fi_junky

So from what I've read, my 97 5.4 has 21# injectors. I found a good deal on some Ford Racing 24# injectors and was wondering if replacing the stockers with no tune on a pretty well stock truck would hurt or help. Thanks in advance!

kaboom10

The MAF calibration, slopes and break point are set for the 21# injectors. All these would have to be retuned for the 24# injectors. U could get a tuner made by SCT and have a dealer make u a tune if u really want to use them. The 24# will also function without a retune but u might experience lower gas mileage and/or driveability issues. U would be further ahead by swapping your NP heads for NPI heads and related intake system.

fi_junky

So, my question is, let's say i do a retune with the sct what type of power gains can i expect with the gotts mod, silencer removal, k&n filter, & cat-back exhaust (with stock cats)? Will the injectors be able to supply a tad bit more fuel at a lower percent duty cycle in turn making things a bit more efficient? Thanks

kaboom10

With all of those mods there will not be any reason to add any extra fuel, although the O2 bias can be tweaked, at any point. Added timing in the tune and using higher octane gas will give u quite an increase.