking it was a bad ground location but same result.

[Kodename47]

Originally Posted by airrick

I have wired up my wideband to ecutek via the evap (CPC). My gauge and ecutek differ a bit. At first it seemed to be consistent .5 or .75. Now its just fluctuating a bit more. Sometims gauge shows 16.75. Ecutek shows 15.82. I have the AEM 30-0300 wideband

And everyone is getting the voltage the 4.5v or 4.12v etc.. i am getting 3.49v maximum and minimum of like 3.48v. I’m not very good at electrical stuff. Could someone with some insight. Im thinking i did something wrong wiring it up. I moved the ground thinking it was a bad ground location but same result.

What EcuTek AFR output are you logging? Has the map been setup for this WB?

[tomm.brz]

YOu probably have given a bad ground connection to the gauge and to the 0-5v output
they need to share same ground locationn, and set the scaling as per AEM spec
you ll have then a good coherent signal in both gauge and output, i have same gauge and my WB signal works good

[airrick]

Originally Posted by Kodename47

What EcuTek AFR output are you logging? Has the map been setup for this WB?

I am logging it under AFR - Wideband in ecutek. Yes, my tuner scaled the map. Now it the difference from the gauge and ecutek is about .3. I was just going to have my tuner scale it precisely .3 higher to match my gauge.

Originally Posted by tomm.brz

YOu probably have given a bad ground connection to the gauge and to the 0-5v output
they need to share same ground locationn, and set the scaling as per AEM spec
you ll have then a good coherent signal in both gauge and output, i have same gauge and my WB signal works good

hmm, thats what i thought as well. I have moved the grounds and still shows that it only gets 3.49v max. Yes they are at the same ground location. My tune was scaled per AEM specs. But now it shows about .3 lower on ecutek so i might just ask my tuner to change the ecutek WB to read .3 higher match the gauge. Your gauge and ecutek afr number are the same? Where are your grounds located at?

I have all my grounds for all my gauges located on a bolt under the steering wheel. This bolt in the pict.