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Jeremy Towers

Wideband Lag

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I have been pretty successful tuning my engine with a Wideband O2 sensor and data logging on the G4. No Dyno

There is one hitch though that messes up my logged results. That is LAG from the wideband sensor.

Is there any provision for entering Wideband sensor Delay when analysing data? Even a single delay time entry would improve accuracy a lot for road or track tuning. A 3D table would be awesome.

Maybe it is possible now to edit the log file in Excel by shifting all the Wideband data by the delay time, then loading it back into PCLink? But that sounds like hard work.

I know the Vipec guys use 'Mixture Map' and I am sure a method of correcting the errors from wideband delay would make that tuning tool WAY more accurate.

Your thoughts or suggestions please.

Jeremy

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Hi Jeremy,

While this sounds like a useful suggestion, there is a slight technicality for most users:

Do you know the actual delay from the exhaust port to the sensor plus the response time of the sensor and controller, plus the filtering of the analog input signal?  Without this exact information, you would be risking making your tuning information less accurate by entering in an incorrect delay.  Furthermore, this response time varies depending on the average exhaust velocity (ie engine RPM/load) and also on the rate of change of AFR.

On a high quality wideband controller located close to the exhaust under high flow conditions, it is usually considered to have a response time that nears the typical sample rates used for AFR measurement (eg 20 to 50 Hz).

Regards

Ashley

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Hi Ashley

I hear what you are saying, but I still think it's a good idea. A lot of other functions in your PCLink/ECU also require a higher level of understanding, but not all users have to implement them.

Most high performance V8 engines have the O2 sensors at the collectors. That is some distance from the engine, so O2 data is always delayed. As far as 'actual' delay goes, I can see and measure the delay in mS between a throttle position change and an O2 response in the logged data. It is just frustrating that I can't compensate for it!

Jeremy

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