Bigger fuel injectors question

Car: Ford, Mustang, 2004, 3.8 V6 - Back to Fix-It - Ford Repair Manuals

Q.I am going to look at and install larger fuel injectors for my 2004 v-6 mustang. I have dual flowmaster kits with 2 and a half in piping. A bbk cold air kit, a bbk 65mm throttle body, bbk shorty tube headers, I don't have the $ to put a supercharger on so my question is, am I on the right path and if so how much lbs injectors do i get and could you possibly tell me how much HP could i get from this.

Will i need a tuner? I did use a diablo tuner and a sct before with 96 or so octaine. we put it on a dino and gained only 4 HP. Hopefully bigger injectors will help if and when i ever get my supercharger

Answer You do not want to increase the engine fuel supply until you make a much larger increase in the engines ability to use that fuel.
Here is how to look at it. The engine is a air pump. The more air in and the more air out, the more Horsepower you are going to make. When you supply more air, you will have to supply more fuel.
With a stock 4.0 SOHC, you have opened up the inlet and outlet, but the engines restrictions are at the cams, heads, and engine design.
The only way that you are going to easily increase the air flow into the engine, is with pressure. Turbo or Supercharging.
Save your money, until you are ready to put on the supercharger and then install the injectors and the programmer that the company that makes the supercharger recommends.
Unless you have true access to a dyno and are willing to spend a lot of time maping and tuning, you are just guessing as to what the engine needs.
If you added the parts that you have and the check engine light came on and gave you a lean code, then the engine computer has compensated for the amount of air that you have added by increaseing the injector on time. It will take a pretty good amount of additional air to fall out of the computers ability to add fuel.
Also note: higher octane fuel does not have as much energy as lower octane fuel. That means that unless you have raised the compression on the engine, running 96 octane is a loss for horsepower. It allows you to run more timing, but the computer will already do that with the knock sensing ignition system. As long as the engine is not pinging, then you do not need the higher octane fuel. Period.

Addition Thank you for a educated response. Im not sure if I told you but here we go anyway. I have a bbk cold air kit, bbk throttle body, bbk shorty tube headers, and a dual flowmaster exhaust. I have done tuning. A sct tuner. We threw it on the dino and it got 4 amazing horsepower. I was not happy and returned it. So with that in mind since i almost completed air flow without supercharging am i going to get help from these injectors?

Answer Again, No, Changing the injectors, without increasing the engine ability to pump air will not help.
Again, the limit for the engines ability to use air, on that engine, is not the throttle body, or the exhaust system, but the engine it self. Unless you change the ports in the heads, change the cams, change the compression (all mechanical chnages) you are not going to need the fuel that larger injectors will supply.
Look, you have a 4.0 V6 that produces over 200 hp in stock tune. That is a considerable amount when you look at the fact that, when the Mustang came out in 1979 (the first year of the Fox body Mustang) with the 5.0 the engine only put out 124 hp. From a 5.0!
Again, you really have to use the components that the SuperCharger Manufacturer recommends. Most of the blower kits out there come with injectors, and all the stuff that they want you to use. This is because they have spent a considerable amount of time, on the dyno, testing and mapping to make sure that you are going to get their power and still be reliable.
Unless you are going to build your own system, then use their stuff.

Addition Ok I understand now. Thank you. Im sure it doesn't make a difference but she's a 3.8. Since theres no way i can afford a supercharger maybe i should be shopping for a camshaft like you suggested for compressong air. I'm not savy when it comes down to upgrades ect thats why i joined this club. I have many questions but i will keep it mild. I still need to put pulleys on. Like a cam or something what would be my bigger bang for the buck.

Addition Shall i do that then? Your info has been very good. I will eccept and move on as soon as i hear from you and be out of your hair.

Answer It makes a huge difference.
I cannot stress this enough.
Do Not Attempt To SuperCharge that engine unless you go inside and upgrade the internals. Especially the head gaskets and head bolts.
That engine has a tendency of blowing head gaskets as it is. Under pressure you are building a hand grenade and just waiting to pull the pin.
The 3.8 is a push rod engine and can be made to produce a considerable amount of power. But it takes a considerable amount of work.
The 4.0 is a Single Over Head Cam engine and is a completly different design. But doesn't have the weakness of the 3.8.

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Bigger fuel injectors question