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Post by Thebatman on Feb 18, 2011 20:18:25 GMT -5
It doesn't really matter though, any color works. I used to have green strobes in all of my marker lights on the stang and I people would still pull over if I turned them on at night. lol I rode around one night with a cheap little yellow flashing light with a magnetic base. I rode by a drug spot one night and I got my friend to plug the light in just as I mashed the gas coming at the area. People were haulin' ace. Read more: 49ccscoot.proboards.com/index.cgi?board=builds&action=display&thread=516&page=31#ixzz1EMaSH7Ho :rofl: :rofl: that's classic.... I bet they were... :burnout: |
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Post by bigkahuna427 on Feb 21, 2011 14:17:15 GMT -5
I guess I am about half way through reading this thread. I have owned a good number of two stroke dirt bikes in my younger days but never messed with them performance wise. Some of the stuff you guys are doing is really cool and there is a lot of really good info here. I am just curious if you have a way of determing the correct air fuel ratio when you are tuning these. When I was an auto tech we used exhaust gas analyzers and if you knew how to read the figures a four gas analizer could really help nail down issues. Of course a four gas analyzer is expensive but what about an O2 sensor mounted in the exhaust stream to judge rich or lean conditions? Not sure how two stroke oil would affect the reading but you are really comparing the difference of O2 level between atmospheric and exhaust stream. There is a direct relation to O2 and and rich lean conditions. Just thinking out loud from an old driveability guy.
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Post by 90GTVert on Feb 21, 2011 14:28:22 GMT -5
I'm low tech. lol I do old fashioned road tuning and SOTP tuning. I take it uip and down the road over a set distance and record max RPM and max speed in both direction and average them out. Check the plug color. Swap jets, new plug, same thing. Repeat until I'm satisfied that I've chosen the right jet. If it's really windy, I'll go with the richer of the best results and repeat on a calm day. I get the needle positions and the rest sorted out by feel and watching for smoke and such. I know nothing about the analyzers. I believe a wideband would work, they're just expensive. My Innovate was about $200 for just the sensor, controller, and bung. Then you'd need a gauge (or a logging device) that isn't cheap either. Just more than I want into the scoots. 2T oil is hard on sensors, but Koso makes an adapter for 2Ts. www.bikebandit.com/koso-air-fuel-ratio-meter-2-stroke-adapter |
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Post by bigkahuna427 on Feb 21, 2011 15:36:54 GMT -5
I'm low tech. lol I do old fashioned road tuning and SOTP tuning. I take it uip and down the road over a set distance and record max RPM and max speed in both direction and average them out. Check the plug color. Swap jets, new plug, same thing. Repeat until I'm satisfied that I've chosen the right jet. If it's really windy, I'll go with the richer of the best results and repeat on a calm day. I get the needle positions and the rest sorted out by feel and watching for smoke and such. I know nothing about the analyzers. I believe a wideband would work, they're just expensive. My Innovate was about $200 for just the sensor, controller, and bung. Then you'd need a gauge (or a logging device) that isn't cheap either. Just more than I want into the scoots. 2T oil is hard on sensors, but Koso makes an adapter for 2Ts. www.bikebandit.com/koso-air-fuel-ratio-meter-2-stroke-adapterWell doing what I am suggesting is low tech compared to a four gas machine. I think the thing in the link measures exhaust temp and displays an aproximate A/F ratio. A one wire oxygen sensor should be pretty reasonable these days although I have not bought one in some time. You would need to be able to weld or braze a nut or threaded boss into the exhaust pipe. I would suggest maybe 8" from the exhaust port. Once heated the O2 sensor is capable of generating a voltage from .1V to about .9V. There are two ends of the sensor one is exposed to the outside the other in the exhaust. The bigger the difference between outside and exhaust the larger the voltage is. The more O2 in the exhaust the lower the voltage will be and the less O2 the higher the voltage. At .9V the engine is rich and at .1V the engine is lean. So at WOT or accelerating under load you should be at .9V and at cruise .5V or so. The O2 sensor needs to be hot to work and at idle it may not be hot enough to accurately give a reading. So, obviously the perfect air fuel at idle is obtained bu the usual methods. It could take out a lot of the guess work when tuning. Once installed you would just need to duct tape a DVOM on so you can read while driving. Of course this would be a set up for testing after you could plug the hole in the exhaust with a plug. Just some thoughts....  |
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Post by 90GTVert on Feb 21, 2011 16:29:23 GMT -5
I thought a standard O2 ranged from 0.2V to 0.8V and stoich was about 0.45V. I had a narrow band O2 gauge on my car for a bit. I found it to be worthless for the most part. I could tell when it was ultra rich or ultra lean and I could get some idea of the state of tune at WOT, that's about it. The constant cycling of the narrow band sensors made them really tough to read at anything less than WOT. I can only imagine a regular voltmeter would be even harder to try to read while cross counting than the light show. Maybe the single wire O2s act different?
A good wideband is heated, calibrated, and much more precise. To me, and I'm no expert, it just seems like if it's worth doing, it's worth doing right. I feel like I could do just as well tuning my way as with a narrow band. I do not feel like I could do as well as a wideband for getting it all right, especially not in a reasonable time frame. I may be all wrong on this, never used one on a scoot. This is just based on my experience with cars. I'm no pro at that either, I just tinker with a little Mustang mostly.
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Post by bigkahuna427 on Feb 21, 2011 16:48:35 GMT -5
I thought a standard O2 ranged from 0.2V to 0.8V and stoich was about 0.45V. I had a narrow band O2 gauge on my car for a bit. I found it to be worthless for the most part. I could tell when it was ultra rich or ultra lean and I could get some idea of the state of tune at WOT, that's about it. The constant cycling of the narrow band sensors made them really tough to read at anything less than WOT. I can only imagine a regular voltmeter would be even harder to try to read while cross counting than the light show. Maybe the single wire O2s act different? A good wideband is heated, calibrated, and much more precise. To me, and I'm no expert, it just seems like if it's worth doing, it's worth doing right. I feel like I could do just as well tuning my way as with a narrow band. I do not feel like I could do as well as a wideband for getting it all right, especially not in a reasonable time frame. I may be all wrong on this, never used one on a scoot. This is just based on my experience with cars. I'm no pro at that either, I just tinker with a little Mustang mostly. Your mustang is another whole deal. That car has a computer controlled injection system. which lookks to the O2 to keep things in check and perhaps make adjustments. A one wire just has no heating element to heat it up. Here you are dependent upon the exhaust stream to heat the sensor. A dvom will take snap shots of say a voltage and display them one at a time. It's really trying to hit a moving target. If it were taking real time readings the numbers might be moving so fast you could not read them in a situaion where the voltage were not stable. So an O2 may be better read on something that can be displayed as a graph where you can see the tendency is to be here or there. I am suggesting you use this to decide if you are rich or lean at say cruise and under load. WOT .9V and I have seen at times over 1V. Cruise should be around .5V but remember the volt meter is just taking snap shots so you have to inerpret those snap shots. So if you are seiing .6 .4 .6 .4 you are in the ball park. This is far more accurate than pulling plugs and burning pistons. My guess is that if you are burning pistons you are at an extreme. A meter more sophisticated could graph it for you but lets not go there cause we are talking serious bucks. |
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Post by 90GTVert on Feb 21, 2011 19:47:39 GMT -5
I've only burnt one piston so far. That was an aluminum kit that is more prone to holing pistons. I've since learned that the stock carburetor can be hard or impossible some say to make work properly at all throttle positions with such a kit. Not saying it wasn't my fault, but I do think that was a difficult circumstance. Not to mention it happened with a tailwind, going downhill, so the engine was revving but the throttle was nearly closed so there wasn't a whole lot of fuel being delivered in that circumstance. Prior to that, I had no trouble with the tune. Again, not saying I'm good or don't make mistakes, but I would be incredibly surprised if tuning with an O2 saved me from that particular circumstance.
What I do is basically like a homemade dyno. I don't mean to church it up since I'm just riding down the road and recording numbers, but that's about as close as most of us can afford to a dyno lol. I'm tuning for the max power that shows me a good plug and piston read. If I test every jet size till I see max power, I'm just not sure what I would gain by using an O2. I could see it being useful if the O2 would respond well at part throttle. I just have my doubts that it will. If it did, I could tune leaner most likely. I tend to set them up on the rich and safe side now. Of course if you think about it that way, wouldn't that make me more likely to burn a piston under strange conditions if I set them up a little leaner since I'd know the figures?
Another thing that has made me biased, was watching my old narrow band show just shy of full rich. In reality it was so rich that I had gas in my fuel. (The stock EEC-IV just couldn't handle the big injectors no matter how I adjusted anything short of chipping it.) I was wondering if I needed to actually dip the sensor in gas to see full rich. lol If I see my wideband on 16:1, I'm scared. If the narrow band went to lean I just figured who the hell knows what that thing is doing?
All that debate aside, you are getting my curiosity up. Maybe when I get some money together at some point I'll try it? Maybe not? I never even know what I'm gonna get myself into next. lol The single wire narrow O2 would sure fi the budget easier... but how cool would it be to hook up something like the LM-1 to a laptop with their datalogging software on test runs? I've already got the laptop and the software because I use it for the car. I've got the sensor too, but all my wiring is hidden and there's no chance that I'm undoing all of that to go back and forth with scoots. lol It would be worth the money not to do that.
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Post by 190mech on Feb 21, 2011 20:05:44 GMT -5
2strokes,especially piped ones are difficult to get any real data in the exhaust as flow is going in both directions,some of the mixture charge is pulled into the pipe and reverted back in...
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Post by 90GTVert on Feb 21, 2011 20:18:14 GMT -5
Yeah, I've never really read anyone speaking about how that works with o2s. Snowmobilers use widebands (EGTs too), so I assume it has potential.
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Post by 190mech on Feb 21, 2011 21:08:00 GMT -5
I thought it was a good idea too,the 2 stroke road race bunch tend to still tune by feel and plug checks from what I've read..
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Post by stepthrutuner on Feb 21, 2011 22:29:36 GMT -5
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Post by bigkahuna427 on Feb 22, 2011 7:37:25 GMT -5
Another thing that has made me biased, was watching my old narrow band show just shy of full rich. In reality it was so rich that I had gas in my fuel. (The stock EEC-IV just couldn't handle the big injectors no matter how I adjusted anything short of chipping it.) I was wondering if I needed to actually dip the sensor in gas to see full rich. lol If I see my wideband on 16:1, I'm scared. If the narrow band went to lean I just figured who the hell knows what that thing is doing? All that debate aside, you are getting my curiosity up. Maybe when I get some money together at some point I'll try it? Maybe not? I never even know what I'm gonna get myself into next. lol The single wire narrow O2 would sure fi the budget easier... but how cool would it be to hook up something like the LM-1 to a laptop with their datalogging software on test runs? I've already got the laptop and the software because I use it for the car. I've got the sensor too, but all my wiring is hidden and there's no chance that I'm undoing all of that to go back and forth with scoots. lol It would be worth the money not to do that. I have been out of the business for over ten years so to be honest I am not sure what a "wideband" O2 is. Sounds like a term that some marketing folks in the performance world came up with to sell O2 sensors. Look an O2 sensor measures oxygen content in the exhaust and with that information you can get a decent idea of where your mixture is at,,,, simple. It needs to be hot to work and might not give real good readings at idle with a small displacement single cylender engine. I myself would just use this for tuning once you have jetted the carb you are done. If you had a latop recording readings that might be cool to graph things out but might be tough to hang onto while hitting the gas and driving... A DVOM might make things look confusing again because it is taking snap shots of a voltage that is darting around a bit. I can only imagine these A/F meters you are using just takes that darting voltage and tempers it a bit so it makes more sense to the guy buying it. If you had a scope and new how to use one you cetainly could set it up to display and event that would show where the voltage was and when on a graph. The one I have is probably more than what you have into two scooter. though so like I said let's not go there. Yes O2 sensors can get contaminated so life would be shortened in a 2 stroke. However I have seen them pretty mucked up looking on oil burning car engines and still give pretty accurate readings. I am only suggesting someone give this a shot and it certainly could be done on the cheap and DIY. I have read a bunch of threads where someone is talking about soft seizing (what ever that is) and or holes in pistons so here is a solution to knowing where your A/F ratio is. I assume you guys are using expansion chamber exhausts. Does the scavanging of the combustion chamber pull raw fuel and air into the exhaust? My guess is probably not or you guys would all be riding around with glowing orange pipes. |
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Post by 90GTVert on Feb 22, 2011 8:56:47 GMT -5
A wideband has a wider voltage range. Some, like the Innovate model I mentioned, will calibrate themselves to open air to account for temp, altitude, and sensor degradation over time. I can also change voltage values and what AFR they coincide with if I so desire. The output is steady. No cross counting, sine looking, signal. With the right gauge or PC software, you just see the AFR in a steady form. Wideband O2s are what most dynos use these days. They are cool pieces and go well beyond what narrowband O2s can do. www.innovatemotorsports.com/resources/lm101.phpThe pipes do draw unburnt mixture into them. |
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Post by bigkahuna427 on Feb 22, 2011 9:32:12 GMT -5
So on your EECIV Mustang are you using this to monitor A/F or is this replacing the original O2? I am very familiar with electronic engine controls. Any change you make to the engine emission or fuel system would require a reprogramming of the controller (computer). That reprograming can come in a chip. So I guess if you bought a hop up package from one company and only made those mods than you would be assured to have the right programming and the best results. Take that same set up bolted onto a stock mustang and then add a different cam all bets are off. The same is for this wide band sensor. If the computer is supposed to see .1 to .9V than sees 1.5V which it is not programmed to see who knows what the result would be. However I would bet the folks that sold it to you will tell you. If this replaces a stock O2 than did it also come with a "chip"?
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Post by 90GTVert on Feb 22, 2011 13:33:28 GMT -5
It used to be EEC-IV for a long time. It did pretty well with the 331 and 30# injectors (19# was stock). When I went to turbo I had it dyno tuned and chipped, because it just couldn't seem to handle moving to 42# injectors otherwise. The main reason I went to a new setup for the computer was that dyno bills were too much. The initial dyno tune ran $1320. I was shocked to say the least, even more so when it came back on a rollback from blowing a head gasket on the dyno. When it needed another tune, it seemed like a better idea to just swap engine management setups to something that I could tune myself. Now it uses a Megasquirt setup. Widebands (among other sensors) tell it what is going on and it can data log and such. I can set the timing and fuel tables where I want them and the wideband data will help tell the computer what needs to happen. The stock O2s went in the garbage can.
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