ojcool Posted October 15, 2006 Report Share Posted October 15, 2006 So, I find myself unable to resist the urge to use a wideband 02 sensor to tune a couple banshee's . From my reading we are targeting a a/f ratio of about 12.5:1 so I'm tuning for 12:1. Day one: Got an old platic briefcase and drilled some holes in it so I can bungie cord it onto the bike safely... Since it's going to have my laptop in it I want to make sure it will NOT fly off. I have a Innovate LC-1 Wideband 02 sensor with the controller ect.. It also comes with Log Tech software for datalogging the results of the run. First problem encountered it the need for a 12 volt source. I solved this problem by taking the battery off one of my cordless drills to power the LC-1. I just used some aligator clips to get the juice off the battery. Second problem. How to plum in the 02 sensor so I can get a reading. I took a piece of 3" exhust pipe about 8 inches long and welded in the sensor bung. I then just used some metal duct tape to attach it onto the exhaust silencer. Inital results were a little confusing. Mods: LRD adjustables Pro design cool head 20cc domes +4 timing Trail port SRP cages and Boysen 2 stage reeds Impeller upgrade K&N pod filters 320 main 27.5 pilots with 1.5 turns out Elevation is about 186 feet. At idle the bike was blowing 22:1 (yikes) And during the first run the richest A/F I got was 14:1. none of that is any good. Changed to the 340 Main and a 30 pilot. 1 turn out on the airscrew. 19:1 at idle I got a little more consistant results but 13:1 still being the richest I could get through the pull. So, the bike is running better but I am now going to modify the 02 sensor pipe to make sure that I'm not getting an inconsistant reading from air mixing with the exhaust. This is the problem with trying to make readings at the end of the pipe. I'll let you know tomorrow when I make another pull. We will see what comes of it. This could be the next great thing or a complete waste of time. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted October 16, 2006 Report Share Posted October 16, 2006 Just learn how to read the plugs already ....will ya? :biggrin: On every dyno run I've witnessed, on two strokes, the sensor is placed inside the silencer... Perhaps that may be effecting the reading a bit... I can tell you with 99% certainty you don't need a 30 pilot with that setup... 27.5 is plenty fine. I've read of alky banshees using stock carbs (yes...stock carbs, I know...waste) running 30 or 32.5 pilots... Is there a way to heat tape that sensor inside the silencer? Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted October 16, 2006 Report Share Posted October 16, 2006 If you dont place the sensor far enough in the exhaust system then i will pickup on the out side air and show lean. Quote Link to comment Share on other sites More sharing options...
ojcool Posted October 17, 2006 Author Report Share Posted October 17, 2006 No, you can't put it in the silencer. I don't know what kind of sensor the guys you saw were using but the LC-1 has to have the back of the sensor exposed to the outside air to function. It compares what is coming out the exhaust to the oxygen in the outside air. I changed a couple things about the setup now, we will see how it goes. Typically when we use these on cars we weld bungs into the header collectors which, needless to say, is significant further "upstream" from where I'm measuring from. However I have made some changes to the way I'm measuring and I expect much different results this time. I'll keep you posted. Quote Link to comment Share on other sites More sharing options...
1.6i Posted October 17, 2006 Report Share Posted October 17, 2006 No, you can't put it in the silencer. I don't know what kind of sensor the guys you saw were using but the LC-1 has to have the back of the sensor exposed to the outside air to function. It compares what is coming out the exhaust to the oxygen in the outside air. I changed a couple things about the setup now, we will see how it goes. Typically when we use these on cars we weld bungs into the header collectors which, needless to say, is significant further "upstream" from where I'm measuring from. However I have made some changes to the way I'm measuring and I expect much different results this time. I'll keep you posted. thats what i figured, this is the way its done on a dynopak..when tuning cars..the 02 is exposed right at the tip of the exhaust.... Quote Link to comment Share on other sites More sharing options...
djackbanshee Posted October 17, 2006 Report Share Posted October 17, 2006 you are supposed to put your sensor in the front of the pipe near the cylinders, drill holes and get some plugs welded, similar to pyros. Quote Link to comment Share on other sites More sharing options...
ojcool Posted October 17, 2006 Author Report Share Posted October 17, 2006 you are supposed to put your sensor in the front of the pipe near the cylinders, drill holes and get some plugs welded, similar to pyros. Have you seen that done? I don't think thats not going to work because there is unburned fuel traveling back and fourth in the expansion chamber. So it's going to read way rich. I think this is the way it's going to work. The only place that would be better is in the mid pipe but welding bungs in there is out of the question because the sensor would be blocking the pipe and creating so much backpressure you would not be tuning for the true condition. Quote Link to comment Share on other sites More sharing options...
Whitey Posted October 17, 2006 Report Share Posted October 17, 2006 At idle the bike was blowing 22:1 (yikes) And during the first run the richest A/F I got was 14:1. none of that is any good. 22:1 at idle is fine. It should be reading lean as hell becuase there's no strain on the motor so it should be reading mostly air. Also, during partial throttle cruising you should have an oscillation in the O2 readings, if its not your probably too rich. The only time it should have a consistent reading is at WOT. If your getting a constant reading at idle than your most likely too rich. Also 14.1 is not a bad A/F. 14.7:1 is stoich. A 12:1 ratio is something you want when running forced induction, not naturally aspirated. Quote Link to comment Share on other sites More sharing options...
csrmel Posted October 17, 2006 Report Share Posted October 17, 2006 it should only ocsilate if youve got electronic fuel injection which uses an o2 sensor. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted October 17, 2006 Report Share Posted October 17, 2006 22:1 at idle is fine. It should be reading lean as hell becuase there's no strain on the motor so it should be reading mostly air. Also, during partial throttle cruising you should have an oscillation in the O2 readings, if its not your probably too rich. The only time it should have a consistent reading is at WOT. If your getting a constant reading at idle than your most likely too rich. Also 14.1 is not a bad A/F. 14.7:1 is stoich. A 12:1 ratio is something you want when running forced induction, not naturally aspirated. Very Good info...Whitey... I was going off experience his jetting was a bit rich, you sure put it into words with a tech explanation nicely. Whitey...you get that turbo bike up and going yet? Love to see a vid. Quote Link to comment Share on other sites More sharing options...
Whitey Posted October 17, 2006 Report Share Posted October 17, 2006 it should only ocsilate if youve got electronic fuel injection which uses an o2 sensor. Depends if your running an open or closed loop o2. You still should have oscillation even with a carb. Quote Link to comment Share on other sites More sharing options...
ojcool Posted October 17, 2006 Author Report Share Posted October 17, 2006 Well, I'm not sure a banshee engine would be considered "naturally aspirated" since the expansion chambers are supposed to function like a supercharger at rev. On cars we don't see much of a variance in A/F ratio at cruise with a carburator. Only in fuel injected applications where the fuel trims are constantly working. I can't say with accuracy this would be true on a banshee however I would not expect to see it. I would have reservations tuning for anything leaner than 13:1 on a banshee, but I have only just started fooling with them. I would be curious to see some data logs from one being tuned with a wideband, if anyone has some, please post them. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted October 17, 2006 Report Share Posted October 17, 2006 Well, I'm not sure a banshee engine would be considered "naturally aspirated" since the expansion chambers are supposed to function like a supercharger at rev. You lost me there. I'm going to kinda make up a word since I can't recall the exact term for it...but, here goes. I don't think the "sonic reverberation" from two strokes can be considered the same as a superchargers.... A sc's main funtion is forcing more gas and air into the intake/carb/FI by means of a belt or other mechanical driven turbine. Where the exhaust at lower RPMs has sonic waves bouncing back and forth...up until a certain RPM.... The term naturally aspirated to me means any means other than "Forced induction", a la turbo or supercharger....or even Nitrous. This is a very interesting thread indeed, one we ALL can learn from! I could be 100% backwards on my statements above....so, someone clear the air if I'm way off.... I'm not taking anything away from the HQ...but, I'd bet if you posted this over at the 2 stroke section on planetsand.com, you'd get a WEALTH more of knowledge and first hand experience from those boys, from mild to wild.... Big motors, turbos, alky and NOS are common place for a lot of the hard core guys over there. If it can be done, I'm sure they've done it.... Quote Link to comment Share on other sites More sharing options...
Whitey Posted October 17, 2006 Report Share Posted October 17, 2006 Well, I'm not sure a banshee engine would be considered "naturally aspirated" since the expansion chambers are supposed to function like a supercharger at rev. On cars we don't see much of a variance in A/F ratio at cruise with a carburator. Only in fuel injected applications where the fuel trims are constantly working. I can't say with accuracy this would be true on a banshee however I would not expect to see it. I would have reservations tuning for anything leaner than 13:1 on a banshee, but I have only just started fooling with them. I would be curious to see some data logs from one being tuned with a wideband, if anyone has some, please post them. a Banshee motor is naturally aspirated becuase the only intake pressure it recieves is from the atomsphere. If you put a boost gauge on a Banshee its going to read 0 boost, no matter what expansion chamber is on it. Quote Link to comment Share on other sites More sharing options...
ojcool Posted October 18, 2006 Author Report Share Posted October 18, 2006 You lost me there. I'm going to kinda make up a word since I can't recall the exact term for it...but, here goes. I don't think the "sonic reverberation" from two strokes can be considered the same as a superchargers.... A sc's main funtion is forcing more gas and air into the intake/carb/FI by means of a belt or other mechanical driven turbine. Where the exhaust at lower RPMs has sonic waves bouncing back and forth...up until a certain RPM.... The term naturally aspirated to me means any means other than "Forced induction", a la turbo or supercharger....or even Nitrous. This is a very interesting thread indeed, one we ALL can learn from! I could be 100% backwards on my statements above....so, someone clear the air if I'm way off.... I'm not taking anything away from the HQ...but, I'd bet if you posted this over at the 2 stroke section on planetsand.com, you'd get a WEALTH more of knowledge and first hand experience from those boys, from mild to wild.... Big motors, turbos, alky and NOS are common place for a lot of the hard core guys over there. If it can be done, I'm sure they've done it.... I disagree. A two stroke engine is almost exactly like a supercharged engine save three very distict differences. 1 the boost is created by the "sonic reverberation" 2 the boost is only significant at the rpm that the expansion chamber is tuned for. 3 the boost enters from the exhaust port instead of the intake. Any way you slice it at certain RPM's the volume of the cylinder is beyond 100% of the stroke. Therefore it is not what I would call "naturally aspirated" although Whitey's definition does appear to fit. A supercharger does not create boost with a "turbine" it is created via centrifugal force with an "impeller" in the vortec style blower, via positive dispacement with a "roots" style blower and and contrary to popular belief a turbocharger is "thermally" driven, not mechanically. When a turbocharger is pushed beyond its efficency it becomes mecanically driven via the backpressure on the turbine wheel, however this actually costs power and is why turbochargers are rated in CFM and Trim. This is also why you can command any amount of boost you want, however is will not continue to make power. The exhaust temperatures will simply increase to the point of literally melting the turbine and destroying the turbo. This is why they have a wastegate to bypass the turbine after it's efficiency has been reached (if your wise enough to set it there) A turbocharger works the same as a centrifugal blower on the compressor side of the housing. Nitrous oxide works in two simple ways, neither of them involve increasing the amount of air in the combustion chamber beyond 100%. But I digress, what we are really talking about is if 14:1 is a safe A/F ratio for a banshee engine, it is my contention that is would be unwise because the increase of combustion pressures at certain RPM's would dictate that more fuel be added to lower the combustion temperatures, and more importantly prevent detonation. Quote Link to comment Share on other sites More sharing options...
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