Oxygen sensor in downpipe. Any advantages?

[V6UnderPressure]

I heard that it would give you a more accurate reading. Anyone else heard otherwise? I know some of the aftermarket computer systems require it in the downpipe. But any advantages with stock computer and T-plus/extender?

Scott

 

[bruce]

Originally posted by Scott4DMny
I heard that it would give you a more accurate reading. Anyone else heard otherwise? I know some of the aftermarket computer systems require it in the downpipe. But any advantages with stock computer and T-plus/extender?

Nope, the aftermarkets using Wide Bands, can be effected by high amounts of Back Pressure, the effect on oem sensor isn't enough to worry about. The oem O2 isn't used in boost conditions, where as the WBs are.

 

[V6UnderPressure]

Thanks bruce! Now another question, even if the difference wasn't significant, would it be ok to do this if I plan on moving to a wideband in the future. Basically what I am saying is, would it hurt to put it there now while I'm at it?

Scott

 

[1KWIK6]

In my experience, the O2 values will be higher at WOT. Example: If I was seeing 770mv in the stock location, it would read ~830mv in the downpipe. Probably related to the lower backpressure and cooler temps in that location.

-HTH-

 

[denn454]

its easier to get to....

 

[turbo2nr]

I have had the same question. My drag Subaru came with a $200 wide band from the factory. Subaru decided to put it before the turbo, same with other turbo cars now made using a wide band and OBDII. I think it is fine before the turbo. I run 30psi with my subaru, and it has Correction at WOT. Seems ok to me.

 

[bruce]

Originally posted by turbo2nr
I have had the same question. My drag Subaru came with a $200 wide band from the factory. Subaru decided to put it before the turbo, same with other turbo cars now made using a wide band and OBDII. I think it is fine before the turbo. I run 30psi with my subaru, and it has Correction at WOT. Seems ok to me.

There's a difference between an oem and a DIY. They have lots of techs, and resources available to tune things, and have to meet the EPA standards.

FWIW, the pre turbo in oems is most likely due to the slower warm up times of a WB, and in those cases, pre turbo would help slightly.

I base my statements on having actually having tried both locations.

 

[bruce]

Originally posted by Scott4DMny
Thanks bruce! Now another question, even if the difference wasn't significant, would it be ok to do this if I plan on moving to a wideband in the future. Basically what I am saying is, would it hurt to put it there now while I'm at it?

GIGO.
Garbage In, Garbage Out.

Engine management is dependent on having good data. Close, like they say is fine for, horseshoes, handgrenades, and nukes. Given hours on end of part throttle useage, and the fact the oem code is designed to allow for things like reporting delays in O2 readings, your best to leave well enough alone, IMO.

If you want to run both a WB, and heated NB, down by where the cat was/is, that's another matter, since you have the WB for redundancy. That's how I have mine, and then I use the stock location for EGT. It all works out well that way, IMO.

Not to mention AFRs, from both the WB, and NB are inferred. You can change the timing, and see the AFR change in either. The AFR indicated, assumes that the timing is close to optimum.

Attention to details, is the name of the game, IMO.

 

[TurboJim]

Dont rule out a decrease in spool time with the O2 relocated. Think of it this way you have what, a 2" pipe to the turbo, now block 1/8 of it with an O2 probe. I took the advice of another guy and my spool time decreased a good amount, and it was good to begin with!

 

[V6UnderPressure]

Jim, (bear with me I'm half asleep). So you are saying that by moving the 02 to the DP that you have decreased spool time? Is this how you have yours set up???

Scott

 

[TurboJim]

Originally posted by Scott4DMny
Jim, (bear with me I'm half asleep). So you are saying that by moving the 02 to the DP that you have decreased spool time? Is this how you have yours set up???

Scott

Check out a couple pics at http://www.turbojim.com/mods.htm

I had my original O2 in the header becaue I know where it used to read, since installing the fast, I was setting up cruise stuff with it. I spoke to RadiusKid who mentioned removing the stock location sensor because it was a restriction, so I tried it and it made a seat of the pants diff in spool, so yes, it works. Plus the fact my whole combo is pretty much balls on as far as everything matching each other, makes for a very responsive setup.

Jim

 

[V6UnderPressure]

Jim, have you done this with a stock setup? I have a Stock ECM, T-Plus w/extender extreme chip.

Scott

 

[TurboJim]

No I havent. For something like this, Bruce is the man. If he says its more trouble than its worth, then it is.

Jim

 

[DCVING 6]

Scott, I thought you had the innovative wide band kit?

 

[bruce]

FWIW, I have 2 extra O2 bungs in my car and truck. I've run different WBs, and NBs back to back, and compared the results, in real time. Even mounted 2 of the same types in different locations to see what effect there were in delay times in O2 responses, both NB, and WB. Not to mention being somewhat involved in the DIY-WB, which in some measure allowed various manufacturers to see how the heater control works, and allowed them to come up with economically priced WBs, a quick google will show the time lines, about the DIY-WB, and all the other econo WBs. Econo meaning less then $1,000 versions.
And this has taken about 7 years, I have at least 25K test miles, and I've spent a fair amount of money in doing all this.

Do as you will, but when you get done, and look at the results, you'll see what I posted was factual, and accurate.

And I learned along time ago, about playing the numbers game, and have elected not to. While some people like seeing numbers, once you post numbers, then too many folks want to rant and rave about why they're numbers don't exactly match your's, so now a days, I just post what the trends that I observed were.

Like I said just a FWIW.

 

[denn454]

i can't really see it helping much. a little bit sure, but so will wiping the dirt off your shoes before you get in.

its not that big, all i can see it really doing is causing turbulence going into the turbo, which might affect something. otherwise you are still moving the same ammount of airthrough the same pipe.

if thats restrictive, then having the 02 on the back of the turbo is also going to be restrictive. granted the downpipe is much bigger than the headder but i really can't see it helping much.

i'd be intrested to see what kind of improvements it makes at the track. i'd be willing to bet very little.

 

[V6UnderPressure]

Originally posted by bruce
FWIW, I have 2 extra O2 bungs in my car and truck. I've run different WBs, and NBs back to back, and compared the results, in real time. Even mounted 2 of the same types in different locations to see what effect there were in delay times in O2 responses, both NB, and WB. Not to mention being somewhat involved in the DIY-WB, which in some measure allowed various manufacturers to see how the heater control works, and allowed them to come up with economically priced WBs, a quick google will show the time lines, about the DIY-WB, and all the other econo WBs. Econo meaning less then $1,000 versions.
And this has taken about 7 years, I have at least 25K test miles, and I've spent a fair amount of money in doing all this.

Do as you will, but when you get done, and look at the results, you'll see what I posted was factual, and accurate.

And I learned along time ago, about playing the numbers game, and have elected not to. While some people like seeing numbers, once you post numbers, then too many folks want to rant and rave about why they're numbers don't exactly match your's, so now a days, I just post what the trends that I observed were.

Like I said just a FWIW.

thanks for the info bruce!

 

[bruce]

Originally posted by denn454
i can't really see it helping much. a little bit sure, but so will wiping the dirt off your shoes before you get in.

its not that big, all i can see it really doing is causing turbulence going into the turbo, which might affect something. otherwise you are still moving the same ammount of airthrough the same pipe.

if thats restrictive, then having the 02 on the back of the turbo is also going to be restrictive. granted the downpipe is much bigger than the headder but i really can't see it helping much.

i'd be intrested to see what kind of improvements it makes at the track. i'd be willing to bet very little.

Once you get past idle speculation, and believing it, you might be amazed what all the world has to offer in the way of information.

How about instead of guessing or speculating then you actually do the work, and get back with me on what you find?.

Your sarcasim, does little to further your point.

BTW, you might note, that most successful race teams look for that *very little*.

 

[turbo2nr]

Too much crap for me to read thru, so will the WB sensor be ok in the stock location, what is the difference in readings, effects. Just the facts. I do not think too much heat is an issue. What would be the major differences, besides the space an o2 takes up in header system. Would readings be about the same, Why not?

 

[bruce]

Originally posted by turbo2nr
Too much crap for me to read thru, so will the WB sensor be ok in the stock location, what is the difference in readings, effects. Just the facts. I do not think too much heat is an issue. What would be the major differences, besides the space an o2 takes up in header system. Would readings be about the same, Why not?

Too much stuff to repost, looks like your out of luck, as far as I'm concerned.

Maybe, try googling for Bosch Wide Band, then temperature compensation, and exhaust back pressure.