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bigger injectors worth it???

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Old 03-17-2012, 09:59 AM
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DTMR
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Default bigger injectors worth it???

OKay so I have been hearing mixed things. I have the FRPP cams and i'm ordering the FRPP intake manifold and frpp throttle body soon. I also have a steeda carbon fiber intake and a full exhaust. Some people tell me I am gonna need bigger injectors, some say the stock ones will be fine. What will give me more performance?? Also what about fuel rails?
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Old 03-17-2012, 01:40 PM
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TheDutchTexan
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I doubt it, you are not going to dump that much more fuel in the engine.
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Old 03-17-2012, 09:27 PM
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I did a ton of research for my own build. Ford put 31lb injector's in the coyote 5.0. If you don't stroke your motor you will be fine. Ignore the injector's in my signature...I'm an experiment in progress
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Old 03-17-2012, 09:38 PM
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Originally Posted by Weather Man
I did a ton of research for my own build. Ford put 31lb injector's in the coyote 5.0. If you don't stroke your motor you will be fine. Ignore the injector's in my signature...I'm an experiment in progress
cool let me know how it turns out
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Old 10-16-2012, 07:38 PM
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Originally Posted by DTMR
cool let me know how it turns out
Sorry for the tardy post. One of the 60lb D-werks injector's failed right off the bat. Luckily, caught it before it hydrolocked my motor. Ended up using 39lb Ford Racing injector's he had in stock. Car runs great N/A with these.
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Old 10-16-2012, 11:25 PM
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Simon1
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Leave your injectors alone until a tuner tells you the motor needs bigger ones. Do not buy a throttle body spacer. It's snake oil.
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Old 10-16-2012, 11:52 PM
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siggyfreud
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Originally Posted by DTMR
OKay so I have been hearing mixed things. I have the FRPP cams and i'm ordering the FRPP intake manifold and frpp throttle body soon. I also have a steeda carbon fiber intake and a full exhaust. Some people tell me I am gonna need bigger injectors, some say the stock ones will be fine. What will give me more performance?? Also what about fuel rails?
The amount of fuel you need is dictated by the amount of air the engine can bring in. Simply adding more fuel isn't going to give you more power, unless, for example, you're running lean enough that you're being robbed of power. If you do some datalogging via your tuner, or on a dyno, you'll be able to see what your injectors' duty cycle is at. Duty cycles range from 0%-100%. 0% means the injector is open 0% of the time. 100% means the injector is firing all the time to keep up with the fuel needed. In my experience, I haven't looked to bigger injectors until my duty cycle began peaking above 80%.

All the injectors are is a spout. You can control fuel two ways. The amount it flows, and how long it's open. So if you can't keep the injector open longer to flow more fuel (because it's nearly open all the time anyways), THEN you've reached the point where you need to flow more during the time it's open.

Once you determine where your injectors are at, then you'll know what you need. Given your mods, I'd venture to say you're not at the point of needing new injectors yet.

Same goes for fuel rails. They might look pretty, but you won't need them for awhile. As a point of reference, I ran nearly 500hp at the wheels on my stroked 4.6l, and it ran on stock fuel rails and 39lb injectors (but probably getting close to the point of needing 60lb).
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Old 10-17-2012, 06:17 AM
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Originally Posted by siggyfreud
The amount of fuel you need is dictated by the amount of air the engine can bring in. Simply adding more fuel isn't going to give you more power, unless, for example, you're running lean enough that you're being robbed of power. If you do some datalogging via your tuner, or on a dyno, you'll be able to see what your injectors' duty cycle is at. Duty cycles range from 0%-100%. 0% means the injector is open 0% of the time. 100% means the injector is firing all the time to keep up with the fuel needed. In my experience, I haven't looked to bigger injectors until my duty cycle began peaking above 80%.

All the injectors are is a spout. You can control fuel two ways. The amount it flows, and how long it's open. So if you can't keep the injector open longer to flow more fuel (because it's nearly open all the time anyways), THEN you've reached the point where you need to flow more during the time it's open.

Once you determine where your injectors are at, then you'll know what you need. Given your mods, I'd venture to say you're not at the point of needing new injectors yet.

Same goes for fuel rails. They might look pretty, but you won't need them for awhile. As a point of reference, I ran nearly 500hp at the wheels on my stroked 4.6l, and it ran on stock fuel rails and 39lb injectors (but probably getting close to the point of needing 60lb).
Okay cool but why about after i do heads? Im planning on getting frpp heads too
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Old 10-17-2012, 09:12 AM
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Originally Posted by DTMR
Okay cool but why about after i do heads? Im planning on getting frpp heads too
That's something you'll have to determine via data logging or a dyno run. Ask the tuner or operator to specifically log duty cycle along with the other norms.
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Old 10-17-2012, 06:51 PM
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Originally Posted by siggyfreud
That's something you'll have to determine via data logging or a dyno run. Ask the tuner or operator to specifically log duty cycle along with the other norms.
awesome thanks a lot for your help
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