Front O2 replacement with the LC-1
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Joined: Mar 2007
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From: Connecticut
Front O2 replacement with the LC-1
Why do people weld in bungs for the LC-1?
Since the LC-1 has a narrow band simulated output, can't you just replace the stock front O2 sensor with the LC-1 and feed the analog signal into the stock ECU?
I would image you would need to put a resistor on the heater wires to make it think it's heating up.
Has anyone done this?
Since the LC-1 has a narrow band simulated output, can't you just replace the stock front O2 sensor with the LC-1 and feed the analog signal into the stock ECU?
I would image you would need to put a resistor on the heater wires to make it think it's heating up.
Has anyone done this?
I think 1 of the biggest reason people don't put it in the o2 housings is Innovate recommends not putting it within, I think, 36" of head. The o2 sensor can overheat and give false readings.
Thread Starter
Newbie
Joined: Mar 2007
Posts: 29
Likes: 0
From: Connecticut
So I found this posted from an employee on innovative's forum,
Hi,
I think the myth that the sensor has to be as close to the turbo as possible comes from people who used narrowband sensors. As NB sensors are mainly heated by exhaust gas, you want them close to the turbo. The heater in a narrowband is mainly there to get it to it's minimum operating temp as quickly as possible for emission reasons.
A wideband is temperature regulated. If the temp regulation is working correctly, and not overwhelmed by either too much cold gas or too hot a gas, it does not matter where it is mounted. A good wideband, provided no external gas or other means of changing the exh. gas is introduced, will read the same wether its in the downpipe or in the tailpipe.
Lower exh. gas temps allow more headroom for the sensor heater to regulate the sensor head to a constant temp of 800 degC. Close to the turbo the temps can be high enough that the sensor heater can no longer regulate (it can't cool after all), in which case the LM-1 or LC-1 will display an error, other widebands continue to give numbers (but just wrong ones). The heat stress also shortens the life of the sensor.
The sensor head in a wideband is regulated to 800 degC. If your exh. temps were 720 degC at the sensor location, that is a margin of only 80 degC which the sensor heater has to regulate. That is too small in most cases. Specially because EGT sensors, due to their inherent heat conduction to the pipe, display lower numbers than actual EGT.
BUT, here's another clincher:
Bosch also specs a max temperature at the bung of 570 degC. This is the absolute max rating above which irreversible damage to the sensor will occur. We found that the sensor readings already change (reversibly) at about 500 degC at the bung. The LC-1 and LM-1 can monitor that temperature as well due to a design peculiarity of the LSU4.2 and due to the measurement principle of the LM-1/LC-1. Other widebands can't. If the bung temp is exceeded, an error is produced as well.
A turbo has a relatively large flange area to the down-pipe, which allows a lot of heat conduction into the pipe directly behind the turbo. This means the surface (bung) temperature directly behind the turbo can easily exceed the max bung temp allowed. This is specially true for turbos with internal waste-gates. With those the pipe temperature at the turbo outlet can even exceed the temperature of the turbo housing.
Regards,
Klaus
After reading this, I will be placing my bung a little further downstream from the stocker.
Hi,
I think the myth that the sensor has to be as close to the turbo as possible comes from people who used narrowband sensors. As NB sensors are mainly heated by exhaust gas, you want them close to the turbo. The heater in a narrowband is mainly there to get it to it's minimum operating temp as quickly as possible for emission reasons.
A wideband is temperature regulated. If the temp regulation is working correctly, and not overwhelmed by either too much cold gas or too hot a gas, it does not matter where it is mounted. A good wideband, provided no external gas or other means of changing the exh. gas is introduced, will read the same wether its in the downpipe or in the tailpipe.
Lower exh. gas temps allow more headroom for the sensor heater to regulate the sensor head to a constant temp of 800 degC. Close to the turbo the temps can be high enough that the sensor heater can no longer regulate (it can't cool after all), in which case the LM-1 or LC-1 will display an error, other widebands continue to give numbers (but just wrong ones). The heat stress also shortens the life of the sensor.
The sensor head in a wideband is regulated to 800 degC. If your exh. temps were 720 degC at the sensor location, that is a margin of only 80 degC which the sensor heater has to regulate. That is too small in most cases. Specially because EGT sensors, due to their inherent heat conduction to the pipe, display lower numbers than actual EGT.
BUT, here's another clincher:
Bosch also specs a max temperature at the bung of 570 degC. This is the absolute max rating above which irreversible damage to the sensor will occur. We found that the sensor readings already change (reversibly) at about 500 degC at the bung. The LC-1 and LM-1 can monitor that temperature as well due to a design peculiarity of the LSU4.2 and due to the measurement principle of the LM-1/LC-1. Other widebands can't. If the bung temp is exceeded, an error is produced as well.
A turbo has a relatively large flange area to the down-pipe, which allows a lot of heat conduction into the pipe directly behind the turbo. This means the surface (bung) temperature directly behind the turbo can easily exceed the max bung temp allowed. This is specially true for turbos with internal waste-gates. With those the pipe temperature at the turbo outlet can even exceed the temperature of the turbo housing.
Regards,
Klaus
After reading this, I will be placing my bung a little further downstream from the stocker.
