LT1 injectors Q

[gradon]

I'm running the lt1s on my stroker. They are rated 24#@43.5psi, so on the 49psi rail, they flow 25.5#.

 

[bigdaddyjlove]

The pressure of the system should be controlled by the regulator, which should have come with the fuel rail. So If I'm understanding what you did correctly, your fuel pressure should be 39psi, no matter what pump is used.
Now I need to go study some more fluid dynamics because I still don't understand it all.

Later models came with the fuel pressure regulator in the tank and they are set at 49 psi

 

[BlueCuda]

What do the ford flow at 49psi?(24lbers)

 

[gradon]

I believe the blue tops are rated 24#@39psi. On a 49psi rail, they are 26.9#

 

[POLAR_JEEP_04]

so what do LT1s flow at on a 97 4.0 fuel rail?

 

[seanyb505]

Post #21. "...on the 49psi rail, they flow 25.5#."

 

[POLAR_JEEP_04]

must have missed that... thanks

 

[RedChuck]

maybe i missed it but what is the part number for the lt1 injectors

 

[maybe2fast]

!!!!! 93 lt1 injectors are different than any other LT1 injectors

 

[gradon]

what are they rated at and do you have a pic?

 

[maybe2fast]

1993 LT1 cars use 22# injectors
1994-1997 car used 24# injectors

1993 Firebird LT1-1997 Firebird LT1
Ignition ON Engine OFF 41.0 to 47.0 psi
With Regulator Vacuum Applied [1] 3.0 - 10.0 psi less than Ignition ON Engine OFF
1996 XJ 4.0
Engine at idle speed 338 kPa ±14 kPa (49.0 psi ±2 psi).


This tells me that my 94 injectors on my 1996 XJ are way too big. At 49psi the 94 lt1 injectors are flowing way to much than needed for a stock 4.0 with simple bolt ons. The 93 injectors at 49psi may be the best option when you don't have a stroker needing the bigger sprayers. My xj runs great but the trims in the computer are pulling fuel and might require a replacement this winter with the proper #age.


I am going to be doing some research into the 3800 engine injectors to see how close I can get to the stockers but keep the multiple spray noozles for the increase in throttle response.



I have always thought that when the ecm is pulling that much fuel it is in a table in the ecm fueling that you are not getting the best possible running the ecm can give you.

 

[maybe2fast]

Series II 3800
L32 injectors are rated for 31.5 lbs/hr @ 60psi

SC3800
L67 injectors are 36.5lbs/hr. @ 47-52psi

way to big for us.

Series I 3800
L27 does run 41-47 Psi
L27 injectors are 21 lbs/hr.

 

[hawk_sixsix]

I have a set of 93 LT1 injectors.... somewhere.... :looney:

Any reason not to install them on my stock 97 XJ 5-spd with full 2.5" Magnaflow exhaust? If I read this thread correctly, it would be a small but noticable upgrade, within the fuel-trim parameters of the PCM.

(Right?)

 

[bigdaddyjlove]

they should provide a little better throttle response, maybe a smoother idle. no reason not to, its easy, just don't expect a huge difference on a (mostly) stock motor

 

[hawk_sixsix]

Well hopefully it won't always be stock. I'll put 'em in and post a report. Thanks!

 

[-96JeepSpeed-]

So what are the absolute best injectors to run in a 4.0 with simple bolt-ons? I can never seem to find a stright anwser for this...

 

[gradon]

I thinks it's because no one person has tried multiple sets of injectors to see which set worked best.

 

[gradon]

Hey Hawk, can you post pics of the 93s before you install them?

 

[-96JeepSpeed-]

I thinks it's because no one person has tried multiple sets of injectors to see which set worked best.

Exactly what i mean..

 

[Johnnie Walker]

2 most common are the Ford yellow or orange tops (for 5.0L) and the 93 LT1's they both atomize fuel better, and flow pretty much the same. So take your pic.