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Wideband O2 sensor positioning
peterwub - 19/6/11 at 09:43 AM

My first question here...

I am currently converting my 1700 x-flow to bike throttle bodies with Megasquirt II. The project is nearly complete and I'd like to add the Innovate LC -1 O2 sensor. The positioning could be an issue as I have a 4𣇻 manifold with the 2 branches exiting the side of the car. Therefore to mount the sensor after the 2-1 collector would look ugly and leave the sensor exposed. Ideally, I抎 mount the sensor in one of the 2 branches inside the engine bay so it would be in the exhaust stream of cylinders 1 and 4 or 2 and 3. Can anyone tell me if the sensor would work properly when reading only two cylinders?


Pete


trikerneil - 19/6/11 at 11:05 AM

Hi Pete and welcome.

Seems to me that you would only be measuring the exhaust gas from two cylinders and trusting that the other two were somewhere handy. The settings from the Megasquirt are obviously applied to all four cylinders the differences being in the tolerancing of injectors etc.
To get a true picture you either need to put the sensor in the last pipe or get another sensor.

Having said that you only get an average of the four exhaust streams with the sensor in the last pipe so would the average of two be any less informative? You could fit two bungs, swap the sensor between them and compare the outputs from the two branches to prove the point.

HTH

Neil


mark chandler - 19/6/11 at 04:22 PM

Unfortunately asthetics and lambda position do not go hand in hand, it needs to go into the last collector or pipe soon after this.

If you do not like the look then I suggest that you purchase a stainless steel bung, map the car and when its going well turn off auto correction and unplug the sensor.

It also needs to pop in the top really so it does not get washed in condensation as this will ruin it.

Regards Mark

[Edited on 19/6/11 by mark chandler]


peterwub - 19/6/11 at 09:52 PM

Thanks both for the advice. I'll definitely go for the safe option and monitor the exhaust for all 4 cylinders.

Regards,


Pete


ss1turbo - 11/9/11 at 08:37 PM

I have a Techedge wideband and the instructions state something like 1m from the exhaust valve (or turbo, whichever is the greatest). I was going to have a pair of stubs; one for the wideband and one for the narrowband after tuning. Either way, the sensor needs to be once all 4 pipes have joined up otherwise you're running on assumption which is bad.