Injector size for MY setup?

[Defcon92]

Hello guys I was curious about some injectors and what fuel pressure I should run them at.
My setup is a mopar 230ab cam w/ 1.7 roller rockers, ported head. 9.2:1 compression. 3.500" stroke & .060 over. 4.2l mini


My jeep is a 1992, I think it has 39psi fuel pressure. It's currently on stock injectors which Dino list as 21lbs.. For injector upgrades I was looking at 703s, which are 22.5lbs @ 49 psi? With my 39psi they would be 21.5lbs, which probably isn't enough fuel for my motor. I was thinking of upgrading to the later style 49psi fuel pressure regulator which puts me at 23.9lbs?

I'm using this calculator.
http://www.witchhunter.com/injectorcalc1.php


This is confusing.

[rainman]

703 are 238cc at 3 bar /43psi not what you wrote.

Suggest you try,
703 and an adjustable fuel pressure regulator.
703’s @ 49psi work quite well on 4.6 strokers.
Adjustable map sensor output might also help with the final tuning.
Good luck with it.

[Cheromaniac]

Hello guys I was curious about some injectors and what fuel pressure I should run them at.
My setup is a mopar 230ab cam w/ 1.7 roller rockers, ported head. 9.2:1 compression. 3.500" stroke & .060 over. 4.2l mini

My jeep is a 1992, I think it has 39psi fuel pressure. It's currently on stock injectors which Dino list as 21lbs.. For injector upgrades I was looking at 703s, which are 22.5lbs @ 49 psi? With my 39psi they would be 21.5lbs, which probably isn't enough fuel for my motor. I was thinking of upgrading to the later style 49psi fuel pressure regulator which puts me at 23.9lbs?

You could keep the stock 39psi regulator and use Accel 24lb injectors. At 39psi they'll flow 23lb/hr which would be just about right for your set-up.

[Defcon92]

Hello guys I was curious about some injectors and what fuel pressure I should run them at.
My setup is a mopar 230ab cam w/ 1.7 roller rockers, ported head. 9.2:1 compression. 3.500" stroke & .060 over. 4.2l mini

My jeep is a 1992, I think it has 39psi fuel pressure. It's currently on stock injectors which Dino list as 21lbs.. For injector upgrades I was looking at 703s, which are 22.5lbs @ 49 psi? With my 39psi they would be 21.5lbs, which probably isn't enough fuel for my motor. I was thinking of upgrading to the later style 49psi fuel pressure regulator which puts me at 23.9lbs?

You could keep the stock 39psi regulator and use Accel 24lb injectors. At 39psi they'll flow 23lb/hr which would be just about right for your set-up.

Thanks Dino. Idk the math behind it all so I use the calculators which must be off. What's the 703s @ 39psi? & what are they @ 49psi?

I'll be using a safc ii to tune this thing I believe. Ryan said he can't tune obd1 ecu's so I'm gonna work with him on a safc ii to run this jeep.

[rainman]

If I were you I would be Talking to to Ryan about it.

But 703 run fine in stock 4.0's @ 39 psi /21.5 lb
As well as in 4.6 strokers @ 49psi. /24.1lb.

So I'm thinking that 703 in a 4.2 with a adjustable fpr like hesco sells should get you there.


Have a read of this there are a couple of options you could use
You can also get 55psi fpr's don't know if you would want to go that way though.
http://www.ausjeepoffroad.com/forum/sho ... ostcount=1

Good luck,