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Megasquirt advice.........Injector Staging
Bumble - 2/8/10 at 01:38 PM

In engine constants my injector staging is set to "Simultaneous" as opposed to "Alternating". I have a 1.8 Zetec on R6 Tb's and this was the base map loaded from Phil at Extra EFi. Which is correct for my set up?
Thanks,
Matt


MakeEverything - 2/8/10 at 03:45 PM

Start off at Simultaneous. you can always change it later. It depends on how you've wired the plugs from the coil pack, and depending on your firing order. In theory, what it does is uses all of the high tension voltage on four plugs or two at a time.

quote:
Originally posted by Bumble
In engine constants my injector staging is set to "Simultaneous" as opposed to "Alternating". I have a 1.8 Zetec on R6 Tb's and this was the base map loaded from Phil at Extra EFi. Which is correct for my set up?
Thanks,
Matt


matt_claydon - 2/8/10 at 04:05 PM

quote:
Originally posted by MakeEverything
Start off at Simultaneous. you can always change it later. It depends on how you've wired the plugs from the coil pack, and depending on your firing order. In theory, what it does is uses all of the high tension voltage on four plugs or two at a time.

quote:
Originally posted by Bumble
In engine constants my injector staging is set to "Simultaneous" as opposed to "Alternating". I have a 1.8 Zetec on R6 Tb's and this was the base map loaded from Phil at Extra EFi. Which is correct for my set up?
Thanks,
Matt



Injector staging has nothing to do with ignition, it's about whether all four injectors fire together, or in pairs of two. To answer the OP, it really doesn't matter for most people, I'd just leave it how it is.


t16turbotone - 2/8/10 at 04:38 PM

Injector staging has nothing to do with ignition, it's about whether all four injectors fire together, or in pairs of two. To answer the OP, it really doesn't matter for most people, I'd just leave it how it is.
...CORRECT


coyoteboy - 11/8/10 at 12:06 AM

To expand...

The MS has two injector driver circuits, most people fire 2 injectors from each, usually 1 and 3, 2 and 4. However both can be fired at once (simultaneous) or alternating. The same amount of fuel is injected (in theory) however in sim mode one of the cyls is left with its fuel in the port for 3 strokes, and one injected on the intake stroke. This naturally gives a bit of variability in charge quality. Most engines won't care much, at a scale we can see/measure, but some (especially sensitive, bike engines, ones on the edge of stalling at idle due to cams etc) may find it important. My 3S-GTE is notably smoother at idle with alternating, but by far the most important difference is fuel pressure. Firing simultaneous mode drops the fuel through all 4 injectors at once, this means a fairly large pressure drop on the rail, which can mean less fuel delivered than intended. Alternating helps this by halving the instantaneous flow rate.



[Edited on 11/8/10 by coyoteboy]