Translating Fuel Injector Data

[hugemikeyd]

I have purchased 1000cc injectors from https://fuelinjectorconnection.com/ and I would like to make sure that I have properly configured my injectors based on the attached spreadsheet. The data for ECU Link seems to be spread out across multiple tabs so I just want to double check that i put it all in correctly.

Appreciate the help!

1000cc(6117)48mmev14_03242022.xlsx

[koracing]

Injector flow @ Rated Pressure: 1041.6 cc/min = 99.2lb/hr * 10.5(cc/min)/(lb/hr)

G4x Injector dead time table attached based on my own testing and tuning with their 1000cc injectors on Link G4x and G4+ ecus.

Injector Dead Time FIC 1000cc.lte

[hugemikeyd]

thanks! i am curious how you worked out the dead time table? i can't find anything close from the data they sent me...

[hugemikeyd]

i put in your adjustments and the car runs WAY better, super appreciate it!

[koracing]

Dead time has the largest affect at idle or in other areas of the map where the effective pulse width or duty cycle is very low as the dead time in these cases will often be much higher than the calculated effective pulse width.  Actual pulse width commanded to the injector is the addition of injector response time aka dead time and calculated effective pulse width.

Usually provided data is not 100% correct unless it was set up with the same ecu (so it has the same driver hardware).  It is very critical also to make sure you have the correct engine displacement data, and injector flow value entered.  You also need to be sure you're setting the dead time for the differential fuel pressure the engine is operating at. 

If you're unsure if your deadtime is correct, and if you want to check it - do the following after warming up the engine fully and having no more warm up enrichment active (or any other active fuel trims ideally):

1. tune idle to run right on lambda target with closed loop off or as close as you can. (for example 1.000 lambda)

2. Change lambda target to 0.9 lambda and see what value the afr goes to.  If dead time is correct - the new lambda value will match target.

At this point if it is not hitting the new target the dead time needs to be corrected.  The following is what I do, and may not be the best way, but has worked well for me:

A. If when changing from 1.0 lambda to 0.9 lambda target the AFR undershoots - does not go all the way down to 0.9 - you have too much dead time and not enough resolution on the VE table.  Reduce dead time and retune the VE table to match target.

B. If when changing from 1.0 lambda to 0.9 lambda target the AFR overshoots - goes past or below 0.9 - you have too little dead time and too much contribution from the VE table.  Increase dead time and retune the VE table to match target.  

Rinse and repeat.

Ideally you will do this at multiple voltages to generate a correct curve, but being able to apply multiple voltages to a car's injectors, ecu, and ignition while it's running isn't something everyone has the ability to do, and in the real world you're usually going to be operating at roughly the same voltage plus or minus a volt 99% of the time, so it's certainly critical at a minimum to get the dead time right at nominal operating voltage.  If you have an adjustable regulator you can also perform this same test at multiple differential pressures to get a good 3D dead time table, it just takes time.

 

Having correct dead time makes all the tuning go quicker afterwards as all changes that are predicted to be needed based on AFR readings will be more accuately applied, as well as all fuel calculations and corrections the ecu is using will be applied to the actual effective injection pulse.