Misc: Everything Else Air Fuel Gauge 02 Sensor Lambda Sensor
- Thread starter Cyborg
- Start date
First step will be locating the bung for the o2 sensor. The instructions say to mount the sensor at least 18 inches downstream from the exhaust port. The instructions are based on automotive applications and presumably the exhaust temperature under the hood on an car engine will be hotter than a motorcycle pipe out in the breeze. Looking at the location of Ducati and HD O2 sensors it seems they are a lot closer that 18 inches. Closer to help avoid the problems with reversion? Being a wideband sensor it should probably be called a A/F sensor.
Robbed off the net: "To work properly, wideband and A/F sensors require a higher operating temperature: 1292 to 1472 degrees F versus about 600 degrees F for ordinary oxygen sensors."
So perhaps less than 18" is better.
Robbed off the net: "To work properly, wideband and A/F sensors require a higher operating temperature: 1292 to 1472 degrees F versus about 600 degrees F for ordinary oxygen sensors."
So perhaps less than 18" is better.
The output voltage of a wideband sensor varies significantly with temperature so all of them use a feedback current to keep them a constant temperature. As long as you don't get it too close to the exhaust port (i.e. too hot) the only thing the extra heating of the hotter exhaust buys you is requiring less feedback current. In other words, if you place it closer to the head your alternator would benefit by needing to supply a somewhat lower current, but at the possible risk of getting an incorrect reading if the sensor is a little too hot (since the feedback circuit can't supply cooling), and damaging the sensor if it is more than a little too hot.
Everyone seems to use the same Bosch sensor so all instructions "should" be the same (although they're not). For what it's worth, the instructions for mine are to locate the sensor at least 24" from the exhaust port to be sure it does not exceed 900 °F/ 500 °C. At that temperature steel is just starting to have a faint glow, which I've never seen even near the head since the Gold Star's pipe hangs in the breeze instead of being insulated under the hood of a car at the end of a header fed by four cylinders. The (heated) sensor also should be as near as possible to the top of the pipe so water condensation doesn't hit it when the engine starts up and kill the sensor due to thermal shock.
A sensor doesn't like to breathe exhaust when it isn't hot, but neither does it like a blast of cool air filled with H20 vapor on initial startup. So, instructions for mine say to start the vehicle and then immediately fire up the sensor (which takes ~30 sec. to reach operating temperature). Cautions I've read are that the lifetime of these wide-band O2 sensors is degraded by the use of leaded fuel, gasoline additives, excess oil in the exhaust, and oil with high Zn content.
One other note is at some point Innovate started supplying longer bungs to keep the sensor from protruding into the pipe and possibly disrupting flow. I suspect this was just to keep some customers happy who were afraid their cars might suffer a loss of h.p. Anyway, Innovate claimed having the sensor in line with the edge of the pipe rather than protruding into it doesn't affect the reading.
For what it's worth, the sensor in my Gold Star pipe is ~21" from the exhaust port, on the top of the pipe, and on a bung that has the tip barely sticking into the exhaust stream.
Thanks for the feedback. Strange that the instructions for mine say keep it under 800C, quite a bit higher. Its a new kit, so maybe the sensor is different? Mine is a Bosch 17025. I contacted the manufacturer of the A/F gauge and asked about current draw. The reply was max 2.5 amps. I also emailed Bosch and asked about location of the sensor relative to the port. Probably a dumb question from their point of view because I couldn't give them the EGT..... but if I had that, I wouldn't have asked them so we'll see if they have a tech on staff who is sympathetic to a old M/C hooligan. I did mention the relatively close proximity of the exhaust port on Ducati and HD.
I wasn't planning on leaving the sensor in the pipe, just use it to sort out the jetting. I did some reading about sensor failures and they mentioned thermal shock. None of it is mentioned in my instructions, but its produced for car folks who likely all have an ECU that controls the heater etc during startup.
I don't think I'll fret about the sensor protruding into the flow although I suppose a longer bung might help keep the heat down in some applications.
Why sensors fail.
http://www.nzefi.com/bosch-lsu-wide...l-often-aftermarket-performance-applications/
Most of the following video is painfully dry, but an interesting bit at 0:41 of the video where it talks about getting its clean reference air sample in the bridgeable wiring harness. Actually a good idea so if you drive a car in the rust belt and get undercoating applied, the "technician" won't knacker your sensor when he sprays it with goop and cuts off its reference air.
From the Bosch site:
What will damage my oxygen sensor?
An oxygen sensor can fail prematurely if it becomes contaminated with phosphorus from excessive oil consumption, silicone from internal coolant leaks, using silicone sealant in the engine and some over-the-counter fuel additives. Even a small amount of poorly refined gasoline can affect an oxygen sensor. Environmental factors such as road splash, salt, oil and dirt can also cause a sensor to fail – as can thermal shock, mechanical stress, or mishandling.
I wasn't planning on leaving the sensor in the pipe, just use it to sort out the jetting. I did some reading about sensor failures and they mentioned thermal shock. None of it is mentioned in my instructions, but its produced for car folks who likely all have an ECU that controls the heater etc during startup.
I don't think I'll fret about the sensor protruding into the flow although I suppose a longer bung might help keep the heat down in some applications.
Why sensors fail.
http://www.nzefi.com/bosch-lsu-wide...l-often-aftermarket-performance-applications/
Most of the following video is painfully dry, but an interesting bit at 0:41 of the video where it talks about getting its clean reference air sample in the bridgeable wiring harness. Actually a good idea so if you drive a car in the rust belt and get undercoating applied, the "technician" won't knacker your sensor when he sprays it with goop and cuts off its reference air.
From the Bosch site:
What will damage my oxygen sensor?
An oxygen sensor can fail prematurely if it becomes contaminated with phosphorus from excessive oil consumption, silicone from internal coolant leaks, using silicone sealant in the engine and some over-the-counter fuel additives. Even a small amount of poorly refined gasoline can affect an oxygen sensor. Environmental factors such as road splash, salt, oil and dirt can also cause a sensor to fail – as can thermal shock, mechanical stress, or mishandling.
Yours is the newer type that also goes by the code LSU 4.9. Mine is the earlier type LSU 4.2 that apparently is only good for about half the mileage. So, if it takes me 30 miles to get the jetting correct on a bike, the sensor will fail by the time I've jetted my one-thousandth bike. Yours will be good for two thousand, you lucky dog.
Sadly for me, I implemented the latest technology for A/F measurements shortly after it was introduced and it's still 'good enough'. So I'm stuck using technology from early in the Millennium while you get to use the latest in instrumentation. Damn you!
I was hoping that I could further elevate my feeling of superiority by posting a GIF of the "Opening Ceremony" referenced in the poop sheet (post #2). Turns out its not all that gobsmacking. What a letdown.... although the vid was posted in 2012 so maybe they've added some marching band music since then.
Wait, wait! I withdraw my confession of jealousy. Yours is merely a gauge, not a data logger, forcing you to hold the throttle with your right hand, notepad for recording A/F readings and throttle position in your left hand, and pencil between your toes. In stark contrast to your Stone Age mobile note-taking system, I simply hit the 'Record' button on mine and later transfer to my computer up to 44 min. of data of A/F, throttle position, and tachometer readings recorded at 12 Hz to contemplate in the comfort of my home.