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Uncommon strategy regarding staged injection and what has worked well for me
Regarding the topic of staged injection, the strategy I use differs from anyone else. I figured I might as well share my findings as this has worked best for me.
My injector setup is 'square' - four ID1050x and with 80 lb base pressure it makes them flow roughly 1400cc
The problem I see many setups is having the stage gradual. At the beginning of the stage event the pulse-width can be too small to control accurately and this can cause stumbling and jerkiness. To get around this, many simply make the transition very steep - starting out at say 30-50% - to quickly sweep past this small pulse width zone at the beginning of the ramp. At the end of the day this unstable state can still exists and is just minimized. I have found that method to be unnecessary.
If you look closely, you can see from my staging table, I have 2 columns and 2 rows labeled the exact same value. Odd right? What this does is allow for a on/off trigger effect on the secondary injectors. When the secondaries switch on, they jump straight to a more stable pulse-width. This bypasses the 'ramping' transition of a gradual onset. In addition to this, As you can see, my table is much more simplified than most. I simply switch them on right before I get into boost regardless of rpm... (aside from below 1000rpm.. I was getting unwanted triggering of the secondaries while cranking.)
Well, this has worked for me and I feel absolutely no hesitation this way even when flirting with the 98kpa threshold triggering on and off the secondaries . My fuel map looks more for lack of a better term.. smooth. It has minimized strange valleys and peaks which may have been the cause of a more complex staging table that ramps injectors in at varying pressures and RPM. Give this a try if you will.. or don't. I'm simply sharing the knowledge which is what this forum is created for!
What you're experiencing when bringing them on at extremely low duty cycle is the lower non-linear operating range of the injectors at which the output is unstable. Injector dynamics has actually done the work to characterize this range for each of their injectors and posted a pretty solid write up on how it works, see link below.
When possible, I feel it is beneficial to circumvent this non linear area all together. The only time I am ever below 1.5ms is at idle and possibly cruise.. where this injector data is most beneficial
this sounds exactly like what I need. when my secondaries are just beginning to stage, it's PIG rich, and I haven't been able to ever tune it out fully.
i'm so excited to try this out tonight. thank you!
this sounds exactly like what I need. when my secondaries are just beginning to stage, it's PIG rich, and I haven't been able to ever tune it out fully.
i'm so excited to try this out tonight. thank you!
What ECU? If its going stupid rich it likey isn't the nonlinear low pulsewidth range, but there are workarounds on about every platform now.
06-05-19, 09:55 AM
