Extensions or Bosch 13111's?
Thread Starter
Joined: Nov 2003
Posts: 6,216
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From: Wichita KS / Rancho San Diego
Extensions or Bosch 13111's? I'm getting ready install my LT's and wondering if I should use extensions or get new Bosch 02 sensors. The stock ones seem to be working fine; the car has 64,000 miles on it. The 13111's would be double the price of extensions, but then again, they'd be brand new. But if the stockers pretty much last forever, why bother? Opinions?
Im using the Bosch o2's. They work fine for me, and the only time one went out, they are under a 12 month warranty. Some people have problems with them. No matter what if your headers are coated, as the coating on the inside comes off its going to kill one or two.
Tech Resident
Joined: Jan 2006
Posts: 5,117
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From: Philly
i was going to get the bosch 13111's, but after investigating the topic and seeing how many people complain about them being lousy, causing the car to run poorly and all kinds of crap (typically associated with EVERYTHING bosch makes), i decided to get 2 24" extensions and run the stock O2's. when they go out, i'll either get another set of AC Delco or those denso ones people rave about.
In my case, the extensions with the stock O2s didn't work well at all, car kept throwing codes. Got rid of the extensions and stock O2s and put in the Boschs and the car has been fine since...no more codes.
TECH Fanatic
Joined: Nov 2003
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From: MD
Originally Posted by MannyZ28
In my case, the extensions with the stock O2s didn't work well at all, car kept throwing codes. Got rid of the extensions and stock O2s and put in the Boschs and the car has been fine since...no more codes.
Ditto.
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extensions (preferabbly the ones that plug in on both sides )or get the stock vette sensors , seen way way to many issues first hand with the bosh sensors, they dont read as fast and can give driveabilty and tuning issues 
TECH Resident
Joined: Aug 2003
Posts: 970
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From: England UK
For about a year now I've been running LT's, used the stock sensors with extentions. This has been idling fine, the AFR has been good.
About a 2 months ago I change the heads and cam. After a month of tuning and chasing my own ***, I noticed the stock O2's were not switching right, sitting at idle above 17:1 AFR.
So i done a search on the forum, put in Bosch 13111's as they seemed to be highly recommended. After 1 week and 1 day it is occilating around stoch'ish, swinging from 12:1 AFR to 17+ AFR, staying mainly lean. took it for a 20mile drive to warm everything up, still does the same after parking up.
Are these O2's going bad too? Monday night (two days ago) I took the battery off to attached some stereo equipment, I'm leaning towards the idea that the car is relearning the fuel trims, but why would it look the same after 20miles?
I read somewhere that oil can damage these sensors, now there dosn't seem to be any blue smoke when giving it some. Cant see any oil missing from the sump. The catch can has caught about 50ml of oil in 2 months (about 1700miles, quit a few WOT runs in that).
I'm going to log the o2 switching, as I say prehaps its relearning, or perhaps they are going duff already after 100miles.
About a 2 months ago I change the heads and cam. After a month of tuning and chasing my own ***, I noticed the stock O2's were not switching right, sitting at idle above 17:1 AFR.
So i done a search on the forum, put in Bosch 13111's as they seemed to be highly recommended. After 1 week and 1 day it is occilating around stoch'ish, swinging from 12:1 AFR to 17+ AFR, staying mainly lean. took it for a 20mile drive to warm everything up, still does the same after parking up.
Are these O2's going bad too? Monday night (two days ago) I took the battery off to attached some stereo equipment, I'm leaning towards the idea that the car is relearning the fuel trims, but why would it look the same after 20miles?
I read somewhere that oil can damage these sensors, now there dosn't seem to be any blue smoke when giving it some. Cant see any oil missing from the sump. The catch can has caught about 50ml of oil in 2 months (about 1700miles, quit a few WOT runs in that).
I'm going to log the o2 switching, as I say prehaps its relearning, or perhaps they are going duff already after 100miles.
My 13111's work fine. But for the people who dont like Bosch, why not buy another brand of the same application sensor? Like a Denso, Delco, etc. They are just C5 rear o2's.
bosch sensors are good when they work...i seem to hear a lot - A LOT - of instances where people get lazy ones from the factory
odd i know, but when they work they switch WAY faster than stock...they DO seem to be a lot more finicky and sensitive to oil and water though
odd i know, but when they work they switch WAY faster than stock...they DO seem to be a lot more finicky and sensitive to oil and water though
TECH Resident
Joined: Aug 2003
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From: England UK
I've heard a lot of positive things about the 13111's, now I've got them I seem to read bad things.
When I first put them in a 8 days ago they were swinging well, and very tight around 14.6ish, like 14 to 15.4AFR, now they seem to be swinging 12 to 17+ AFR and idling mainly 17+ (cant tell exact number as off WB guage).
I need to do a log and see if they are switching slower than last week. I done a log of first start up when they were installed. I have no cats, and its damp weather here at the moment, so beyond the O2's you could see from one end of the exhaust pipe to the other is the pipes were straight. I read somewhere they a bit of back pressure is needed to read accurately, if thats that case perhaps I need to put the cats back on. How about wraping the exhaust in silver foil will that help retain the heat around the o2's, thats if its a heat issue.
When I first put them in a 8 days ago they were swinging well, and very tight around 14.6ish, like 14 to 15.4AFR, now they seem to be swinging 12 to 17+ AFR and idling mainly 17+ (cant tell exact number as off WB guage).
I need to do a log and see if they are switching slower than last week. I done a log of first start up when they were installed. I have no cats, and its damp weather here at the moment, so beyond the O2's you could see from one end of the exhaust pipe to the other is the pipes were straight. I read somewhere they a bit of back pressure is needed to read accurately, if thats that case perhaps I need to put the cats back on. How about wraping the exhaust in silver foil will that help retain the heat around the o2's, thats if its a heat issue.
I notice a rough idle sometimes too in my car. And it has done that before, so I switched them under warranty, and for a while my car acted brand new, then it just kinda slopes back down again over time. But since all my mounts are poly, I figure thats some of the sake I feel.
Joined: Mar 2007
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From: Saskatchewan, Canada - where arguing "DA" is for the slow and weak...
I have had the Bosch 13111s in my car for about 3 days and ~150 miles now and the car is working fine. I am keeping a close eye on fuel consumption, but already they seems to be an improvement over the factory units with 117K miles on them.