How does changing injectors/data effect fuel tuning?

[epfatboy]

So I have a tune from a cammed 6.0, building a replica combo ( accept I "need" to use a LS1 style FAST 92mm intake vs a truck intake, yes I know but wanted to hear about fuel first) and I'm planning to use some DW 42# instead of FIC 540cc.

So assuming the only change I made was the injectors and the associated data changes in HPT how far off would the VE be? I know there are other factors so its never perfect but theoretically shouldn't it be very close?

And while I'm at it yes the intake is being swapped, the MAF/TB remains a stock GM 85mm/78mm on both so that should limit the change there but I know it's going to have an effect. The cam in each is a Summit stage 2 street .625/.625 226/238 113, both have 11:1 compression. Combined with the above injector change how far off are we talking?

Also, this is a fresh build. My assumption is it's gonna fire and idle no problem as the configs are pretty close, good assumption or should I make a few changes, I already planned to up the Idle RPM.

Thanks for any help.

[blindsquirrel]

If the old injector data was perfect and the new injector data is also perfect, then there will be zero zip none nada changes to MAF/VE. The PCM just does math to figure out how long to turn on the injector, it has to know how big the injector is to calculate how much fuel will come out when it's pulsed for X amount of time.

Even if you used exact identical parts for everything it would still need its own tune, you're worrying about the wrong things here.

[epfatboy]

Thanks BS, that helps validate whats going on.

I tried Holley and decided to use OEM/HPT for this build. I'm looking forward to using OEM/HPT again and not afraid of digging into some tuning. Just wanted to understand what I was in for and to ensure I was thinking about startup correctly.

My next blindspot will be nitrous control, I liked the idea of Holley's built-ins and running a dry setup, if I have to go wet cause it's OEM/HPT I'll probably port the intake versus use a plate, I don't like the idea of fuel in a place designed to support air flow.

.

[Alvin]

I personally like OEM controllers better for driven swaps. Driveablity especially as seasons change seem way better.

Just no nitrous control, WOT fuel trimming.

[epfatboy]

The Holley wasn?t bad for drivability but it?s not the OEM in terms of addressing just about any condition.

What brought me back was:
Durability and Warranty, If the Holley PCM goes your out $1000 after 1 year. And the OEM stuff just doesn?t break anyway but if it does your $100 max. I lost my WB heater circuit on my Holley, I hear it happens and Holley told me I was out of luck after just 3-4 months of actual use.

But I was probably coming back anyway, just wanted to try something new for a bit, now I know?

[Alvin]

What people think is driveablity can vary.. In the same week I can have

Customer A "it runs good, just needs to have the tune finished up" when in reality its down a whole cylinder cause it wiped a cam lobe.

to

Customer B. My 239/244 duration cammed car with light weight clutch bucks at 1200 RPM.. <- 100% honest that happened last week.

[edcmat-l1]

^^^^ Truth

Had a customer drive here from 50+ miles away, 5th gen Camaro, newly installed cam, running on 4 cylinders. 4. Exactly half the engine. He just thought it needed tooned.