Need scaling assistance/guidance/opinions please

[Batmanntexas]

First things first. I am a beginner, working on my own car. I am utilizing my current tune file, as my base file, to work from. My setup is as follows: 2012 Camaro SS, LS3; Whipple 2.9L w/3.75" pulley, stock harmonic balancer, LS9 camshaft, long tube headers, no cats, full 3" exhaust, 63lb injectors, stock engine internals.

I am getting ready to upgrade to 95lb injectors and a triple fuel pump setup. Aside from the increase in injector, everything else will remain the same. I am attaching two files. The one that I have attempted to scale, and my base tune file that the car is currently running on. I am asking for knowledgeable folks to look at the files, and let me know what I have missed. I really appreciate any help that you folks can offer.

I will also include the injector data that was supplied by the vendor. I scaled the tune at 80%, maybe I should scale the tune at 50%?

In any case, info is attached. Please let me know what you think. Thanks in advance!

-Scott

[Batmanntexas]

I should also add that I went through the High Octane/Low Octane spark tables, copying the 80% scaled values into the appropriate blocks (.20 into the .16, .40 into the .32, .60 into .48, etc.). I did this on the Max Torque Timing table as well. That is the correct way to scale those tables, yes? If so, do I interpolate the rest of the table?

[Batmanntexas]

Nobody has any input, ideas, comments, etc?

[MikeOD]

Why do you need to scale? The injector flowrate table on these newer cars mazes out at 127 lb/hr, and the Mass Air at 4000 g/sec...no need to scale with these injectors.

The reason you're thinking you need to is kinda flawed...the injector flowrate table covers a MASSIVE pressure delta range that realistically you can never ever see. Where these injectors finally max out the table...you'd never possibly get there.

When you're at atmospheric pressure, you'll be right around the 408 KPA cell, where your IFR is 115.4 lb/hr. When you're at say 10 pounds of boost, your IFR will be 103-106 lb/hr, and when you're in deep decelleration, closed throttle, high RPM, pulling a lot of vacuum, you'll be just about at 126 lb/hr for your injector flowrate...anything further to the right of the table where the IFR gets higher, you'd probably never ever see.

That said, if you still want to scale things just to be certain you're covered...you can just cut the IFR in half, and double stoich in the stoich AFR table.

[TunedByNishan]

You don't need to scale this tune.

This PCM has a maximum allowable value to be entered of 127 lb/hr for Injector Flow Rate which should cover your entire operating range.

[mowton]

Why do you need to scale? The injector flowrate table on these newer cars mazes out at 127 lb/hr, and the Mass Air at 4000 g/sec...no need to scale with these injectors.

The reason you're thinking you need to is kinda flawed...the injector flowrate table covers a MASSIVE pressure delta range that realistically you can never ever see. Where these injectors finally max out the table...you'd never possibly get there.

When you're at atmospheric pressure, you'll be right around the 408 KPA cell, where your IFR is 115.4 lb/hr. When you're at say 10 pounds of boost, your IFR will be 103-106 lb/hr, and when you're in deep decelleration, closed throttle, high RPM, pulling a lot of vacuum, you'll be just about at 126 lb/hr for your injector flowrate...anything further to the right of the table where the IFR gets higher, you'd probably never ever see.

That said, if you still want to scale things just to be certain you're covered...you can just cut the IFR in half, and double stoich in the stoich AFR table.

Mike is absolutely correct. If and when you need to scale, only take the scaling process to 480/488 kPa (this will be where you want to attain your hard-coded limit). You can calculate your scaling value by dividing the hard-coded limit by the rated IFR at 480/488 kpa.

Ed M

[tramotorsports]

I understand cutting IFR's in half and doubling stoich values for fueling limit. but, in order to get past maxing out the 1.36 g/cyl hard code, wouldn't proper scaling of the tune be necessary?

[mowton]

Actually the Half/Double will not prevent you from maxing out the g/cyl limit, only scaling can do that. The Half/Double is only used to fit the injection flow rate value within the hardcoded limit. Nothing changes other than the fact you tell the PCM the Injectors are half the size but you tell it also that the mixture requires twice the fuel. Together this gets you back to even if you will. No air models are effected so scaling isn't required.

AFR = Mass of Air/Mass of Fuel

Ed M

[tramotorsports]

Sorry for my ignorance, but if you've got a need for that much injector; aren't you likely going to be maxing out the airflow limits?

[mowton]

Sorry for my ignorance, but if you've got a need for that much injector; aren't you likely going to be maxing out the airflow limits?

His Air Flow max is 4000 g/sec so he won't hit that. Can increase charge pipe diameter to get back some MAF Hz resolution if the MAF runs out. The other reason for larger injectors like that ould also be to support an E85 conversion, where you wouldnt exceed even say the lower 512 g/sec limit.

Ed M

[tramotorsports]

His Air Flow max is 4000 g/sec so he won't hit that. Can increase charge pipe diameter to get back some MAF Hz resolution if the MAF runs out. The other reason for larger injectors like that ould also be to support an E85 conversion, where you wouldnt exceed even say the lower 512 g/sec limit.

Ed M

Good call on lower stoic point fuels. I guess I worded that wrong. I meant airmass limits, such as the 1.36 g/cyl on the spark tables...

[mowton]

Good call on lower stoic point fuels. I guess I worded that wrong. I meant airmass limits, such as the 1.36 g/cyl on the spark tables...

IMHO. yes, he could and probably will hit the 1.36 limit. It comes down to a trade off between maxing at the 1.36 g/cyl value and setting this timing row to the lowest possible timing required, versus a complicated and time consuming scaling effort. This is especially a consideration in an automatic setup where the scaling throws off the Torque Model and you need to adjust the Torque Coefficient tables Airmass A-D to realign the torque model. Its six of one and a half dozen of the other. With his setup (2.9L Whipple/3.75 pulley, he will probably see about 13-15lbs of boost based on the LT headers/no cats influences.

Ed M

[MikeOD]

Good call on lower stoic point fuels. I guess I worded that wrong. I meant airmass limits, such as the 1.36 g/cyl on the spark tables...

You can change the axis on the spark advance table in these PCM's as well...keep the resolution where you need it, and then make sure you cover the airmass you need to everywhere else.