19# FI limmit

I am planning on installing my N-1K, with the following modifications, F-150 crank pulley, custom discharge tube w/ a bypass, and a larger mass air meter. My engine is all stock right now but before I install the blower I want to put on headers, 1.7 rockers and an intake spacer. I will be using a 225 in tank fuel pump with an adjustable fuel pressure regulator and the supplied FMU. My question is how far can you go using the 19# injectors? Future modifications/up-grades will include an aftermarket intake manifold and a larger TB, would the 19’s still work, and be safe at this point or would this be the time to invest in larger injectors and calibrated mass air sensor? If I buy a larger mass air meter now for the 19’s, and later need to buy another one calibrated for larger injectors then I have just wasted money and time. If I should go with larger injectors now how big should I get? All input is appreciated.

well I think 19# injectors are only good for about 270 rwhp

I would get the MAF along with some 36# maybe even 42# depending on how extreme you will get with the car

My self I dont like to push injectors to their breaking point couse they will freez up on you and will blow the motor

IMHO the more fuel the better. It is great that in your mind you are thinking ahead. I agree with you 100%, why get a meter for 19's when you may need larger injectors and a calibration down the road.

I would go with 36's or 42's. If you go with the larger injector you can delete the FMU. The FMU causes lots of problems with users.

Go with a nice set of Ford 42's and a Pro-M meter and you will be ready for the new power!

Ian

For your application I would suggest the following...

36# or 42# injectors
NO FMU
A Good DynoTune
Mass Air Meter Calibrated for the size of the injector you choose.

One thing you must keep in mind is that with 19# injectors you have really no vast room to grow in terms of other major
bolt-ons, to supply the fuel requirements that will be imposed by such upgrades.


If you buy a bigger mass air meter NOW, you will end up spending 30+ dollars to have it re-calibrated LATER on when you buy bigger injectors.

Try to go with bigger injectors so that you won't have to run an FMU and you can also look at this point as well... With bigger injectors like 36# or 42# you have VAST ROOM to grow in terms of performance part addons that will impose more fuel to be supplied because of such upgrades (it could be bigger heads, more boost, whatever!!!).

As you add horsepower the demand for fuel will go up in terms of need/want. You MUST supply the fuel that is wanted from your application to avoid leaning out your fuel curve drastically.

In terms of money, look at getting bigger injectors and a mass air meter (calibrated for such injectors) as a LONG TERM investment(looking at the big picture) versus looking at the short term effect.

Regardless, you will still have to cough up money now or later, and possibly more later if you don't do it right from the start and try to save a few pennies now and thus spending dollars later.

Hope this helps!:)

Thanks guys, but if I were to put 36's or 42's on it now wouldn't be super rich with just the blower, headers, 1.7's on an otherwise stock engine? Or would I be able to reduce fuel pressure enough for it to be ok?

I ran 36's on my car with a just the blower and headers. I would suggest you get an adjustable fuel pressure regulator.
Doug

Due to your lack of mods with heads and such, I wouldn't go any bigger than the 36lb injectors. The 36's will have plenty of room to grow on your car. 42's give you the most room, but part of the problem they create is becausse they squirt so much fuel, you have to cut the fuel pressure into the 30+lb range to keep the car from running to fat at idle. This in turn creates another problem as the low fuel pressure doesn't allow the injector to atomize the fuel the way it was intended (doesn't spray a nice fine mist) Most fuel injectors are designed and intended to have at least 40lbs of fuel pressure behind them to function optimally.

However you can get around that with a custom tune on the computer where adjustments to idle can be made electronically. It depends if you want to go that route right now as you can get this car running really nice with a "mechanical" tune.

One of the reasons I mentioned the 42's is that the 36's are very rare as they do not make them anymore.

A chip, and a good mass air meter will be perfect with 42's. Yes you will be over injected for now, but you have to think ahead.

Ian

Quote:

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Originally posted by 88cobra
One of the reasons I mentioned the 42's is that the 36's are very rare as they do not make them anymore.

A chip, and a good mass air meter will be perfect with 42's. Yes you will be over injected for now, but you have to think ahead.

Ian

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yea I agree but you will have all the injector you will need

and you wont be over working it so their is less chance of a injector freezing on you