DuoWing Posted May 27, 2009 Share Posted May 27, 2009 Alright I installed a Nistune board into an 89' Z31 ECU N/A. It's now set to run with 88-89 Z31T fuel maps and timing, etc. Anyway I see since I'm using it on my 280ZX harness that I need dropping resistors for the injectors. I saw on a writeup on XenonZ31.com that it shows to use 6-10ohm 10Watt wirewound dropping resistors. I went to radioshack and all they had were 10ohm/10 watt resistors. I assume this is fine, but I see JWT uses 6.8ohm/10 watt resistors. Can anyone chime in and let me know if using 10ohm/10 watt resistors will be ok? Quote Link to comment Share on other sites More sharing options...
TODD0341 Posted June 7, 2009 Share Posted June 7, 2009 I was hoping I would be the first person in Cleveland with Nistune HAHAHAHA The lower ohm is to control the duty cycle of the injectors as an initial starting point in tuning the ecu, are they the stock injectors? I would assume you are running the car in sequential operation, if so, you can back the duty cycle down with the Nistune. I have an 87 turbo I just swapped a t-5 and rebuilt turbo motor into, I am hunting for another ecu to drive on so I can install Nistune. If you need any help tuning it, please let me know - I would love to check out the program and see what I am getting into! I live in Parma. Quote Link to comment Share on other sites More sharing options...
jeffp Posted July 4, 2009 Share Posted July 4, 2009 The resistors are used for the low impedance injectors (peek-hold type). Dropping resistors as you mentioned ar installed to lower the CURRENT to the injector, not so much for the injector, but to protect the driver transistors in the ECU. The resistors do not control the duty cycle of the ECU, the Latency, fuel map, and the K value control the duty cycle. < The lower ohm is to control the duty cycle of the injectors as an initial starting point in tuning the ecu, are they the stock injectors? I would assume you are running the car in sequential operation, if so, you can back the duty cycle down with the Nistune.> The Z31 box does not operate in sequential mode of operation, but rather batch fire ONLY. Also for the L28 and wire harness, you need to swap injector #2 wire @ the ECU with injector #5 to seperate each bank to their proper injectors. The Z31 box have ONLY two drivers, so three injectors are connected to each transistor in the ECU. Since you have gotten some information that is not correct, the resistors you need can not be WIREWOUND components. The wire wound parts add an inductive component to the driver circuit and they will affect how the injector behaves. You need AUDIO resistors. Digikey sells exactly what you need resistor part # MRA12-resistor value-ND so the part number will be MRA12-5.0-ND resistor values available: 2.0,2.5,3.0,3.5,4.0,5.0,6.0,7.0,8.0,10.0, and higher, but you don't need them. digikey telephone # (800) 344-4539 And since you mention it, I have done some work with Clark at JWT and we found we could drive the injectors harder with the lower resistors more along 3.0 OHMS. What you get with the higher current is a faster response time regarding the LATENCY (or time from off to a fully open injector) this becomes important as you increase the size of the injectors. Larger injectors are generally a slower responding injector then the smaller injectors. You will need to rescale the fuel maps, the timing map, the cold start, warmstart, first time start. Don't play with the dwell time and dwell duty unless you need to as a last resort. I also have setup a bench and I can tell you if you start messing with them you will get to a point that the power transistor is working to hard (for the coil) and will burn out. So unless you have an ocsope to probe the coil primary side to determine when and what time it takes to saturate the coil you are better off not messing with them. GUYS> if you are going to give information out about this stuff, make DAMN sure you know what you are talking about! The poster asked a question because he did not know the answers, that is why it was asked. He got information that was incorrect and very easily have caused him some serious problems with his steup, was that helpful? I think not. Quote Link to comment Share on other sites More sharing options...
DeleriousZ Posted July 7, 2009 Share Posted July 7, 2009 The resistors are used for the low impedance injectors (peek-hold type). Dropping resistors as you mentioned ar installed to lower the CURRENT to the injector, not so much for the injector, but to protect the driver transistors in the ECU. The resistors do not control the duty cycle of the ECU, the Latency, fuel map, and the K value control the duty cycle. < The lower ohm is to control the duty cycle of the injectors as an initial starting point in tuning the ecu, are they the stock injectors? I would assume you are running the car in sequential operation, if so, you can back the duty cycle down with the Nistune.> The Z31 box does not operate in sequential mode of operation, but rather batch fire ONLY. Also for the L28 and wire harness, you need to swap injector #2 wire @ the ECU with injector #5 to seperate each bank to their proper injectors. The Z31 box have ONLY two drivers, so three injectors are connected to each transistor in the ECU. Since you have gotten some information that is not correct, the resistors you need can not be WIREWOUND components. The wire wound parts add an inductive component to the driver circuit and they will affect how the injector behaves. You need AUDIO resistors. Digikey sells exactly what you need resistor part # MRA12-resistor value-ND so the part number will be MRA12-5.0-ND resistor values available: 2.0,2.5,3.0,3.5,4.0,5.0,6.0,7.0,8.0,10.0, and higher, but you don't need them. digikey telephone # (800) 344-4539 And since you mention it, I have done some work with Clark at JWT and we found we could drive the injectors harder with the lower resistors more along 3.0 OHMS. What you get with the higher current is a faster response time regarding the LATENCY (or time from off to a fully open injector) this becomes important as you increase the size of the injectors. Larger injectors are generally a slower responding injector then the smaller injectors. You will need to rescale the fuel maps, the timing map, the cold start, warmstart, first time start. Don't play with the dwell time and dwell duty unless you need to as a last resort. I also have setup a bench and I can tell you if you start messing with them you will get to a point that the power transistor is working to hard (for the coil) and will burn out. So unless you have an ocsope to probe the coil primary side to determine when and what time it takes to saturate the coil you are better off not messing with them. GUYS> if you are going to give information out about this stuff, make DAMN sure you know what you are talking about! The poster asked a question because he did not know the answers, that is why it was asked. He got information that was incorrect and very easily have caused him some serious problems with his steup, was that helpful? I think not. Great info!! Quote Link to comment Share on other sites More sharing options...
TODD0341 Posted July 8, 2009 Share Posted July 8, 2009 This is me from not reading enough on the Nistune Forums..... Quote Link to comment Share on other sites More sharing options...
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