Power FC Thinking of switching from 850/1600 to 550/1600
09-27-09, 12:30 PM
#27
My paper said it and FJO even responded to it. If your so doubtful you should give them a call. I have posted their e-mail where they said it was fine. When I e-mailed them I wasn't sure if all the injectors had to be high impedance or low, or if they could be mixed without issue.
I am not willing to do any testing of the sort. I was merely trying to point out if your so confident in your setup, you should try it. And that is exactly my point, the likelihood of it happening is small yes but the possibility will always be there no matter how you look at it.
Since it works like normal having it wired into high impedance primaries. There is no reason whatsoever to only do the secondaries since there is no downside to wiring them together.
I know without a doubt there is nothing wrong with boost cut if its done right. There was this one road coarse car I tuned that had a wastegate problem and fuel cut at least 10 times that day under WOT spiking to 18-20 PSi on pump gas (The car was tuned to run at 16 PSi). If fuel cutting was such an issue, the engine should have been toast. I have also hit 25 PSi on my own car due to a boost controller incorrect setting and fuel cut, again on pump gas and the motor is still perfectly fine. The only reason fuel cut is bad on the stock ECU is because if you reach at point, your already running lean to begin with.
thewird
Since it works like normal having it wired into high impedance primaries. There is no reason whatsoever to only do the secondaries since there is no downside to wiring them together.
I know without a doubt there is nothing wrong with boost cut if its done right. There was this one road coarse car I tuned that had a wastegate problem and fuel cut at least 10 times that day under WOT spiking to 18-20 PSi on pump gas (The car was tuned to run at 16 PSi). If fuel cutting was such an issue, the engine should have been toast. I have also hit 25 PSi on my own car due to a boost controller incorrect setting and fuel cut, again on pump gas and the motor is still perfectly fine. The only reason fuel cut is bad on the stock ECU is because if you reach at point, your already running lean to begin with.
thewird
The way that the unit is wired into the 12V power circuit of the injectors means that even with the driver only connected to the secondaries, if there is an interruption in the 12V constant, ALL injectors stop firing.
If you are incapable of grounding the unit correctly then you should not be doing any wiring on any vehicle.
This only leaves the driver circuits. You are saying that four completely independent circuits are all going to fail at exactly the same time. Exceedingly unlikely. Much more likely that only one will fail, which renders your theory for installing the driver on all four injectors utterly irrelevant.
The PFC injector driver does a great job firing high impedance injectors. Adding in another level of circuitry to a system that does not require it, is asking for a problem. Not to mention that by only utilizing two of the four circuits puts a lot less stress on the FJO, further reducing the likelihood of failure.
Your beloved fuel cut is controlled by the PFC not the FJO, using an over boost example to try to explain how an FJO failure will save your engine is ridiculous.
Here is the deal, you can do whatever you want to your car, I really do not care. I will continue to install the driver CORRECTLY as it was intended on the low impedance injectors. You can find someone else to start an argument with, maybe you will be able to convince them that you are right.
09-27-09, 06:30 PM
#30
Ive been having issues with high idle afr's on 850/1600's too. I get mid 13's on cold start but once its warm it goes way rich to mid to low 11's. Ive found that if I hit the ac button to on to bump up the cooling fan speed it idles up, then if I hit it again it idles back down to normal but the afr's also come down to low 13's. Im just not sure what cycling the ac button is actually affecting to make it do that. I do have my idle speeds set different for electrical load but before i push the button should be the same as what it is before pushing it on and then off. Anyone have any ideas whats going on? If I could get it to idle at low 13's on its own I would be happy.
09-28-09, 10:04 PM
#32
Here is another email from FJO regarding saturated injectors taken from this thread:
https://www.rx7club.com/showthread.p...+driver&page=7
So yes we are running them correctly. FJO also states in that email that there should be an increase in efficiency.
https://www.rx7club.com/showthread.p...+driver&page=7
I sent the following email to FJO tech support. I'm pretty surprised, I sent the email last night (Friday) at 11:45 pm and got a reply this morning at around 11:00am.
LOW IMPEDANCE INJECTOR DRIVER Q
I am interested in this product and have a few questions. In your product description, it states, "Reproduces ECU injector pulses in PEAK & HOLD format (4A/1A)". How can I expect the driver to react when using an injector that will not draw a current of 4 amps in the circuit?
For example, considering a 14V operating voltage, if I use an injector with an impedance of 5 ohms, 14 volts divided by 5 ohms of resistance would mean this circuit would draw 2.8 amps.
Would the driver apply no resistance to the circuit and allow 2.8 amps to flow for the peak stage? And for the hold stage, would the driver apply resistance to the circuit to achieve a lower current flow? If this is the case, how much current would be allowed to flow for the hold stage? Is it set to hold the injector open with 1 amp, or would it maintain the 4:1 ratio and only allow .7 amps?
Onto the next question. How long does the driver let peak current flow until switching to the hold current? Is the current dropped after a set time? The reason I ask this, is because when using very large injectors for very low loads and duty cycles (idle and low load driving), the injectors will be open for a very short amount of Ms's. For example, if your driver is set to drop to hold current after 2 milliseconds of peak operation, and at idle the injector is only open for 1 millisecond, then would only peak current be applied in this situation? This will be for a ported turbo rotary, so if idle conditions can be improved with more precise control, that would be a nice benefit.
LOW IMPEDANCE INJECTOR DRIVER Q
I am interested in this product and have a few questions. In your product description, it states, "Reproduces ECU injector pulses in PEAK & HOLD format (4A/1A)". How can I expect the driver to react when using an injector that will not draw a current of 4 amps in the circuit?
For example, considering a 14V operating voltage, if I use an injector with an impedance of 5 ohms, 14 volts divided by 5 ohms of resistance would mean this circuit would draw 2.8 amps.
Would the driver apply no resistance to the circuit and allow 2.8 amps to flow for the peak stage? And for the hold stage, would the driver apply resistance to the circuit to achieve a lower current flow? If this is the case, how much current would be allowed to flow for the hold stage? Is it set to hold the injector open with 1 amp, or would it maintain the 4:1 ratio and only allow .7 amps?
Onto the next question. How long does the driver let peak current flow until switching to the hold current? Is the current dropped after a set time? The reason I ask this, is because when using very large injectors for very low loads and duty cycles (idle and low load driving), the injectors will be open for a very short amount of Ms's. For example, if your driver is set to drop to hold current after 2 milliseconds of peak operation, and at idle the injector is only open for 1 millisecond, then would only peak current be applied in this situation? This will be for a ported turbo rotary, so if idle conditions can be improved with more precise control, that would be a nice benefit.
And this was the reply:
The KID0404 uses a complex algorithym to determine when it transittions from peak to hold mode. I hope you can appreciate that we do not publish details on the inner workings of our products as this is considered proprietary. However, I can say that the device will drive higher impedance injectors more effectively than most ECU's. The device does not do a 4:1 current limit but rather 4A and 1A independantly because limiting the current is not function of applying inline resistance. Obviously if the injector you are using doesn't draw 4A then it becomes the current limiter and not the driver. Unlike other drivers or some ECU's, the KID0404 has a very sophisticated method of determining when to transition from Peak to Hold. The design also takes into consideration that you are switching a coil on and off and not just a resistive load. They are different and this is where the KID0404 can really make a difference when tuning low duty cycles. This applies to low and high impedance injectors. The box was designed for racing applications that require high flow injectors, yet still offer tunability at very low load conditions. Because the KID0404 can drive 4 injectors independantly it is possible to mix injector types (low/high impedance). KID0404 MSRP $149.95
Technical Support
The KID0404 uses a complex algorithym to determine when it transittions from peak to hold mode. I hope you can appreciate that we do not publish details on the inner workings of our products as this is considered proprietary. However, I can say that the device will drive higher impedance injectors more effectively than most ECU's. The device does not do a 4:1 current limit but rather 4A and 1A independantly because limiting the current is not function of applying inline resistance. Obviously if the injector you are using doesn't draw 4A then it becomes the current limiter and not the driver. Unlike other drivers or some ECU's, the KID0404 has a very sophisticated method of determining when to transition from Peak to Hold. The design also takes into consideration that you are switching a coil on and off and not just a resistive load. They are different and this is where the KID0404 can really make a difference when tuning low duty cycles. This applies to low and high impedance injectors. The box was designed for racing applications that require high flow injectors, yet still offer tunability at very low load conditions. Because the KID0404 can drive 4 injectors independantly it is possible to mix injector types (low/high impedance). KID0404 MSRP $149.95
Technical Support
09-30-09, 03:05 PM
#35
To the original question. yes you can run 550/1680, I run them on my car and push over 500 hp. I also have dual fuel pumps and slightly higher base pressure. Adding the second pump dropped my duty cycle quite a bit.
Running 23 psi with large street port and t70 I see a peak duty cycle of 80. afrs 10.8-11
Running 23 psi with large street port and t70 I see a peak duty cycle of 80. afrs 10.8-11
11-07-09, 05:04 PM
#38
Augh, after spending some time with it today I cannot get my p04 cells leaner. I thought this was due to having the 850 injectors. Switching to 550's has had not effect on lowering AFR's in high vacuum cruise. My p04 cruise areas are at about 11.2:1 This is annoying. I have .0 lag and I've played around with the secondary engagement percentage . Why is this still happening? However I can get my idle to 14.7:1 with no problems.
11-09-09, 12:37 AM
#41
Your never going to be able to get rid of it completely, every car has it. You might be able to improve it a little by opening the air screw underneath the throttle body. Also, make sure your TPS is within spec. Normally cars with 550's will do 12's at the lightest possible point on the throttle.
thewird
thewird
11-09-09, 09:55 AM
#42
Augh, after spending some time with it today I cannot get my p04 cells leaner. I thought this was due to having the 850 injectors. Switching to 550's has had not effect on lowering AFR's in high vacuum cruise. My p04 cruise areas are at about 11.2:1 This is annoying. I have .0 lag and I've played around with the secondary engagement percentage . Why is this still happening? However I can get my idle to 14.7:1 with no problems.
My car with light throttle inputs will go as lean as I want. It will hesitate if I go too lean. I usually aim for 14 or so in low speed conditions and as lean as the car will handle in speeds over 40.
11-09-09, 09:58 AM
#43
Maybe you should post your map so everyone is on the same page. I saw Aeka GSR's map from the tuning group. He's running pretty lean and I think he went too far on the high vacuum cells for it to be smooth. But then again I've never messed with a half-bridge so I'm not 100% sure.
thewird
thewird
11-09-09, 05:05 PM
#45
Here is the map. To make sure it wasn't some variable by the TPS I gave it throttle in neutral to bring it up to the same cells of question, while holding it there I took away all the fuel i could in the cell and surrounding cells. Nothing happened so I went ahead and added a negative value to the injectors. I went as far as -.04 and it did nothing.
Chuck seems to think I have leaky injectors but I haven't had any startup issues and these injectors came off my other engine that was stock and working flawlessly but anything can happen.
Chuck seems to think I have leaky injectors but I haven't had any startup issues and these injectors came off my other engine that was stock and working flawlessly but anything can happen.