Firmware suggestion

[tastyratz]

I wanted to make a suggestion.
Currently the ems processes boost compensation/accel and possibly other fuel trims AFTER calculating injector phasing. Is there any technical limitation the EMS processes these in this order, and could changing this appropriately be done through firmware? While boost comp could be corrected for it is an extra correction step on the user end when tuning your maps.

I also think injector phasing calculation could be implemented in a wizard to generate more appropriate phase basemaps seamlessly.

[SB]

Thanks but I'm not sure I understand the goal of what you're asking.

Currently the injector phasing defines the beginning of the injection pulse, and the end of the injection pulse will depend on the length of the pulse. No matter what the fuel trims are (including Boost Fuel Trim), you are always able to define the tooth (crank angle) at which the injector opens as opposed to when it closes.

I realize this is different than some other standalones but it is quite a bit simpler from a firmware standpoint. If you have info showing that defining the end of the injection pulse is better I'd personally be interested in seeing it and perhaps that could eventually lead to a firmware change.

I do agree that forcing tuners to think in teeth may not be the best way to display the ignition and injector phase info. This is something that could pretty easily be updated in future versions of AEMTuner.

[tastyratz]

I suppose my original post wasn't really worded well.

My thought on it:
By setting the start of the injector phasing you are able to identify the ideal injection point, but it requires a lot more finagling and referencing for the ideal injector stop time. You don't want to be spraying fuel on the back of a recently closed intake valve as it is about the worst timing possible. This can easily be done inadvertently with trims (actually probably more so with accel pumps if anything)


While it may just be simpler from a programming perspective to define a start point, Perhaps a better way from a functional perspective would be the ability to set the ideal injection point (phasing) as well as latest injector stop time? This way you would spray fuel at the ideal injection point you defined every time unless the injection stop time would exceed x degrees/teeth. For example, If the injector requires 5ms, but only has 3ms before reaching the predefined stoptime - the injector will begin spraying 2ms earlier to compensate. Simple yet effective.

Maybe we can have our cake and eat it too

As far as what I meant by a wizard:
Something similar to the excel spreadsheets floating out there to calculate ideal injection time by theory. You could punch in your intake valve closing point (this would be redundant and un-necessary if the previously mentioned setting were implemented) and you could enter your exhaust valve closing point in degrees (ideal injection point). AEMtuner would then generate a phase map based on that criteria of which you could then tweak and fine tune to your needs. This would make injector phase tuning a little more accessible to some people and hopefully save others on dyno time by getting them closer before they start (Who doesn't like saving money and time=money).


I also agree, forcing the tuner to think in teeth is mind boggling sometimes. I personally would love to see it translated as a scaler to crank degrees under program options. Sometimes it feels equivalent to having to think in psi when you want kpa, and vise versa.

[Mello]

My thoughts are - the best time to inject fuel is when the port velocity is the highest; which wouldn't be at exhaust valve close time.  I really only noticed that injector phasing makes any difference at all is while at idle and cruising when the engine isn't really under any load.

[tastyratz]

Yes, that location isn't exactly the same for all engines/setups/cams/etc... but the idea in the wizard was just an example to get you close. If you decide it should be 5 degrees sooner/later you just enter a different start point number in the wizard...
exhaust valve close is near ideal - some engines might want a little overlap, some have minimal and would draw too much fuel out the exhaust.

None of this can replace tuning because every engine is different and it will need to be tweaked on the dyno/street... but calculation makes for better basemaps.


I also wanted to add onto this - I started thinking last night. 2 The latest injector stop point settings would be ideal for staged flow setups so the earlier injectors can be timed appropriately as well. (I dont run staged flow, but it's worth a thought for the people who do)

[T78HT]

In my V1 1.19 tuned map Injector Phase is 0.00 teeth and the newest 6speed base maps for the V2 have a Injector Phase of 17.625 teeth. Would this cause my car to run really rich??

What would happen if I changed the 17.625 to 0.00??