Guidance on injector tuning for a 2015 Hellcat.

[fumanchu182]

This is a cross thread from HP Tuners forum but not everyone is over there so if anyone has any advice it would be appreciated.

=====
Total noob here but trying to learn. I want to add larger injectors for future plans: pulley and boost a pump. I am ordering ID-1050-XDS (1050.48.14.14.8) and plan to install them myself (easy day) and do fueling for P/T on the street and then WOT testing on a dyno (the hard part). To begin tackling this task I pulled down the injector data from their website (http://help.injectordynamics.com/helpdesk/attachments/4042718026). After looking at the data I went and loaded a read of the current tune in the PCM and adjusted the following tables:

[ECM] 34050 - Injector Pulse Width vs. Fuel Mass
[ECM] 34052 - Fuel Mass vs. Injector Pulse Width
[ECM] 44436 - Startup Injector Pulse Wdith Scalar
[ECM] 44439 - Inj PW Min
[ECM] 34070 - Injector Pulsewidth Offset
[ECM] 34086 - Fuel Mass Mult vs. Fuel Temp

I noticed that while inserting the data into the UI I could not get exact values to be placed into cells. I placed a ticket in with support as I thought this was a bug and they explained that there are only certain values that can be placed in fields that the original programmer of the PCM/TUNE will allow. I thought this peculiar because what is the difference between 2000.00 and 2004.00. Apparently Binary Coded Decimals on smaller memory footprint systems is a thing, but I'm challenging this assumption so lets see where that goes. I digress. So I tried my best to make sure that the values lined up closely but I learned there is a lot of interpolation that happens on the backend in VCM editor on its own. Don't know if I am a fan of this but I guess I can get used to it as long as I get the results I want and nothing turns into a grenade.

I've attached a screen shot of what I am talking about


How I scaled the Inj. Pw. vs. Fuel Mass and the inverse table is another story. I noticed that in the stock tune the line is linear so I thougth that if I could get my new data to match that line via linear interpolation I'd be in a good spot to start off with till the pulley comes in. In the same spreadsheet from ID I made a new table and added a linear intepolation function using (0,0) and (443.741, 30000) as the known lines on a 2D graph. From there applied standard linear interpolation and came up with the following values:


I did a comparison of the graphs and they both look very linear and the slope is almost the same.


Attached is the tune as well.

So I have the following questions:
1.) Am I doing this right or is there another method that I'm not aware of?
2.) Did I miss anything that anyone would like to share?

The math makes sense in my head because the ID 1050 injectors are on a ratio of 10:21 bigger than stock so I'm okay with the values I created. What I can't get over is that I can't type in exact values into the UI. Is anyone else experiencing this? Is this by design or have I once again found a fringe test case.
=====

Any advice would be appreciated. I'm new to this but you don't need to be gentle, if I'm fucking this up bad, let me know.

 

[BULL]

Subscribed

 

[fumanchu182]

Injectors are in. Tune has been written. Somehow I drained the battery by giving her a few start cycles trying to depressurize the fuel system.



I didn’t voluntarily take the cowl and brace off. Fucking injector clip left with the fury of a thousand fuckheads and fell to the back of the motor. Got to play a bonus round of find the fucking fuel injector clip. All is well though. Wrote a starting tune, uploaded now just waiting for battery to juice up.

 

[fumanchu182]

 

[fumanchu182]

So there is really not much to it for putting in injectors and scaling them. The hardest part was finding a stretch of road where I could do the second gear from 2000-4000 to simulate most traffic. The data from ID is pretty spot on and I only had to adjust for a little bit. As you can see in my log attached the LTFT barely moved after one revision. I did a wot pull but don't want to use the data as it is not a track pull. I plan on doing a track/test-n-tune so I can get WOT data and adjust accordingly.

If anyone would like me to go over with what data I updated Injector Pulse Width vs. Fuel Mass I will gladly do so. For a stock hellcat it is pretty much plug and play. To get idle down you do have to disable some things, let the car idle for two to three minutes and then you are good to go.

 

[Speedy!]

Good info, glad to see others getting in to their cars.

 

[fumanchu182]

Good info, glad to see others getting in to their cars.

Thanks brother, easy day really once you just take a breath step back and realize that you can't break it unless you do something really really stupid. A 2.72 pulley is on the way but before that I got a BAP to install, just waiting on the boost adapter to come in.