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Narrowband O2

 
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Scott Newton



Joined: 29 Dec 2008
Posts: 191
Location: United States, New York, Chittenango

PostPosted: Wed Feb 24, 2010 6:55 pm    Post subject: Narrowband O2 Reply with quote

Obviously wideband is preferred, but came across someone selling everything I'd need for a narrowband setup (sensor, guage, etc.) for a very reasonable price.

Would it provide me with any useful data? Right now my only way of tuning the engine is "does it run" and reading plugs - not a very scientific method. I plan on getting my EGT guages hooked up ASAP, but might hook this up as well.
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Chris Reinhardt



Joined: 04 Dec 2005
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Location: United States, New York, Ossining

PostPosted: Wed Feb 24, 2010 9:15 pm    Post subject: Reply with quote

I don't think you can run an O2 sensor with a 2 stroke, the mix will foul the sensor.

CR
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Steven Cagle



Joined: 21 May 2009
Posts: 149
Location: United States, South Carolina, Simpsonville

PostPosted: Wed Feb 24, 2010 9:48 pm    Post subject: O2 Sensors for two-stroke engines Reply with quote

An O2 sensor will have shortened life with a 2S, but you might be able to collect enough useful data for carb tuning. The accuracy may also be reduced, but it would be an improvement over current methods. You might also be able to correlate O2 data with EGT readings, so that EGT becomes more useful for fine-tuning.

To protect the O2 sensor, consider the angle in which it is installed to prevent liquid accumulation. Also, a protective screen of an appropriate high temp alloy may help slow sensor fouling.

When I worked with 2S engines in an Engineering capacity, we used CO readings to gauge A/F ratio. We also captured O2, HC, NOx and CO2 with a $100,000+ emission analyzer. I still have the Horiba coffee mug from when the company purchased this analyzer.

While thinking about your question, I found the following info on the more expensive wide band sensors:
http://performancetrends.com/wide_band_uego.htm

If you decide to buy the O2 sensor, please let us know how it works out.
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Chris Eckles



Joined: 04 Nov 2006
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Location: United States, Georgia, Atlanta

PostPosted: Thu Feb 25, 2010 6:28 am    Post subject: Reply with quote

I use a wideband to tune my engine. A narrow band sensor would not give you any useful data AT ALL. Another factor is that you need to correlate sensor readings with carb setting. If your carb has a number of different jetting ranges (and it does. . .) - by which I mean "at 3/4 throttle the such-and-such jet is the primary jet" - then you need fair precision in this. And I don't know about you, but I find it nearly impossible to look at my dash on an autocross course.

My sensor lives for two reasons. First, I have a switch that lets me turn on the integral heater, and heat 60 seconds before starting the engine. Second, It spends nearly all of its time on the shelf of my shop. Tune and forget. I do install it once in a while to check.

Chris Eckles
Atlanta
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Chris Reinhardt



Joined: 04 Dec 2005
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Location: United States, New York, Ossining

PostPosted: Thu Feb 25, 2010 7:36 am    Post subject: Reply with quote

With my karts, I have always tuned with an EGT and a weather station/RAD Gauge, and our 125's had to be spot on, or you were in the back. Maybe a better use of money would be to be a data aq system so you can plot the data rather than try and glance at the gauge?
You can find a nice used data aq system like a Mychron 3 gold for less than $500, it will do track mapping 2 temps, tach......


CR
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Jim Murphy



Joined: 16 Mar 2007
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Location: United States, Georgia, Dunwoody

PostPosted: Thu Feb 25, 2010 7:39 am    Post subject: Reply with quote

Scott,
Fix your EGT gauges with fast reading sensor tips and buy a Relative Air Density Meter and learn the effect each change in RAD affects the EGT's.
Remember keep the EGT's under 1,250 degrees. You will notice that coolant temperatures also affect the EGT as well. Then once you are comfortable with this then install a data acquisition system for around $400 or less like the Digatron with 4 displays - 2 EGT's, RPM and Speed. Maybe consider one with 5 displays and add coolant temperature as well. They come with computer software and PC connection cable to download each track session which allows you to closely analyze what is happening on your laptop. The more you learn the better it will be for you.

Jim
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Jeff Colegrove



Joined: 16 Jan 2008
Posts: 841
Location: United States, New York,

PostPosted: Thu Feb 25, 2010 10:04 am    Post subject: Reply with quote

Jim Murphy wrote:
Scott,
Fix your EGT gauges with fast reading sensor tips and buy a Relative Air Density Meter and learn the effect each change in RAD affects the EGT's.
Remember keep the EGT's under 1,250 degrees. You will notice that coolant temperatures also affect the EGT as well. Then once you are comfortable with this then install a data acquisition system for around $400 or less like the Digatron with 4 displays - 2 EGT's, RPM and Speed. Maybe consider one with 5 displays and add coolant temperature as well. They come with computer software and PC connection cable to download each track session which allows you to closely analyze what is happening on your laptop. The more you learn the better it will be for you.

Jim


Mychron 3 might not be a bad option either. Accelerometer for mapping along with the capability to log brake / throttle / steering position. I think I'm going to wind up with one for next year. It will be worth almost as much as my car lol.
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Scott Newton



Joined: 29 Dec 2008
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Location: United States, New York, Chittenango

PostPosted: Thu Feb 25, 2010 10:42 am    Post subject: Reply with quote

Got a second offer on a WB02 w/ guage for a real good price (< 30% retail). I'm gonna pick it up for help with tuning. Obviously won't be much help during autocross runs, but I plan on doing a few visits to the drag strip for tuning purposes, and it should be useful there. I figure if I can get a good baseline at the drag strip using the WB02 + EGT's + Air Density, I can then extrapolate that data using the air density gauge to run a similar tune at events.

Q for Chris though - where did you mount the WB02 sensor? There's not much room in my tailpipe (Kawi dual pipes are smaller than Rotax single pipe), and I assume it's useless in the expansion chamber. Do you have any issues with the WB02 sensor actually blocking the exhaust flow?
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Chris Eckles



Joined: 04 Nov 2006
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PostPosted: Thu Feb 25, 2010 11:06 am    Post subject: Reply with quote

About 10 inches back in the expansion chamber. On the side. There is much argument and debate on this. . . The 2 stroke motorcycle racers change locations year to year. Usually one of the big (rich) teams shows up with the sensor in a different location, then at the next race everyone's got it there. . . Laughing

There are discussions about outside air being sucked in, but idunno bout that. No one does it in stinger, or just out of the engine, all in the expansion pipe.

The really tough part is figuring out your target range. I measure this in millivolts (and my number cost me a lot, so no I won't tell Twisted Evil ). You cannot actually calculate A/F ratio with these things, strangely, and Lambda is a ghost, calculated. So rather than chasing "12" or whatever, you chase 123 mv (a wrong, made up number, far too low). You need data acq for this.

And on one day, it will be perfect. Great power & throttle response. Plugs perfect. Pistons read great. Record the temp, humidity, and barometric pressure (You can get this on line for most cities). Then use a spreadsheet to calculate the jets needed for the next event (night before). SS's available for free on the net, though mine is a bit more sophisticated.

To do it right, you actually develop this number with your car on a dynomometer. Can be done with math, though.

Oh, and if you're using pump gas. . . an exercise in futility.

Chris Eckles
Atlanta
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Scott Newton



Joined: 29 Dec 2008
Posts: 191
Location: United States, New York, Chittenango

PostPosted: Thu Feb 25, 2010 11:58 am    Post subject: Reply with quote

Chris Eckles wrote:
About 10 inches back in the expansion chamber. On the side.


Any pictures of where it is on your car? I imagine it's more a % of the way back in the chamber that matters. Something like 75% to the rear sound right?

Quote:
You cannot actually calculate A/F ratio with these things, strangely, and Lambda is a ghost, calculated. So rather than chasing "12" or whatever, you chase 123 mv (a wrong, made up number, far too low). You need data acq for this.


Isn't this what the guage does - translates the mv signal into an A/F ratio and displays it? From the sounds of it, the A/F ratio in the sensor may not be the actual A/F ratio (especially if it's in the combustion chamber), but it should be off by a linear amount, right? What would be the difference between reading a real-time result off a guage and a real-time result from data acquisition (besides one having the obvious logging ability)?

Quote:
And on one day, it will be perfect. Great power & throttle response. Plugs perfect. Pistons read great. Record the temp, humidity, and barometric pressure (You can get this on line for most cities). Then use a spreadsheet to calculate the jets needed for the next event (night before). SS's available for free on the net, though mine is a bit more sophisticated.


That's the plan. I know with a dyno and a data logger I could achieve this much easier and more accurately, but for now my budget is leading me down the WB02 guage + EGT's + reading plugs & pistons path.
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Richard Schmidt



Joined: 27 Dec 2007
Posts: 340
Location: United States, Minnesota, Plymouth

PostPosted: Thu Feb 25, 2010 12:13 pm    Post subject: O2 Sensor and Kawasaki Reply with quote

Scott,

Highly recommend that you get some type of data recorder. I use a Digatron and it works for me.

I would not run the Kawasaki EGT's more that 1200degs. The edges of the pistons will start to melt at anything over that. Experience has shown me that about 10 seconds of EGT over 1250 will melt down the OEM type piston.

Richard
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Jim Murphy



Joined: 16 Mar 2007
Posts: 1487
Location: United States, Georgia, Dunwoody

PostPosted: Thu Feb 25, 2010 12:25 pm    Post subject: Re: O2 Sensor and Kawasaki Reply with quote

Richard Schmidt wrote:
Scott,

Highly recommend that you get some type of data recorder. I use a Digatron and it works for me.

I would not run the Kawasaki EGT's more that 1200degs. The edges of the pistons will start to melt at anything over that. Experience has shown me that about 10 seconds of EGT over 1250 will melt down the OEM type piston.

Richard
KBS #6


Scott,
I forgot to notice that you have a Kawi - it has coated aluminum cylinder walls which are VERY sensitive to coolant temperatures higher than 150 degrees so whatever it takes to bring the temp's down to 120 or lower will make the cylinders last longer (won't lose compression as fast when they become egg shaped).
Forget about any O2 sensor as you won't get your money's worth, especially in autox. Once you have your data acquisition go test in a remote parking lot at least 100 yards or longer to determine what jetting you need and then to tune your clutches to your pipe (this assumes that you have the optimal final drive ratio for solo).

Jim
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Chris Reinhardt



Joined: 04 Dec 2005
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Location: United States, New York, Ossining

PostPosted: Thu Feb 25, 2010 12:32 pm    Post subject: Reply with quote

Honestly, just an EGT or a O2 would be useless without data aq and a good weather station/RAD gauge. What you need to do is the lean on the mother till you start getting some deto, record the weather station data/relative air density. Once you sneak up on that sweet jet and have the RAD that goes with it, then you go back to the weather station for a current RAD and adjust your jetting up or down by the percentage of change from the baseline.

The only thing an EGT or O2 is going to is verify that RAD and Jet are correct by giving you a read out of xxxx which is equal to your sweet jet and baseline RAD. You're not going to know what xxxx is until you're past it...

There isn't a tool, gauge or computer in the world that's going to tell you what jet to use, it's trial and error....

CR
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Chris Eckles



Joined: 04 Nov 2006
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Location: United States, Georgia, Atlanta

PostPosted: Thu Feb 25, 2010 1:38 pm    Post subject: Reply with quote

Quote:
Isn't this what the guage does - translates the mv signal into an A/F ratio and displays it?


Nah. An oxygen sensor actually is an "oxygen ratio" sensor. You're not measuring fuel, and not measuring air. Same quantity of fuel and air can change this ratio based on type of fuel and engine conditions.

Chris Eckles
Atlanta
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Ed Capullo



Joined: 16 Mar 2007
Posts: 532
Location: United States, Connecticut, Norwich

PostPosted: Thu Feb 25, 2010 3:04 pm    Post subject: Reply with quote

Chris Eckles wrote:
About 10 inches back in the expansion chamber. On the side. There is much argument and debate on this. . . The 2 stroke motorcycle racers change locations year to year. Usually one of the big (rich) teams shows up with the sensor in a different location, then at the next race everyone's got it there. . . Laughing
Chris Eckles
Atlanta

Many of you are too young to know or remember this but Bill Jenkins was the "Q" of Chevy Superstock racers back in the late 60s early 70s. At one of the night races he showed up with small holes drilled into each header pipe near the exhaust port. Everyone was amazed at this new speed secret (actually he was checking the exhaust flame color and jetting by that) but the next day many Chevys had holes without anyone knowing why. It became so absurd that when his SS/D Nova ran ( I forgot that driver) it had a black door frame pillar and sure enough many of my competitors painted their pilllars black. I guess you can't do this with a 2 stroke but my B Dragster front engine rail back in 72 had short stacks and I could also tell the lean cylinders by looking at the flames. Now I just use RAD and read the plugs ( correctly) and note that from aviation we learn that EGT will read to "peak" and if gone beyond peak will start dropping again.
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