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question about swapping inj.s and tune

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Old Apr 6, 2007 | 11:49 AM
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Irocss85's Avatar
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Default question about swapping inj.s and tune

just got a dyno tune, was told stock inj.s are fine still. put down 417 RWHP on a mustang dyno on a home port/cam package. AFR is tuned good (scale shows hoovering around 12.5 and dips just below near the end of the pull)

question is, if I install bigger inj.s that I already have (got a good deal on some low mileage SVO red tops) is it easy to change the tune to reflect the inj.s size? or would it require the wide band and more tuning due to the change? not sure if there's just a setting that gets changed and the computer makes all the required changes, or does it require goin through the maps again?

TIA

chris
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Old Apr 6, 2007 | 11:53 AM
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very easy to change the IFR table for new injectors. There is a IFR calculator in the sticky here that will do the trick for you.
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Old Apr 6, 2007 | 12:06 PM
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that was quick. thanks. gotta go out and drive the car this weekend, and take a snap shot of the "pass". when I did that real quick it showed 17ms inj. pw but I didnt pay attention to the rpm. I found the scale for figureing duty cycle, and at 5500and above 17ms is 80+ % which Im not happy with at all. I'll do another run this weekend and if its at that ms at the high rpms, I'll swap out the inj.s and have him update the tune if all he's gotta do it plug in, change a parameter, then download.

the tune is awesome, Im just worried and don want to risk goin lean, EVER. and since I already have the other inj.s so its not like I need to pay $350 for them. AND, were installing a custom speed inc. fuel rail/stainless braided lines anyways. so its no exta work at all.

what do you think? swap them out, or maybe ok still at my HP level? my tuner says I'll be fine. Id just rather eerr on the side of caution instead of trying to save $100. not doin any power mods for a long time. time to work on the susp. and track times. so I wont be upping the power for atleast a couple years from where its currently at.

I should also add this car only has 6K miles on it, so there not worn or dirty.
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Old Apr 6, 2007 | 12:08 PM
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I would swp them, rescale the IFR table to match, then reflash the PCM. My 42lbers flow 84% more than the stockers so i just multiplied the entire IFR table by 184%. Pretty easy to do.
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