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-   -   Squirts Per Engine Cycle? (https://www.miataturbo.net/megasquirt-18/squirts-per-engine-cycle-44015/)

Chris Swearingen 02-17-2010 07:16 PM

Squirts Per Engine Cycle?
 
In an attempt to idle at something leaner than 11.x to 1, I am wondering if I can change the squirts per engine cycle from 2 - alternating to 1 - simultaneous.


Injector Staging - simultaneous fires all injectors each injection event, alternating fires only half the injectors on one injection event, then the other half on the next event.

My thought is, that this will allow a longer opening time and thus better control over the amount of fuel that the 750cc injector is delivering. 1.8 ms is not very long for a pulse width. If I am twice per cycle that is .9 ms per squirt right? Or am I totally confused and I should be going to 4 squirts per cycle? Or is 2 the best solution?

What else do I effect when I do this? Is the puddle size or fuel on the wall going to be different for enrichment purposes? (Not that I have that tuned well anyway)

Is this a bad idea? Or will it not even work?
Anyone have thoughts on the matter?

Chris Swearingen 02-17-2010 07:46 PM


Originally Posted by The MegaManual
In the tuning software, the upper REQ_FUEL box is the amount per cylinder, as noted above. The lower REQ_FUEL box is the downloaded value to the ECU - this is the REQ_FUEL number on top, but scaled by your injection mode (number of squirts and alternate/simultaneous). For example, if you inject simultaneous and one injection, and have the same number of injectors as cylinders [i.e. port injection], then REQ_FUEL on the bottom is the same as REQ_FUEL on top. Same with alternate and two squirts. If you put in simultaneous and two squirts, then REQ_FUEL is divided in half - because you squirt twice, you need to inject 1/2 the fuel on each shot.

So 1 squirt simultaneous and 2 squirts alternating spray the same amount of fuel.

Joe Perez 02-17-2010 09:25 PM


Originally Posted by Chris Swearingen (Post 524102)
So 1 squirt simultaneous and 2 squirts alternating spray the same amount of fuel.

Yes, give or take the accuracy of your lag figures.


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