wondersparrow Posted October 2, 2009 Share Posted October 2, 2009 Something John C said a while ago has me intrigued..... Uuuhhhh, timing and fuel are separate items. You can have a knock sensor and a crank trigger as input to computer controlled timing on a Weber Carb'd L24 and achieve exactly what you're describing above. Been there, done that - although its so 1980s. I am really enjoying working with my triple webers in my track car. It has been an interesting challenge as they really are the first carbs I have worked with. I have been planning on installing an EDIS system and a wideband over this next winter (once the catastrophic oil burning issue is fixed). I had planned on using a megajolt system, but now I am wondering if there is a way to add a knock sensor. I have run into the Polestar ignition systems for Minis. I haven't yet inquired if they will work on a 6 cyl yet, but they seem prohibitively pricey anyway. Has anyone seen megajolt augmented with a knock sensor before? Does anyone know of other ignition systems that support a knock sensor? I know, I know, efi would be cheaper and more reliable in the long run. It is inevitable, but as long as I am still a noobie at racing and not jockeying for the top spots, I don’t mind taking the time to do things in stages. Maybe I enjoy the tinkering, hehe. When I decide to get rid of the l24, I will go efi for sure. Thanks in advance for entertaining my curiosity Quote Link to comment Share on other sites More sharing options...
josh817 Posted October 7, 2009 Share Posted October 7, 2009 I PM'd this to you: I asked around but no one knows seems to know the voltage for the sensor. One way I guess you could do it is to get a hammer and tap the sensor, try to get a reading for it. Once you find the voltage, its easy to hook up. One wire which is the + or signal, sensor grounds to the block. Then all thats left is to either auto calibrate, or figure out what voltage the knock sensors sends out when there is some pinging. From their site: User out = 0-1v input. AUX input is a 0-5v http://www.autosportlabs.net/MJLJ_V4_vehicle_installation_guide If you auto calibrate I'm guessing it will want to find your max and min voltage which means you shouldn't ping and then you should ping a ton or something. I didn't bother reading the 0-1v input part so the link is there for you guess. Theres also an operational guide. Quote Link to comment Share on other sites More sharing options...
wondersparrow Posted October 7, 2009 Author Share Posted October 7, 2009 That site implies that the outs are just that, outputs. I am assuming they would be used for things like external fans, indicator lights, things like that. I guess the aux in would be the one to use. Quote Link to comment Share on other sites More sharing options...
josh817 Posted October 7, 2009 Share Posted October 7, 2009 Yah I think I had that mixed up. You're right about the output thing. The Aux input is by default a 0-1v signal however you can make it a 0-5v signal input by cutting the trace to "R6". So I guess that means for me that I won't be able to run a knock sensor and wideband. D: Unless I can tune the ignition and then do AFR. Who knows. Quote Link to comment Share on other sites More sharing options...
wondersparrow Posted October 7, 2009 Author Share Posted October 7, 2009 Are you actually adjusting the spark using the wideband? I wonder which would be more valueable, afr or knock? knock seems like it would help under a more varied range of conditions as opposed to just rich/lean. Though knock seems like it might be a bit trickier to program. I may be wrong in my assumptions, but a knock sensor seems like more of a digital sensor. There is either knock or there isn't. Does anyone know if a knock sensors output is analog and therefore can detect the severity? Quote Link to comment Share on other sites More sharing options...
josh817 Posted October 7, 2009 Share Posted October 7, 2009 Are you actually adjusting the spark using the wideband? I wonder which would be more valueable, afr or knock? knock seems like it would help under a more varied range of conditions as opposed to just rich/lean. Though knock seems like it might be a bit trickier to program. I may be wrong in my assumptions, but a knock sensor seems like more of a digital sensor. There is either knock or there isn't. Does anyone know if a knock sensors output is analog and therefore can detect the severity? No I'm going to use it to tune the triple webers since they're a pain to tune. Quote Link to comment Share on other sites More sharing options...
wondersparrow Posted October 7, 2009 Author Share Posted October 7, 2009 I guess at that point, I don't see the need to have it actually hooked up to the MJ system. I plan on putting a wideband on mine as well, but I am just going to get an autometer gauge for it. I was thinking of using a led for knock, but if i can figure out how to actually have MJ retard the timing when there is knock, that would be preferred. I wonder if one could just put in a rheostat or knob that would allow you to advance and retard the timing manually from inside the car. That could work too. Have a wideband gauge and an indicator light hooked up to a knock sensor. Then just let the driver (me ) control the timing manually. Gears turning....schemes developing.... Quote Link to comment Share on other sites More sharing options...
josh817 Posted October 8, 2009 Share Posted October 8, 2009 That sounds like a cool idea however with MJ they give you a 10x10 graph. By twisting a knob, how does it know what RPM and Load "box" to adjust? I don't want a gauge because I want a graph of the wideband with the RPM, TPS, and Advance. They give you like RPM acceleration and all that stuff too but I took that off the graph so its less cluttered. I've talked to... myself... about the idea for a while because once the AFR is set, you shouldn't have any problems unless you go somewhere with a different altitude or something. I'd figure out my cold weather tune and my hot weather tune and then be done with it. Therefore the question is, why would I keep a sensor in there and let its life span tick away when I'm not using it. I won't be using a gauge for it because I'm keeping to all stock gauge for now. I'm not a big gauge dude so I don't like a ton of them all over the place. If I switched to autometer I'd get the speedo, tach, fuel, oil pressure, and water temp. Quote Link to comment Share on other sites More sharing options...
wondersparrow Posted October 8, 2009 Author Share Posted October 8, 2009 Ah yeah, this is for my track car, so random gauges and indicators arent as annoying, hehe. I am pretty sure mj has an advance correction thing that you can calibrate. Usually used for things like water temp. I see no reason you cant just put in some sort of nob in place of a temp gauge that outputs voltages in the appropriate range. It appears it can be calibrated as well, so should be a snap. a 0-1v knob should be easy to find. Quote Link to comment Share on other sites More sharing options...
wondersparrow Posted October 9, 2009 Author Share Posted October 9, 2009 http://www.turboxs.com/more_info.php?ID=212 not that pricey and solves the rpm/noise issue. Quote Link to comment Share on other sites More sharing options...
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