Wideband O2 Sensor
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Driver
Joined: May 2005
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From: Texas
Wideband O2 Sensor
Does it really make a difference if the O2 sensor is installed before or after the cat? PLX M300 instructions indicate the installation should be before the cat but at least 24 inches downstream from the engine block. Stock manifolds on a 430 won't give 24 inches.
Thread Starter
Driver
Joined: May 2005
Posts: 132
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From: Texas
Just talked to the tech at PLX. It can go after the cat. It won't affect the reading. The only issue is the timing of the reading, but the difference is very small. Phew, that made my day. Thanks for the input DX3
Pole Position
Joined: Sep 2002
Posts: 358
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From: FL
hey txgs i've installed a couple of zeitronix widebands on two of my cars and the instructions for those said to install the sensor before the cat for better accuracy. so i'm surprised that they said it was ok to install after the cat.
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Driver
Joined: May 2005
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From: Texas
According to the tech at PLX the accuracy issue has to deal with the timing of the signal. Mounting before the cat will give you a reading sooner than after the cat. But as he said this timing issue is minisucle. You will still receive the same reading just a little later (milliseconds).
Lexus Champion
Joined: Jun 2003
Posts: 2,079
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From: Texas
According to the tech at PLX the accuracy issue has to deal with the timing of the signal. Mounting before the cat will give you a reading sooner than after the cat. But as he said this timing issue is minisucle. You will still receive the same reading just a little later (milliseconds).
JPI
Last edited by GILLEXUS; Nov 11, 2006 at 04:38 AM.
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Pole Position
Joined: Sep 2002
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From: FL
A/F readings don't have to be taken at the tailpipe, some dynos may do that because the car they are dynoing doesn't have a bung for the wb sensor. every dynojet and mustang dyno that i've been on has used my pre-cat wb sensor.
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Thread Starter
Driver
Joined: May 2005
Posts: 132
Likes: 0
From: Texas
How are you able to install a wideband sensor before the cat? There isn't any room to install an additional bung before the cat. Or do you switch the stock narrow band sensor with a wide band sensor?
Joined: May 2001
Posts: 8,702
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From: California
I welded a bung roughly 80 degrees off from the factory sensor on my driver side header.
I'd take a pic but don't think I can do it without putting the car on a lift.
I pulled off my stock O2 and put the wideband there. Usually if your car is NA...the heat will not be as extreme as in a turbo car. I think mine is about 7-8" away from the engine right now.
Also, I thought you get a much more accurate reading if the O2 is before the cats because the air mixture is not yet altered/catalyzed.
Also, I thought you get a much more accurate reading if the O2 is before the cats because the air mixture is not yet altered/catalyzed.
Lexus Champion
Joined: Jun 2003
Posts: 2,079
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From: Texas
JPI
Lexus Champion
Joined: Jun 2003
Posts: 2,079
Likes: 2
From: Texas
I pulled off my stock O2 and put the wideband there. Usually if your car is NA...the heat will not be as extreme as in a turbo car. I think mine is about 7-8" away from the engine right now.
Also, I thought you get a much more accurate reading if the O2 is before the cats because the air mixture is not yet altered/catalyzed.
Also, I thought you get a much more accurate reading if the O2 is before the cats because the air mixture is not yet altered/catalyzed.
His is a GS430 not 300 so it will be a little different from yours.
JPI
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