Wideband sensor installation position

Hi guys,

Just got my AEM UEGO gauge and sensor. Planning to install it and try to do some optimization using the tactrix soon.
I got a Tomei catless downpipe installed by the previous owner, the AEM manual says that on a turbo engine the wideband should install at least 36 inches after the exhaust port. What are your experiences on it? any catch?

sunfffd said:

...the AEM manual says that on a turbo engine the wideband should install at least 36 inches after the exhaust port. What are your experiences on it? any catch?

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Hmmm...that's interesting. My current downpipe doesn't have a bung welded in from the factory, but my old downpipe
did and it was pretty close to the turbo; downstream 12" or less.

I have mixed feelings about where it should be. On one hand I feel it should be further away because of developed flow, lower temps and better mix. On the other hand I feel it should be as close to the source as possible for better timing of exhaust pulses vs reading. Every inch you move further away, you are some microseconds delayed from actual combustion. So the reading may not be indicative of actual real time AFRs. I believe this is why the stock AFR sensor location is in the collector of the exhaust manifold before the up-pipe. I've tried it in a number of locations, and for me, the best results are at least 6-8 inches down stream of the turbo in the down pipe. It is not so far away that the timing is off significantly and it is far enough away that flow is fairly developed.

Just my edjumakated opinion.

^ Would your choice of position vary at all considering a few variable differences such as:

-IWG turbo w/ bellmouth DP
-IWG turbo w/ partially divorced wastegate DP
-EWG turbo

Naaa. I haven't noticed a difference.

I do notice the further away you go the more stable the readings are. I prefer to be as close to the engine as possible though because a millisecond in a log is a century and when you are calibrating the MAF based on AFR, you may be correcting for a previous voltage for the AFR you are looking at at the moment.

Thanks guys you are all very helpful!

Another question is the White analog output cable from the UEGO, can it be connected to the ECU to replace the stock O2 sensor?
I have already prepared a rs232 outlet for the uego, so the white can be left alone?

sunfffd said:

Thanks guys you are all very helpful!

Another question is the White analog output cable from the UEGO, can it be connected to the ECU to replace the stock O2 sensor?
I have already prepared a rs232 outlet for the uego, so the white can be left alone?

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That would be sweet if it can be done. I'd get a UEGO right away if that is the case. Otherwise, I'd have to have a bung added
to my downpipe.

^ Yikes....Idk if I like the sound of all that.

Though personally, I don't think I'd be too afraid to tap the harness if that was a possible
way of doing this. I'm an electronics type and have a lab with solder station and all at work.

Somehow, I feel like it's more complicated than we all assume.

Fujiwara said:

I can tune a car with a tailpipe clamp and the wideband at the very back of the car -- the least responsive point for the sensor to be -- and at the end of the day -- keep shit as simple as possible.

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That's what all of my past tuners have done while I was on the dyno. The only real reason I want a wideband is so I could log that data and send it to George for example, and he could hook me up with an E-tune. If I wasn't considering E-tunes, I wouldn't be quite so interested in a wideband

Fujiwara said:

That car took an electrical type who has all kinds of certifications roughly two weeks to sort through and I'm not sure it's complete. There are so many problems that figuring out which one is causing what particular issue is just a shot in the dark.

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Ohhhh what a freaking mess.....that sounds like a nightmare. I've had more instances like that than I care to even recall (at work, not on the car). I'm sure that all may have contributed to my slight balding spot. LOL

Batmobile_Engage said:

That's what all of my past tuners have done while I was on the dyno. The only real reason I want a wideband is so I could log that data and send it to George for example, and he could hook me up with an E-tune. If I wasn't considering E-tunes, I wouldn't be quite so interested in a wideband

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same here, another thing is to have one more reference on monitoring the health of the engine
i'm not really planning for an aggressive tune but rather a stable and efficient one, and more on educational purpose for myself

Don't get me wrong, keeping an eye on my AFR readings would be great too... But the requirement for E-tuning was the driving force behind the idea.