Installing Wideband O2 sensor
 

Anybody done this? I have an LC-1 on the way to go with my Street Tuner, and was trying to decide where to put it. I think I have an empty bung on the top of my DP right after the turbo, but wasn't sure that was a good place. Max reccomended temp is 1300 degrees...

Should I go further down into the mid pipe before the cat?

Most people put them in the Uppipe near the turbo end. At least that's where the old Vishnu uppipe's O2 sensor bung was.

i did 3,

all right in that bung where most tuners reccommend it.

they all work fine to this day.

So that's 100% except for all those people w/ 1st gen Vishnu uppipes that put them in the O2 bung that was provided for specifically that purpose, right?

I don't know about 100% of anybody, but I'm pretty sure the up-pipe bung is for the stock EGT, and if it has two, for an aftermarket EGT gauge. I agree that it may well be to hot, especially while tunning in the uppipe. With a 1300 degree max, that is cutting it awful close.

The extra foot of pipe, and the mass of the turbo probably drop the temps by 100 degrees or so I would think.

I would agree that it's much cooler after the turbo.

However, the original non-flex Vishnu up-pipe had a big-ol secondary bung in it that was certainly for something larger than an EGT. I asked the guys at Vishnu what they used it for and Shiv told me it was for a wideband O2 sensor. It was about 3" from the top of the pipe.

You can kinda see it in this picture, it's got a copper crush washer on it:

http://www.seccs.org/gallery/Car%20P...0Installed.jpg

Or look at this tiny, old picture. You can see the O2 bung on the outside of the bend in the top of the pipe.:

http://www.wrxtuners.com/parts/images/vishnu-uppipe.jpg

I'd prove it in person, except I've since replaced my solid up-pipe with a flex-pipe that doesn't have the bung.

Thanks for the pic Scott. I think I'm going to go with after the Turbo to be safe, and because there appears to be a bung there... :)

hey dean...when i had my WB installed with my txs tuner kit they installed it about 6 inches after the turbo in the down pipe. supposedly this is the best place to install the WB. so i figure that your bung is in the right place.

ryan

vishnu discontinued that pipe because it was a poor design. the o2 bung being one of the design flaws.

I need a wideband. How much did that run you? And do you mind hooking me up with a link for the LC-1?

Oh, and did you hear me rev when I drove by your house at around 9pm last night? I saw a light on... muahaha. sorry. :-P

Best deal on a new one I could find was $199 shipped from one of the Innovate dealers on eBay. So all you are doing is saving the $9 bucks or so Innovate charges for shipping...

Don't recall the reving, but please don't try harder next time. :)

That catagorically doesn't make sense. How can you say 100% of people put their sensors after the turbo and in the same sentence say that the people that put them before the turbo fucked 'em up? Is percent now calculated out of 110 instead of 100?

I'm not saying the O2 should be before the turbo, in fact it seems like the top of the DP is a much better place. But you'd make a much better argument if you said "People used to put them in the uppipe before they realize it burnt the sensor. Now everyone puts 'em in the downpipe." instead of "Every last person puts it in the downpipe, and if you think that isn't the abosolutely best place for it you're a fucking idiot." :P

well the IQ above 20 is teh harder part :lol: might make a good 80% have installed after the turbo.

my thinking is why not even further back? say closer to the stock O2? I've seen a lot of tuning where they put the WB in just the tail pipe to tune, for ease I'm guessing, but they still seem to work as long as you have exhaust flow:?:

Check his post before the "IQ above 20" edit. ;) I'd be willing to agree to his modified statement. :lol:

And Mike's right... unless there's a leak in the exhaust, it shouldn't matter significantly where the wideband sensor is installed.

Semantical is not a word.

/pedantic bastard mode off

I was adding to the thread with my understanding of how a shop uses a WB in the tailpipe.

Of course this would not be where I would install one myself but I might consider the stock O2 location because the midpipe is easier to get to if you need to replace and because turbo cars run hot there should still be enough heat at that point to obtain info

The tail-pipe style widebands used by tuners (at least, the ones I've known personally, Shiv at vishnu and Nate at S-Squared) are heated, just like OEM narrowband units. They are also calibrated for use in that spot- they'd read improperly if used in the downpipe. We could probably debate just how precise the readings from either method is, but since they read consistently, and so few professional tuners have issues with overly rich or lean tunes, it's probably safe to use that method.

I want to say APS gives an extra bung in the up-pipe also...........

secondary egt.. we already discussed this.

watch the video : LM-101: LM-1 Installation and Setup

http://www.innovatemotorsports.com/resources/lm101.php

Tail pipe wide band calibration is a touch and go thing at best. To do it reliably, you have to do it for each and every car, and all of the cats have to be at full functional temperature, and then in a range that the stock O2 before the cats is accurate, you test and compare, probably at a couple different load/flow rates.

I doubt there is a single accurate calibration number even for two "identical" cats for how they affect O2 readings. And before the CATs is what you care about the ratio because the cats job is to burn up left over hydrocarbonc which is the A/F sensor is reading.

nice, after watching 4 of those videos, it says everything i JUST said.

and BTW MOST of the bungs welded after the turbo INCLUDE that stupid copper heat sink washer. hence the reason they put it there.

did you get a chance to watch the video, Dean?

ummm, not really. yes the vedio's do say not to put the bung to close to the turbo (with in 6 inches). I think what Dean really cares about are the temps? at 1300 degrees before readings get messed up and a turbo'd car you would have to move it more down steam then even the down pipe, but before the cat.

so I personaly would move it to the bottom of the down pipe and not the top, and if I was running catless I would them put it in the midpipe

Back to the basics.

Have you ever installed a wideband in a car?

where did you put it?

was it the right place?


I have done 3, and ALL are still working to this today.

there is my contribution

d

1. No
2. I would put it in a location that would not exceed 1300 degrees (I personaly dont think the bung at the top of the Downpipe would be below 1300 degrees)
3. It might be an ok place to put it, but are the readings correct? at WOT and 1600 degrees the readings can become false. Sure the mechanics still work but at what accuracy?
4. What do you consider working? The parts aren't destroyed yet so that makes it working? How about accuracy, do the readings match readings done when first installed, or has there been a little data lost due to wear on the device?

:cry: I was trying to help....... I hope!

Phil, Scott, Mike, Ryan I appreciate the constructive portions of your input, I really do.

Thanks.

Dean, the threads have been split. This thread can hopefully continue in a more rational manner.

i have never seen anyone install a wideband "bare" without the washer. everytime i have seen one go in that i didnt install they used a copper washer. which the video is calling a heatsink. very loosely i might add. if you use the bung provided just be sure to use a copper washer and you should be just fine.

also be sure to avoid touching the sensor and all other noobs mistakes like using lube on the threads. do all that. you be jjusssssst fine.

I'm sure you are correct and that with a heat sink (copper washer) everything will be fine.

Dean, if you are a little consernd about temps, maybe install a EGT in there first to get temp readings

I have an aftermarket EGT in the header of cylinder 3, and I get readings over 1400 on occasion. Not sure it is worth moving, and I think I have the bung after the turbo which should be fairly safe. If the EGT starts to get near 15-1600, I may get worried. I'll have to take a look further down the exhaust to see if I have a bung already if needed. The LC-1 kit comes with an extra bung, so I can get that welded in if needed.

yeah i believe post turbo temps should be alot cooler than 1200 degress. my guess would be closer to 1000.

also if the egt is getting close to 1500-1600 u need to be worried about other things than that sensor. like melting down your pistons.

That is why it is in the header on Cylinder 3 and not in the up-pipe. As I understand #3 is the one that is most likely to run lean.

I'm still researching before doing any tuning, and as with everything, there are disputes over max EGTs, but everyone's sensor is in different places.... I think A/F is more important overall, EGT on 3 is a backup watch point, most likely if I get near 100% injector duty which is unlikely on the stock turbo in it's efficiency range.

100% correct. most temps taken @ cyl 3 are 1400-1450 MAX 1500 and you want to worry.

most people see around 1200 in the uppipe which would mean at least 100-200 degrees cooler after the turbo.

that would support the 1000 temp range in the downpipe.

Not sure if this has been mentioned, but I've read you don't want to install a wideband upside down. Baically, no lower than a 3 o'clock or 9 o'clock position. It sounds like this sensor doesn't heat itself so I'd say you'd want it between 6" and 18" from the turbo in the DP.

:huh: How is that? The electrons can't overcome gravity or something? I would go with not allowing it to point down so a random piece of road debris doesn't snap it off...

To be honest, I've wondered the same thing myself. I've seen it mentioned once on Nasioc and once on wrxfanatics. Take it with a grain of salt.

Both sites are, of course, wonderful sources of accurate and correct information :lol:

Yah, yah. :P

I'm thinking BAN SUVS is probably right about avoiding road debris.

and water condinsation

OK, all WB 02s I am aware of for our applications are heated. As I understand, heating ensures the sensor is in it's operating temperature range as well as cleaning the sensor of deposits.

And as I understand, the reson for having it at or near 12:00 o'clock is so crap is less likely to build up on/in it in the exhaust, as well as fall off/out when/if it lands on the sensor. The external portion of the sensor is fairly well insulated from pretty much anything, I think. It should be in my hands tomorrow, so I may know more then.

thats Exactly why.

Nah, just joking around. They are both fine resources. There is a lot of crap (like most of the internet) that you have to wade through. And honestly, I don't know if the info you posted is wrong, or right, I just don't know. I'm willing to take everyone elses answers here, though. Debris and/or water condensation sounds very plausible.

I asked the guy on WRXF and he also says it's to avoid moisture damage.

Soooo +1 :D

External moisture damage, or internal. Sorry, maybe I'm confused because of the mention of road debris.

I can't imagine the external portion of the sensor being anything but sealed. My assumption was that it is the tip of the sensor inside the exhaust that is the issue since exhaust is clearly not clean, especially before the cats, and does include quite a bit of moisture and particles as products of combustion.

Internal moisture is the major potential issue I'd think, but external could be an issue too. You don't want your bung or sensor to sit in water or condensation.

The last thing I want is my bung sitting in water or condensation.....;)

But yes, it's internal condensation. You're already introducing a condensation point, for lack of a better term, with any irregularity in a smooth tube; making sure water doesn't pool when the car is not running and corroding the sensor would seem to me to be the most important goal. It's all going to burn off once the car warms up, but a low spot with external welds means you have pockets for water to sit in and rust/corrode out.

I'm not going to pretend to be an authority on placement, but the DP/midpipe, depending on packaging, is going to be your best bet. The usable life of the O2 sensor is going to be limited by contaminants more than heat in that spot anyways. Even a tailpipe mount (which isn't claimed to be superior, just a much better option than no wideband at all) that doesn't require permanent mods, and is all the way at the end of the exhaust stream, still gets gunked up and wears out after XXX miles.

It comes down to the optimal location, and then the location that gives you more than acceptable results when incorporated with other logging and gauge readings. Unless you're tuning a car to the bleeding edge, using a tailpipe clamp is going to let you keep an eye on AFR's in concert with all of the other information you're gathering to monitor the engine for a good, solid, daily-driven tune.

Water condensation makes perfect sense, since 5-8 gallons of water passes through your exhaust with every tank. Probably not a huge concern, but one of those "why take chances" things.