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Old 10-17-2006, 08:40 AM   #1
rebos123
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Default Wideband sensor placement

I have searched and researched the info on this and am now more confused than before.
I am thinking about purchasing StreetTuner. I need to install a wideband 02 sensor in order to use the software correctly (and not blow my car up).
I have a buschur 3" tbe with a hi-flow cat installed in the downpipe. There are NO bungs installed on this exhaust other than the one for the stock rear 02 sensor. I have the stock rear 02 sensor installed there. I don't want to install/weld any other bungs on my exhaust.
Can I install a wideband 02 sensor in the stock rear 02 sensor bung? Will I get correct AFR readings? When I had my car protuned, the tuner was using a wideband sensor that was placed in the tailpipe.
Also, if I unscrew the rear stock 02 sensor should I just zip-tie the whole assembly up under the car (protecting the sensor from the elements) or can I just remove the sensor completely since I am using the cobb AP? I have read that even though the AP disables the codes that get thrown if the rear 02 sensor is removed, the ECU still uses inputs from the rear 02 sensor for fuel trims?

summary:
Can I install a wideband 02 sensor in the rear 02 sensor bung?
Will removing my stock rear 02 sensor mess up my idle/fuel trims?

any input is appreciated.
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Old 10-17-2006, 08:45 AM   #2
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if you're going to the expense and trouble of getting a wide band, you should do it right and put a bung before your cat. it's more accurate. my local exhaust shop did it for 15 bucks.
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Old 10-17-2006, 08:59 AM   #3
rebos123
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Well I have read that the wideband 02 sensors dont like the turbulence/heat that installing right after the turbo has. Plus why did the protuner use the tailpipe location if it isn't accurate?
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Old 10-17-2006, 10:12 AM   #4
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Quote:
Originally Posted by rebos123 View Post
Well I have read that the wideband 02 sensors dont like the turbulence/heat that installing right after the turbo has. Plus why did the protuner use the tailpipe location if it isn't accurate?
I'm not sure about that. The sensors do like heat, that is why they have heaters, but I'm no expert. The top of the downpipe after the turbo is a convenient location. You definitly should install it somewhere where water cannot settle (condenstation) on the probe if you leave it in, and install it before any cats.
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Old 10-17-2006, 10:23 AM   #5
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General rule of thumb is you want the o2 12-18 inches away from the turbo. This is because exhaust gas temps can exceed the capability of the sensor.
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Old 10-17-2006, 10:30 AM   #6
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problem is my hi-flow cat is about 12 inches from the turbo.
I guess I can't use Streetuner because I am not going to replace my exhaust system just to install a wideband 02 sensor!!
guess I'll just have to have my car protuned every time I change/add something to it. I wonder how they get accurate readings from their 02 sensors they put in the tailpipe
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Old 10-17-2006, 02:08 PM   #7
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You can put it very close to the mouth of the downpipe. 4" from the flange is what most manufacturers use....take a look at the Cobb downpipe and see where it's wideband O2 bung is.

Tuners can get away with it as they know the "lag" in wideband A/F ratio response and what it means in their tuning. It's perfectly acceptable to use a tailpipe unit for a pro....for you....not so much.
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Old 10-17-2006, 02:14 PM   #8
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Quote:
Originally Posted by Unabomber View Post
You can put it very close to the mouth of the downpipe. 4" from the flange is what most manufacturers use....take a look at the Cobb downpipe and see where it's wideband O2 bung is.

Tuners can get away with it as they know the "lag" in wideband A/F ratio response and what it means in their tuning. It's perfectly acceptable to use a tailpipe unit for a pro....for you....not so much.
I believe turbo XS does this too.
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Old 10-17-2006, 02:17 PM   #9
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Quote:
Originally Posted by Unabomber View Post
You can put it very close to the mouth of the downpipe. 4" from the flange is what most manufacturers use....take a look at the Cobb downpipe and see where it's wideband O2 bung is.

Tuners can get away with it as they know the "lag" in wideband A/F ratio response and what it means in their tuning. It's perfectly acceptable to use a tailpipe unit for a pro....for you....not so much.
Correct, many manufacture the bung at the top of the bell mouth. My turboxs came with the WB about 12 inches from the mouth. Anyways I cannot remember but there are some data plotted on the distance away from the turbo and it made no significant difference. I just cannot remember with all these threads... Anyways as long as it isn't after a cat you should be fine.
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Old 10-17-2006, 02:36 PM   #10
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I guess I will need to find a shop that can weld a bung on stainless steel. At least it appears that the innovate LC-1 comes with a bung. Oh wait - innovate changed their LC-1 communications protocol and now it doesn't work with StreetTuner!!
There sure are a lot of "gotchas" in the quest to tune my own car

Last edited by rebos123; 10-17-2006 at 02:37 PM. Reason: fixed vendor's name
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Old 10-17-2006, 03:47 PM   #11
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Why can't he just replace the 02 sensor on the mid pipe with a bosch wideband 02 sensor?
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Old 10-17-2006, 03:54 PM   #12
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Quote:
Originally Posted by Satans_Rectum View Post
Why can't he just replace the 02 sensor on the mid pipe with a bosch wideband 02 sensor?
He in fact can do just that. For tuning purposes many have done that and installed an O2 faker in place of the stock sensor in order to keep the CEL off.
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Old 10-17-2006, 04:01 PM   #13
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Quote:
Originally Posted by Ron@RalliTEK View Post
He in fact can do just that. For tuning purposes many have done that and installed an O2 faker in place of the stock sensor in order to keep the CEL off.
Also, isn't heat the leading cause of bad readings, 02 sensor failure? That's what my tuner told me.
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Old 10-17-2006, 05:42 PM   #14
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You should get a bung put in somewhere in the same vicinity as your stock 02 sensor.
I had an extra bung welded in for $30, I had mine place on the oposite side of the DP than my OEm 02 sensor and a couple inches higher so both sesnsors do not touch inside the pipe. Works like a charm.

Jay-R
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Old 10-17-2006, 07:49 PM   #15
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i have mine about 8" from the turbo. and don't worry about the protocol change. there wasn't any change. someone just had their LC-1 setup wrong. My LC-1 is less than a month old and works perfect with my streettuner.
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Old 10-17-2006, 08:20 PM   #16
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Quote:
Originally Posted by rebos123 View Post
I don't want to install/weld any other bungs on my exhaust.
I'm sorry but that is what you have to do, unless you want to buy an exhaust that comes with a bung.

A wideband after a cat will NOT be accurte. The car functions better WITH the stock O2 plugged in.
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Old 10-17-2006, 08:25 PM   #17
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mine is about 6-8" away from the flange on the turbo, has been working fine for months now, every wrx/sti should come with this gauge stock!
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Old 10-17-2006, 08:25 PM   #18
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Do it right, weld in a bung.

At full throttle the lag even at the bottom of the downpipe isn't that bad. Like less than the speed of the logger you are using. It's only bad on idle and cruise, but at those points you should be using the factory front O2.
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Old 10-17-2006, 08:53 PM   #19
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What about the sensors that have a narrowband output also. Could you replace the existing o2 and wire that into your ecu?

I am going to be installing the plx m300 soon. Here is a link http://www.plxdevices.com/M-Series_productinfo.htm

Click the more info link under key feature #f:Replace your stock Narrowband sensor
Anyone tried this?
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Old 01-05-2010, 09:37 PM   #20
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Quote:
Originally Posted by Smoby View Post
What about the sensors that have a narrowband output also. Could you replace the existing o2 and wire that into your ecu?

I am going to be installing the plx m300 soon. Here is a link http://www.plxdevices.com/M-Series_productinfo.htm

Click the more info link under key feature #f:Replace your stock Narrowband sensor
Anyone tried this?
bump... me too
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Old 01-05-2010, 11:17 PM   #21
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I have the innovate LC-1 with bung welded 3" behind the mouth of the downpipe. The wideband O2 sensor is throwing the code 8 (it's toast), 9 months later.
I'm replacing the sensor, let's see how long the second one lasts..
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Old 01-06-2010, 10:08 AM   #22
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Did you provide a heatsink for the sensor like it describes in the manual?
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Old 01-06-2010, 11:51 AM   #23
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No.
I've read on the innovate forums about the heatsink and several of the members installing the heatsink, together with a new sensor.
I did not read about them posting a year later yet, that the sensor is still good.
To me, the need for a heatsink suggests that there's too much heat, which means that the bung should be further down. Further down is the converter...
Also, in many treads on NASIOC, the suggestion of putting a bung immediately after the mouth of the downpipe comes up, so I guess it's a good thing that the heat sink came up, so people know they have to use it.
The heat sink is made available by innovate.
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Old 01-06-2010, 12:07 PM   #24
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You can also make your own. They describe how to do it in the manual.
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Old 01-06-2010, 06:46 PM   #25
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any idea why DP manufacturers put the bung so close to the turbo?
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