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Discussion Starter #1
Will there be any noticable difference (fuel economy, power, responsiveness etc) if I where to install 30# fuel injectors with a chip tunes for 30# over 19# with the same chip, except tuned for 19# injectors? I've been told that the 19# injectors are operating around 85% duty cycle in the Explorer 4.6's, and was wondering if the 30# injectors would yield better economy due to more precise metering from the lower duty cycle.
 

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Unless you have major mods you absolutely do not need bigger 'jectors! Blower/ Nitrous, Stroker, Rad cam/Heads, yup, otherwise you are wasting money , soon to be wasting gas .... think about it.... bigger injector equals more fuel, with a shorter pulse width(on/off time) meaning less metering accuracy... also unless you get the sprayer plate kind, you'll end up with pintle types that don't atomize as good, as the stock ford sprayer plate19# 'jectors... there will probably be a slight loss in economy, and you may get a tad stronger engine with an extremely good setup, but not too much.. ceartainly not worth the price of admission./.. get an adjustable fuel pressure reg. and press guage (any brand except BBK) and play with that instead to get things running on the money......Good Luck.... just 1 mans opinion....
 

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Discussion Starter #3 (Edited)
Wouldn't the chip compensate for the larger injector, and still deliver the proper amount of fuel?
 

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19# injectors with the fuel pressure set at 39.5 psi (without vacuum) will support a naturally aspirated engine to about 300 HP at the crank.


Check here:

http://www.modulardepot.com/?show=articlesdet&aid=21


and here:

http://www.modulardepot.com/fuelcalc.php


If you are not pulling that much HP at the crank, there is no need for larger injectors. You are throwing money away on injectors and the EEC flash you will need to run the car after you install them.

Bigger is not always better, unless you have the other mods to support it.
 

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Yup, the chip will compensate, but still, a little less economy, almost no xtra power, and tad tougher time metering down a bigger than necessary injector...when you are approaching over 300 hp , time to move up ,.... till then, you can do it, but why?In my personal experience, the 24 lbs were ok, but used more fuel, and my track times were not all that much better... I am running 42# 'jectors with 6 # boost right now, and even without getting into boost it burns plenty of fuel, go figure.....
 
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