mV A/F compared with wideband?
 

Has anyone compared the Haltech A/F in mV using the 4 wire sensor with a wideband O2 sensor and A/F monitor? I'm interested in what kind of ratios various users are finding in mV relative to Air/Fuel mixtures with a wideband sensor.

For example, 850mV relative to 13.2:1 A/F?

Thanks for the article! Did this article originate in Australia and would the different methods of calculating octane affect the results significantly you think?

Question about the provided article:

The DIY-WB Data refers to 0-5 volts. Haltech measures in 0-1 mV. But why is the curve inverted, is it not? As voltage increases, mixture is lean by the provided WB chart. Haltech reads voltage increase as rich. What am I missing?

I'm not quite sure what your question is since there is no mention of octane in that article. If you are asking about the term "petrol", I assume it to be unleaded pump gas based on the stoich information given. The various grades of unleaded pump gas have basically the same stoich AFR.

Sorry, I thought you were familiar with the narrowband O2 sensor as depicted in the Haltech manual. Anyway, the narrowband O2 sensor operates off a crossing voltage of 0.45 volts, which equates to a 1.0 lambda.

The simple answer to your question is no, you cannot use a wideband O2 sensor with an ECU with a narrowband input because the output graphs are totally different. Compare the LSF 4 and LSU 4 graphs:
http://www.boschusa.com/AutoOrigEqui...odExhSensors/#

Haltech mV to A/F study
 

Well, I'm trying to further my understanding on Haltech's readings so I can tune better and read my datalogs more accurately.

Basically, I'm wondering if anyone has done a comparison with their Haltech using the 4 wire sensor against a wideband system? I'm wanting to find as accurate as I can a model curve for the Haltech showing A/F mixture using the 4 wire sensor.

850mV = xx.xx:1 A/F
etc.

I've seen a couple of people's estimates, but it always seems to be an educated guess. And I'm sure these are based on different factors and/or sensors.

On a side note, the Haltech manual states that a wideband sensor may be used. I wondered about that.

NB sensors are not very accurate at anything further than 1 afr from stoic. Temperature effects, especially on 1 or 2 wire sensors, really take effect.... while 850mV is 13.2:1 at one exhaust temperature, it could be 11.2:1 at a different one, or 13.6:1 - you get the picture. Variances between different sensors of the same model are almost on the same scale of inaccuracy.

4 wire sensors are typically more consistant, but are also more "switch" like, they are just as difficult to read because the AFR will change by large amounts with just a few mV's change in output in the range of AFR that is useful for tuning. Basically they are consistant low resolution sensors.

Ok. Good replies. But we all must have a method or standard for tuning and fine tuning, right? So it's understood that we shouldn't rely solely on the O2 sensor, but it is a guide nonetheless.

Let's start a discussion/poll on what "standards" for tuning Air/Fuel ratios that everyone is using for with their Haltech. What type of O2 sensor are you using? What other factors are observed for proper tuning? Granted there are variances in EGT, environment, and load conditions; what philosophy of tuning A/F are you using to obtain optimum torque, power, and safety, and what are you basing it on?

On my car, using the 4 wire Haltech sensor and under full throttle/boost conditions, the A/F goal has been to maintain 850-950mV. I've found that my Autometer A/F gauge cannot be relied upon for observing lean/rich conditions under full load. Therefore, I monitor the Haltech when I can, and the EGT temps.

Opinions?

Using a narrowband O2 to tune is asking for it.

Most widebands have a narrowband emulation feature.

Ok. I agree that fine tuning should be done with a wideband for best results. There's no mistaking the benefits of such a system. However, I'm still reluctant to view the 4-wire O2 Haltech sensor as completely useless for tuning with it. Nonetheless, I'll play it safe and run more rich based on what I do know until I do become more familiar with exactly what I'm seeing.

I was hoping to spark some discussion from other Haltech users on what they look for in respect to A/F in their own datalogs. The Haltech is far too useful a tool to stick with a conservative map. There are variable conditions that do inevitably change. And of course, this discussion is leaving out ignition entirely, of which must be considered as part of the picture, I know.

Haltech states in the manual that a wideband sensor may be used. Does anyone reading use such a setup?