30# injectors? too big?

I have my OEM 19# injectors that are in fine condition if you want to make me an offer. Do you need an OEM fuel rail or K&N FIPK 2? Lol, I still have lots of my original stuff in my garage since I put my blower on. Btw, I run 24# with my 1.7L blower but I don't know what HP I'm making.

3 years? lol...

i would just get on the millions of mustang websites and hunt someone down who is upgrading and to snag up their old stuff.

nmcgrawj said:

3 years? lol...

i would just get on the millions of mustang websites and hunt someone down who is upgrading and to snag up their old stuff.

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Agreed with above. Or a junkyard and pull them, they'd probly charge you around 5 bucks per injector.

Adam

ronstang94 said:

I thought that as long as you have a MAF calibrated to the correct size injector then you dont need a tune?

It will probably be atleast three more years until I can do everything that I want to on the car, when I finally finish school. or sooner if the engine blows up

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I've heard two different explainations on bigger injectors...

I've heard even if you have the correct MAF the engine will still run rich.

On the other hand, I've heard that as long as the MAF matches the injectors it should still use the required amount of fuel.

I've just seen people put larger injectors and matching MAF on their stock engines and have it run REALLY rich and have idle issues etc.

If you want to give it a shot then go for it. But I'm just saying if it were me I'd just find some cheap 19# injectors and use them for now.

Like most things I guess

Application has a lot to do with an answer that takes into consideration
the different ways one could give helpful info here

Having said that ... I would answer first with ... It depends

Two things to consider when talking about size of injectors

1 Formula details
2 Fuel pressure

1) Those formulas you find all over the net to determine inj size use
fwhp NOT rwhp

2) You are gonna use one or the other to control the injectors

a mechanical means (afpr)
b custom tune

a) If using elevated pressures the inj will act as if it is bigger
b) using a custom tune is usually done with OEM pressure
therefore that needs to be taken into account

I like to do it like Ford does it

OEM pressure
Inj size with a bit of breathing room
Make adjustments as needed in the pcm

I agree with the above peeps

19's and OEM meter will work dandy
24's and caled meter will work pretty good
30's and caled meter will most likely idle and cruise a bit fat
and
Cold starts will be done with REALLY fat mixtures
but
You most likely can drive it
also
Your pcm load factors are gonna be all outta whack
but
We won't go into that here

36's and larger will not work so good with no tune

Summing up

At OEM fuel pressure 24's are close to the limit for most street combos
at the high 200's to 300 hp to the wheels

Remember ... stick trans combos with 350 motor is only 297 wheel

Just a bit more info to think about

Grady

I really wouldn't go bigger than 24s without a tuner and willingness to have idle and starting issues. Turning up the pressure will help with atomizing the fuel, but without a tuner, it will still have issues and will run rich in open-loop (i.e. when it's cold and at wide open throttle). The way I see it is once you have done enough to the motor where you NEED a tuner, you will have maxed out the 19# injectors anyway. So until then, don't bother.

Zero Signal said:

I really wouldn't go bigger than 24s without a tuner and willingness to have idle and starting issues. Turning up the pressure will help with atomizing the fuel, but without a tuner, it will still have issues and will run rich in open-loop (i.e. when it's cold and at wide open throttle). The way I see it is once you have done enough to the motor where you NEED a tuner, you will have maxed out the 19# injectors anyway. So until then, don't bother.

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+1 over 24's need some type chip.

Zero Signal said:

I really wouldn't go bigger than 24s without a tuner and willingness to have idle and starting issues. Turning up the pressure will help with atomizing the fuel, but without a tuner, it will still have issues and will run rich in open-loop (i.e. when it's cold and at wide open throttle). The way I see it is once you have done enough to the motor where you NEED a tuner, you will have maxed out the 19# injectors anyway. So until then, don't bother.

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What John said

Sticking to the 94-95 pcm's

They are load based where the Fox body pcm's are rpm based

Having said that ... The pcm determines load from the meter's output

When you move away from OEM 19's & meter and use the aftermarket
meter's cheat method (running a larger set of inj's and meter with no
pcm adjustment) of matching meter to inj size the load reported to
the pcm starts to become skewed

With 24's it is not too bad
but
As you move to 30's the error grows larger
and
With 36's and 42's ... it is WAY OFF

So you see ... there is a WHOLE LOT more going on here than most
are even aware of in this situation

It is most important to understand this fact :Word:

That whole aftermarket meter cheat method was developed for the
Fox Body Stangs and their RPM BASED pcm's

So you see ... you are using a method not designed for our 2 year run
of pcm's found in our cars here

anyway ............

For a mild combo at say mid 200 rwhp levels ..........
You can run 19's at elevated fuel pressure

24's and a meter caled to match them run at elevated fuel levels have
supported 300 rwhp or a bit better but those inj's are being worked for all
they got to give ... and in some cases ... beyond

Finally ... Like John said

When you start modding you will run out of inj (OEM 19's) pretty quick
You always reach fuel limit before meter limit .........

One of those things where you can prick your finger
and
Write it on a white sheet rock wall

As a matter of fact ... the OEM meter will take you to around the 300 rwhp
mark if you have pcm access

Summing up ... you can somewhat tune a 94-95 with dizzy twisting and
playing around with fuel pressure

BUT

There is only so much you can expect from that method

So Ron ... have we caused you to think about anything

Grady