impellerhead Posted July 20, 2009 Report Posted July 20, 2009 We are having problems getting the injector staging right on my 4 cylinder methanol turbo engine, I have 4 1680 bosch 842 injectors as primary injectors and 8 bosch 846 as secondary. All injectors have ballast resistors connected. The secondaries are wired in pairs. We disconnected 4 of the secondary injectors so that we had 4 + 4 and then we set sec/pri ratio to 1 and got it working perfect, but with all 8 connected on the secondary with sec/pri ratio 2 the engine runs lean when it has staged the secondarys in. Here is my settings: http://www.impellerheadz.com/link/Volvon2009Metanol.pcl Please help I need to get this working soon!! Quote
impellerhead Posted July 20, 2009 Author Report Posted July 20, 2009 The secondary injectors are paired and each pair share a ballast resistor, I don't know if that is the right way to do it? Could this be a cause to the problem? Quote
Simon Posted July 21, 2009 Report Posted July 21, 2009 How do you have the 8 secondarys wired? Are they in parallel or series? What resistance are the injectors measuring and what value ballast resistor have you used? Quote
impellerhead Posted July 21, 2009 Author Report Posted July 21, 2009 The injectors are parallell and the resistor is in series with the two parallell injectors. The resistance on each injector is about 5 ohms, resistor used is 4.7 ohms. Quote
impellerhead Posted July 21, 2009 Author Report Posted July 21, 2009 Anyone? The engine is sitting in the dyno and waiting for a solution to this problem. Please help me! Should I have a resistor for each injector instead? and If so what ohm? Or should i wire the injectors in series instead? Quote
impellerhead Posted July 21, 2009 Author Report Posted July 21, 2009 Or is it maybe the that the injector dead time must be adjusted for the secondarys? Quote
Guest Dave Posted July 21, 2009 Report Posted July 21, 2009 HI I have replied to Roger at motornord directly and am waiting for a copy of the pcl file as I cannot open the link above for some reason Regards Dave [email protected] Quote
impellerhead Posted July 21, 2009 Author Report Posted July 21, 2009 Weird that the pcl file didn't work, I will talk to Roger tomorrow and re-save the pcl file to see if it works this time. Feel free to email me on [email protected]. Regards / Fredrik Quote
impellerhead Posted July 21, 2009 Author Report Posted July 21, 2009 I really hope we get this working soon, We have dynoed 264hp without the turbo on methanol at 8500 rpm. Now the turbo is waiting to do its work as soon we get the secondary injectors to play along. Quote
impellerhead Posted July 21, 2009 Author Report Posted July 21, 2009 I really hope we get this working soon, We have dynoed 264hp without the turbo on methanol at 8500 rpm. Now the turbo is waiting to do its work as soon we get the secondary injectors to play along. Quote
ashesman Posted July 22, 2009 Report Posted July 22, 2009 I havn't really paid too much attention to what is going on here. But here are some points to note: Putting injectors in parallel does not change their dead time. Putting a resistor in series (with one or two injectors) does alter (increase) the deadtime as the effective applied voltage to the injectors is lower. At 14 volts battery voltage you have 1 amp per injector (two 5 ohm injectors in parallel in series with 4.7 Ohm). 1 Amp will be enough to hold the injetcors open but may not be enough to open them if high fuel pressure is used. Consult injector manufacturer data sheets for an answer. The pri/sec ratio is a flow ratio. Claculate the total flow from your primaries (at the used fuel pressure) and secondaries and work out the ratio using the equation given in the help. I dont think 2:1 will be correct. Quote
Guest Dave Posted July 22, 2009 Report Posted July 22, 2009 Just read through this whole post again and you are using two different types of injector the 842 was designed by bosch as a cng injector designed to operate at 1 bar pressure with gas and yes can flow 1680cc at 3bar on petrol the 846 injector is a methanol injector and flows 1680cc but that is at 100% duty cycle ie hard on the flows at lower duty cycles could be quite different between the 2 types you would need to run them on a flow bench to confirm this and this would have quite an effect on how they staged Regards Dave [email protected] Quote
impellerhead Posted July 22, 2009 Author Report Posted July 22, 2009 But it works when we run it with 4 of the 842's and 4 of the 846's, the lambda is ok. It's when we have all 8 846's connected on the secondary it doesn't work. Quote
impellerhead Posted July 22, 2009 Author Report Posted July 22, 2009 What I want to know right now is do I have to change the resistor or add another to get it working properly? Quote
impellerhead Posted July 22, 2009 Author Report Posted July 22, 2009 because I don't have any more resistors and have to order them in that case and have to wait for them before we can run the engine more on the dyno, that's why I want to know if this is a problem with the resistor or if it is a problem with the settings. But you say it's the settings? Quote
impellerhead Posted July 22, 2009 Author Report Posted July 22, 2009 We had an 'injector dyno night' tonight. We hooked up a computer with a Signal Generator to the triggers so that we could run the injection without starting the engine. Then we mounted a fuelrail with 1 '842' injector and 2 '846' injectors. First we ran at 3mS dutycycle With one 842 and one 846, each serial connected to 4.7ohm resistor they gave exactly the same amount fuel sec/pri 1:1. So they are the same size. Then we parallel connected 2 '846' secondary injectors to 4.7ohm resistor. Sec/Pri ratio 2:1 still running 1 '842' on the primary with 4.7ohm, We tried to spray about the same amount in the bottles each time. We had 411gram in the primary bottle, 284+266 in secondary bottles=550. 411x2=800 800-550=272grams too little coming out of the secondaries! Way off... Now we parallelconnected 2 4.7ohm resistors on the secondaries so we had 2.35ohm in series with the 2 secondary injectors. This time we had only 47grams too little in the secondary bottles. We then increased the deadtime +0.1 and now we had exactly double amount coming out of the secondarys. So the we increased to 10mS dutycycle, now we had 45 grams too little out of secondarys. Adjusted back deadtime to standard setting and adjusted sec/pri to 1.9 and had 16 grams too little, so thats pretty close to the truth. Tried same settings with 3mS dutycyle and had 7 grams to little. So now I'm only waiting for my new resistors and we'll get the engine running as it should! Quote
impellerhead Posted July 24, 2009 Author Report Posted July 24, 2009 At last we got the engine fully tuned, 1020hp at 7500rpm and 1030Nm(760 lb/ft) torque at 6000rpm with 3 bar (43psi) boost. Quote
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