I am in the middle of an upgrade of the heads and cam on my 86, and I have a couple questions on injector size and fuel system that I was hoping for some input on. I currently have a Vortech A-trim S/C with upgraded pulleys and an FMU, 24 lb/hr injectors, 255 lph in-tank fuel pump, Pro-M MAF conversion with 89-93 ECU, DiabloSport chip, and Cobra upper and lower intakes. I am now going to TrickFlow TW Street heads and an E303 cam.

Someone suggested I upgrade to 30 lb/hr injectors and upgrade the fuel system too. Part of the reason being the way my head gasket blew they thought I was running lean. Photo attached. The questions I have are:

1. Do I need to go to upgraded injectors?
2. If I go to 30 lb injectors, do I need to upgrade the fuel system with bigger lines and fuel rails?
3. Do I need to recalibrate the MAF and/or the FMU?

I am hoping to be at around 400 HP after the heads and cam, with the potential of upgrading to an S-Trim S/C in the future. Any input is appreciated.

 

what type of chip do you have? custom? when it comes to boosted motors, any chip that isnt custom is junk. even if it is custom, when you get new heads and a cam, you will need to have it retuned.

you should be running no fmu, and 42# injectors. if you do it the half a$$ way and go with 30# you will need to recalibrate the maf and the fmu. fuel lines are fine and so is your fuel pump for the hp you are shooting for.

 

Thanks for the response. The chip is a custom Diablosport chip, and I know I will need it retuned when I am done with the heads and cam. I have been told I need to ditch the FMU, but I guess I don't fully understand what needs to be done to accomplish that. I understand the FMU is just a secondary pressure regulator that is supposed to increase fuel pressure under boost. Can the stock regulator handle that if the chip is programmed properly? Do I need a different pressure regulator? Thanks for the help.

BTW, I am in SoCal so I need to keep it CA emissions legal.

 

im in socal too. where you at?

anyways, the fmu pinches the fuel return line shut under boost. this spike in fuel pressure causes more fuel to enter the motor when its needed. your stock regulator doesnt do this, some after market regs do. if you get 42's, they flow enough fuel so that you dont need to spike the fuel pressure under boost. the tuner will adjust the injector pulse width in order to get you the correct afr under boost and during normal driving. emissions wont be effected with or without the fmu

 

I'm in North OC. So the stock fuel lines and rails will supply enough fuel with the 42s? I was thinking I would at least do the fuel rails but I won't if I don't need to.

 

[QUOTE=Raphs50;6445042]I'm in North OC. So the stock fuel lines and rails will supply enough fuel with the 42s? I was thinking I would at least do the fuel rails but I won't if I don't need to.[/QUOT

north oc? im in anaheim.

the stock fuel rails will support enough hp to split the block. no reason to swap them out.

 

Placentia