FIC's 142lb. Is Doubling Stoich and halving IFR the wrong way to scale?

[TCSS07]

are you still going above 1.36 airmass? if so then thats why you need to scale the tune but if you arent then don't worry about it and continue on

[justhereforinfo]

Yes. I will be going up to 2.25 probably. I am currently passing the 1.36 limit now.

Can you help me to understand the difference between maxing the spark table on a 90# injector and maxing the spark table on a 142# injector?

[TCSS07]

There isnt really a difference between maxing the spark airmass limit with either the 90# or 142# injectors if either one goes over the max limit. You need to scale the injector flow rate to make the ecm think the injectors are bigger than they actually are which in turn will lower the cylinder airmass and bring you back down so you regain spark control but as to how much you'll need to scale will depend on your max you hit. So let's say you hit 2.5 g/s cyl air. if you cut your flow rate in half then your max would probably be around 1.25 g/s cyl air. Dont quote me on the % scale accuracy you will need I was just saying as an example so you kind of get a idea. Raising the flow rate will make the cyl air higher and lowering the flow rate will make the cyl air lower

[07GTS]

have u tried to click on the axis and see if u can change it ? its only the early e38 that u cant since i havnt seen your tune file im not sure but about late 2008 up should be adjustable airmass axis

[jjs]

Great information

[TCSS07]

07gts - yeah, youre correct. i forgot about that im use to the old gen ecus that dont have that ability.

justhereforinfo - you can do that open the spark chart and go on the left where it says spark airmass and you change change some of the upper end values to accommodate for the higher cylinder airmass but youre still going to loose resolution to a point because you will have to sacrifice some of the other cells but it can be done factory goes up by .04 for the airmass if you had it go up by .06 or .07 every row that would help you out if you didnt want to scale the fuel flow rate. i opened your tune and multiplied the spark airmass by 1.7 and it made the first cell .014 and the top cell 2.31 where its a .07 difference between cells vs factory of .04. that would probably work for you so save it as a different file because you will have to copy over the spark to the proper cylinder air mass rows since the scaling is all different now. what was .60 air mass stock is now 1.02 cylinder airmass and it will also through off the other spark sub charts like idle,ect,iat as well so keep that in mind

[justhereforinfo]

Very cool. I didn't know you could change the increments on which the axis increase. I appreciate the advice on spark tuning, but I think you may be jumping ahead of my current problem. I'm still trying to get the injector data input correctly.

If I just drop the injector data in as is, the fuel trims pull a few % out and it drives ok out of boost. But as soon as I get into PE, its a disaster. I have an Auxiliary pump that kicks in when it sees boost, and goes very rich. It runs well enough to get it to my tuner.
FIC Data not scaled.PNG
FIC142noscaleDrive.hpl

I was just hoping that I could install these larger injectors and use the "Double stoich, cut IFR in half (and ivt terms)" and be done. No additional tuning. It seems that's not the case.

I will let my tuner figure it out.

[justhereforinfo]

So the tuner doubled stoich, halved IFR, drove it, copy and pasted afr err into maf a couple of times and done.

EDIT: I wanted to add that in order to start the car when hot, I had to ADD 10-20% to the Cranking Fuel table between 158-212 degrees.

[Ben Charles]

Yep!!!