chpmnsws6

iTrader: (70)

Just as the title states, what is the lowest fuel pressure you can run on an injector before it gets an erratic spray pattern at atmospheric pressure?

I am running 03-04 cobra injectors on an L33, so I was thinking about running a lower pressure to help with idle tuning and such, plus its easier on the fuel pump (and will flow more at the lower PSI).

Thanks!

bww3588

iTrader: (49)

im not 100%, let me go talk to Frichie and see what he has to say.

69LT1Bird

iTrader: (1)

Those injectors are not made for our engines. The have a 30* cone pattern that washes the front and rear walls of the intake port instead of hitting the back of the intake valve.

Changing fuel pressure is not the right way to tune. Get the right injectors, put the correct injector data for those injectors in your tuning software and tune it.

Call Jon at FIC fuelinjectorconnection.com He will take care of you.

bww3588

iTrader: (49)

not neccessarily. you can dial in fuel pressure. he is not trying to change the injector rate or anything like that, just to keep strain off the fuel system mostly.

one thing you have to watch mike, is the intake tract has pulses from the firing of the engine. you have to make sure you have enough fuel pressure for the spray pattern to overcome thoes pulses and still spray like its supposed to. think about it like this, pissing into the wind, if you dont **** hard enough it will come back and soak you. lol

69LT1Bird

iTrader: (1)

I would be easier to do it right the first time.

jimmyblue

iTrader: (11)

Well, last I looked the Fords were still 3-bar so 40PSI
ought to be "no surprises".

Question is, how well the "fuel model" matches the fuel
shot reality - PCM has a pretty lame idea of what true
pressure is, unless you have a manifold referenced
regulator close-in.

chpmnsws6

iTrader: (70)

It is a vacuum operated fuel pressure regulator sitting about 12 inches from the back of the intake manifold. The injectors are freshly cleaned 03-04's being suppied by an aftermarket rail, Aeroquip AN-6 feed, and a Walbro 255 high pressure pump..... Its ready for anything I want to throw at it, but right now I'm only going to be throwing 350-370rwhp which STOCK injectors can still handle, let alone an injector that flows 47 lb's at the stock 60psi.

BWW3588- Yea, I've pissed into the wind enough on this project...... No need to do that anymore!

69LT1Bird

iTrader: (1)

You are not going to overcome an incorrect spray pattern by backing down the fuel pressure. You will just get more un-atomized fuel in the wrong location.

I speak from experience, I ran those when I first built my current setup. Ran OK but was somewhat inconsistent tuning. I took the intake off to look at a knock sensor and saw that the front and rear walls of the intake ports were spotless, the injector angle was so wide that it washed the ports which in turn will cause the fuel to puddle on the valve, that leads to inconsistent fueling.

There are much better injectors to choose from, you can easily sell the SVO ones and just get some LS1 injectors that are sized correctly, have the correct pattern, and the injector data is already on the PCM so tuning is easier. But what do I know.

chpmnsws6

iTrader: (70)

Which do you recommend?

*Edit* I'm an idiot..... Guess I'll read more before I post

69LT1Bird

iTrader: (1)

Call Jon, he may work a deal and take the SVO 39's off your hands.

chpmnsws6

iTrader: (70)

After talking to Jon, I will NEVER go ANYPLACE else for injectors!!!

69LT1Bird

iTrader: (1)

Good guy, honest, and doesn't try to sell you stuff you don't need and stands behind his product. Gotta like that.