19 Lbl injector Limits
09-11-2013, 06:57 AM
#21
6th Gear Member
Join Date: Mar 2010
Location: Wisconsin
Posts: 5,061
If you want a ride along vid, go to Youtube and type in "88 Mustang 1/4 mile
pass". I'd post a link, but for some reason they never work here.
Last edited by 88 orangepeel notch; 09-11-2013 at 07:05 AM.
09-11-2013, 08:39 PM
#22
3rd Gear Member
Thread Starter
Join Date: Sep 2011
Location: Florida
Posts: 632
@Pontisteve: Gee could you not be so vague!? lol Just kidding! Wow, thank you for that! So if I am understanding you correctly, I should be fine just putting on the 24lbl injectors, get the proper calibration tube for my C&L MAF, re-tune my Bama chip, and I should be fine right? My whole worry is I'm not sure what the actual hp will be once I put the intake on. I know the heads will limit everything I've done, but who knows until it's on a dyno. I just don't want it to run too rich or too lean.
@Orange Peel: Yeah I was thinking of going with the 3.55's I want shorter gears, but I don't think the 3.08's are too bad either. I mean, I like having the taller gears sometimes when I'm on the highway.
@Orange Peel: Yeah I was thinking of going with the 3.55's I want shorter gears, but I don't think the 3.08's are too bad either. I mean, I like having the taller gears sometimes when I'm on the highway.
09-12-2013, 03:07 AM
#24
Join Date: Apr 2010
Location: FL
Posts: 8
I'll try to be a little less vague next time. LOL
You need to understand there are two ways to make the computer work with a larger injector like your 24's.
#1 The right way is to have a chip programmed for the exact injector you are using.
#1 The band-aid way is to run a calibrated MAF. This method runs a skewed MAF reading, that under-reports airflow to the PCM, so the PCM will under-calculate fuel requirements, and send a lower pulsewidth to the injector. The injector is bigger than the computer knows about, so even though it's open for less time than it should be, it's passing more fuel than the computer thinks it is.
Calibrated MAFs are a 20 year old trick employed by the aftermarket back in the day, long before EFI calibration software was available in the aftermarket. Once companies like SCT came along and gave us real software, we are now able to correctly program the tune for whatever injectors you use.
But calibrated MAFs are still around, and to this day are still being sold as a solution to larger injectors. It's just that they don't work very well, and the larger the injector, the larger your drivability problems are going to be.
You do one or the other, but not both. OR, if you want to run that larger "calibrated" MAF, and still properly program for the injectors the factory way, you can do that. You just have to program the PCM for both the MAF and the injector changes. You see, in the computer, those are two totally separate tables/sensors that have nothing to do with eachother.
I could program a stock computer for 60# Siemens Deka injectors, run a stock MAF and the 60's, and the car would run like it was bone stock. Or I could program for say a 30# calibrated MAF and stock 19# injectors, put those parts on the car, and it would run like it was bone stock. Only the aftermarket ties MAFs and injector size together, not Ford.
Off topic, a stock fox body MAF is a physical restriction, but electronically it flows about 350 HP worth of air before it pegs 5 volts. Unfortunately, the computer is programmed to fail the MAF at about 4.76 volts, or roughly 300 flywheel HP. A C&L MAF calibrated for 19# injectors is going to have enough electronic range to support about 450 HP, and enough airflow potential to as well. Even though it would take 30# injectors pegged out to make that same 450HP.
Running a C&L 19# calibrated MAF on a hot street motor with 24 or 30# injectors and a custom chip is a pretty hot ticket. Because C&L reuses the stock Ford sensor in their aftermarket cast aluminum housing that's CNC machined, the cost of that MAF is pretty low, the consistency is near perfect thanks to CNC, the range is more than adequate for all but the hottest street motors, and when I make a custom chip that calibrates the computer for that MAF and a set of Ford Racing injectors, the computer is happy and the car runs and drives great... from 19# injectors on up to 60#'s.
You need to understand there are two ways to make the computer work with a larger injector like your 24's.
#1 The right way is to have a chip programmed for the exact injector you are using.
#1 The band-aid way is to run a calibrated MAF. This method runs a skewed MAF reading, that under-reports airflow to the PCM, so the PCM will under-calculate fuel requirements, and send a lower pulsewidth to the injector. The injector is bigger than the computer knows about, so even though it's open for less time than it should be, it's passing more fuel than the computer thinks it is.
Calibrated MAFs are a 20 year old trick employed by the aftermarket back in the day, long before EFI calibration software was available in the aftermarket. Once companies like SCT came along and gave us real software, we are now able to correctly program the tune for whatever injectors you use.
But calibrated MAFs are still around, and to this day are still being sold as a solution to larger injectors. It's just that they don't work very well, and the larger the injector, the larger your drivability problems are going to be.
You do one or the other, but not both. OR, if you want to run that larger "calibrated" MAF, and still properly program for the injectors the factory way, you can do that. You just have to program the PCM for both the MAF and the injector changes. You see, in the computer, those are two totally separate tables/sensors that have nothing to do with eachother.
I could program a stock computer for 60# Siemens Deka injectors, run a stock MAF and the 60's, and the car would run like it was bone stock. Or I could program for say a 30# calibrated MAF and stock 19# injectors, put those parts on the car, and it would run like it was bone stock. Only the aftermarket ties MAFs and injector size together, not Ford.
Off topic, a stock fox body MAF is a physical restriction, but electronically it flows about 350 HP worth of air before it pegs 5 volts. Unfortunately, the computer is programmed to fail the MAF at about 4.76 volts, or roughly 300 flywheel HP. A C&L MAF calibrated for 19# injectors is going to have enough electronic range to support about 450 HP, and enough airflow potential to as well. Even though it would take 30# injectors pegged out to make that same 450HP.
Running a C&L 19# calibrated MAF on a hot street motor with 24 or 30# injectors and a custom chip is a pretty hot ticket. Because C&L reuses the stock Ford sensor in their aftermarket cast aluminum housing that's CNC machined, the cost of that MAF is pretty low, the consistency is near perfect thanks to CNC, the range is more than adequate for all but the hottest street motors, and when I make a custom chip that calibrates the computer for that MAF and a set of Ford Racing injectors, the computer is happy and the car runs and drives great... from 19# injectors on up to 60#'s.
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