Yes, JB4 (With the JB4 PI controller) is able to control both Stage3 Lpfp and the Port Injection. You don´t need the Hobb switch to do that.
PI controller pro's & Con's comparison: JB4 PI vs split 6
- Thread starter TurboMike
- Start date
Yes, JB4 (With the JB4 PI controller) is able to control both Stage3 Lpfp and the Port Injection. You don´t need the Hobb switch to do that.
By control basically it means turn on the pump and turn on progressively the PI and a bank AFR safety but nothing regarding individual injector control coordinated with DME individual injector control which would be neccesary for misfire protection when the DME shuts down a cylinder.
We just did a GC install with a ton of fuel stuff as well. The guy wanted JB4, we planned to have the JB control the LPFP, and the PI. It was not working as it should. Terry himself suggested we do not control the pump with the JB, to use a Hobbs switch. I personally do not like the JB4 PI controller, you have little control over it basically. As basic as the AIC6 is, you still have control over what the PI is doing, well in our case, what the secondary HPFP is doing. Honestly using the AIC6 to control the extra HPFP makes everything so simple.
Now was the issue because you you were using the second hpfp instead of PI? I guess I'm saying if the setup was just a stage 3 fuel kit and PI would you still feel the same way? I thought the jb4 controller gave you more tuning ability then the aic6
Huh? The car has PI on it, as I stated we wanted to control the PI, and LPFP. It would not control the fuel pump properly, we kept having issues. Terry suggested using a Hobbs Switch, and just letting the controller do the PI. As I said not a huge fan. It does work, it seems to work ok, but you really have no control. How would you have more control? You can no longer log PI events separately to watch IJPW, You can no longer tailor your RPM/Boost table for exactly where you do or do not want fuel. Basically all you can do is just set global settings for adding fuel, in the "fuel bias" column, then you hope it does what you want. We tuned another 535 with GC's and JB4, we had a hell of a time getting it right, it just wanted to go rich all the time. If you are hands off person, the JB4 controller is fine, but I prefer more control.
From the FAQ on the BMS/Fuel-IT Port Injection thread:
http://www.n54tech.com/forums/showthread.php?t=28478
http://www.n54tech.com/forums/showthread.php?t=28478
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Until the system can monitor HPFP, and adds fuel to keep that up its a bunch of smoke, and mirrors. So you it monitors lpfp as a parameter of when you need PI? Care to explain the logic behind that. You can have plenty of LPFP pressure, and need much more PI to be injected to keep rail pressures where they need to be. As I stated you literally have one column of values you can enter, then the controller monitors in my opinion parameters that are little value to rail pressure needs. With the AIC6, you have full control. You see rail pressure dipping at certain RPM / Boost level etc. You can add fuel EXACTLY where its needed to keep rail pressure up. Until the JB controller can monitor rail pressure, and inject based off that, it offers limited control in my opinion. As I stated before, we have used it, it works fine. We shipped a car making 660WHP back to its own with the system in place, no issues. But for my own stuff, I like more control, as well as the ability to log IPW etc. My $02 cents, take it for what its worth.
They monitor lpfp on the jb4 box since the PI fuel volume will decrease when lpfp pressure drops, so they increase ipw to compensate. In the other systems the hpfp would just pick up the slack, which works perfectly fine. I wouldn't really consider that point a great feature, but it is something and it's not a bad thing.
Issues with all of these systems are the same. None of them can turn off individual injectors when the DME shuts off an injector (IE- misfires). These basic controllers are not advanced enough to offer individual injector control to begin with. Even if the jb4 could add logic or additional wiring to sense fuel cut at the level of the DI injector, the delay may still be too long without a stand alone like the syvecs. This has claimed motors with all controllers. And yes, this was similar with meth, but for one meth has claimed many motors as well, and the amount of energy (fuel) injected with meth was much lower and the octane was much higher.
Issues with all of these systems are the same. None of them can turn off individual injectors when the DME shuts off an injector (IE- misfires). These basic controllers are not advanced enough to offer individual injector control to begin with. Even if the jb4 could add logic or additional wiring to sense fuel cut at the level of the DI injector, the delay may still be too long without a stand alone like the syvecs. This has claimed motors with all controllers. And yes, this was similar with meth, but for one meth has claimed many motors as well, and the amount of energy (fuel) injected with meth was much lower and the octane was much higher.
I'm sorry I misread I thought you were using the double barrel system. Probably had previously read that thread before this one.
I'm in the midst of trying to decide if I want to pull the jb4 out also when I pull the meth kit out and go flash only with the split6 controller or just pull the meth out and utilize the jb4 and the jb4 PI controller.
Aiming for 775-850whp on full e85. Fueling will be EOS manifold, PR stage 3 lpfp, fuel it upgraded lines, ethanol sensor, ethanol analyzer, FPR with return line.
It sounds like I'll also have to add the Hobbs switch to the mix aswell from your feedback tony.
I prefer mapping the SS rather than using the Jb4 to control the pi. The jb4 control seems inconsistent from my experiences. I like knowing exactly how much I'm commanding as well.
The AIC6 itself has only access to boost and engine speed so it's very limited in what it can do. You might think you are in full control but with such a limited data set you're really just fooling yourself. Read up on what the JB4 PI control can do which
includes cutting fueling during a misfire, during sudden transitions, flexing port injected fuel up during tip in and transitions, and so much more that is currently under development. Without a JB4 running PI you can't even detect a bank to bank trim variance automatically and cut PI flow and boost before its too late...
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That's all well and good in theory, but there are now multiple occurrences where it just don't work. Quite a few ST cars had to revert back to a regular AIC because the JB4 control was causing a ton of fueling issues with their cars. Also, what is Terry using to detect a misfire the instant it happens and not way after when a code is thrown? Last I heard he couldn't do it.
I've never heard of someone having a problem they were not able to
work with BMS to sort out easily. Most of the problems come from
people using old hardware like a JB4 board with old firmware/drivers
that isn't compatible with the new stuff. In one case I heard of a
defective PI controller box that would not turn on and not feed an
"everything is OK" signal to the JB4 so they had to swap it out for
the customer.
On how certain things work technically you'd have to discuss with
Terry but with the JB4 normally as fast as we can describe something
he can come up with a way to implement via JB4 since the system is so
flexible.
Hey guys, Payam told me about this thread so I decided to check it out. I'll chime in from time to time as time permits on any questions on the setup. JB4 port injection integration is something we've spent a good amount of time on and its definitely an area of active development!
PS. The JB4 + PI solution can detect and failsafe if you are unlucky enough to have this happen. Good luck catching this automatically without a JB4.
View attachment 1790
Theres other way more advanced PI controllers in the works. I know of several .
You can control a 2nd fuel pump with the JB4, unless you are using the extra JB4 high current output for the 2STEP/NLS relay, in which case then you need a Hobbs switch. We'll be adding a high current output to the BMS PI controller at some point soon to trigger a second pump. We need it to trigger the meth pumps for direct injection meth anyway.
