LowZ vs HighZ and the relay board

[66brm]

Ok I've been reading the hell out of the manuals of late for my MS2 3.57 install, I have 41lb lowZ injectors and have found in the hardware manual that its not recommended to run LowZ injectors from the relay board, any idea why? Also whats the general consensus on how to run with lowZ injectors, PWM, resistors or external driver? Or just spend another $220 on a set of highZ injectors and be done with it?

[Clonebug]

I've been running Low Z 32# injectors for 2 yrs on my relay board.

[66brm]

How are you controlling the injectors? PWM?

[Piledriver]

It's software PWM capable, but there may be a required flyback diode mod, might just be needed for the 2.2 boards.

If you ever want sequential, JBPerformance sells a hardware PWM 4 channel injector driver board.
Used one on my original MS2 a few years ago, thought I might need lowZ but never needed to go there.
Sadly the *4x4 (ign+inj) "4 channel board" appeared later, or I would have just used that.

I stuck the driver board and ign boards in a separate MS1 case.
(The MS2 went in an MS3 case, had just become available)

These days you can use an MS3x with a MS2.

Of course the sequential injector lines will have to bypass the relay board, as it only has the two B&G inj wire pairs.

The $50`08 GSXR600 ITB set I picked up had 4x230 cc tan and 4x440cc gray pico injectors in it, as well as 2 usable TPS and a NA MAP sensor, and the $10 electrical harness provided 8 nice connectors to match the injectors and the TPSs etc. The ITBs ended up much better than free, as all those injectors and other bits were clean and perfect.


(*there is also a "4 channel board" that has 4 ign drivers as well, but it cannot do lowZ inj PWM)

[miniman82]

No issues with low Z squirters in batch mode, but like Pile said you can't do sequential fuel with the relay board because of the channel limitations (only 2).

[Clonebug]

I asked Mario what I need to do to run High Z since my 32# injectors are maxed out.

He said it is all adjusted in Tunerstudio with my 3.0 version board so if you can probably set your 3.57 board up the same way.

How it is done???..... I will probably just let him tweak my *.msq for me.....

[66brm]

I wonder then if it can be done why the manual says its not recommended, I'm not intending on going sequential so I'll try the board and see how it goes, as per the method of control, I think I can understand the PWM settings and how to adjust so will give it a go initially, whats the worst that can happen I just need to mod the board for flex fuel etc and nearly time for a trial run before the body goes back on the 57

[miniman82]

Perhaps the relay board traces can't maintain high opening current for very long so they don't recommend it? I doubt you'll have any problems, a lot of people are doing it.

[66brm]

Strangely enough that was my exact thought as well, If I have an issue I can run a couple of jumpers across

[damo99]

66brm - there is a facebook page for megasquirt in australia it's at
https://www.facebook.com/groups/462050220641132/
theres quit a few dubbers on there

[66brm]

Nice cheers