I have a 93 z28 automatic that i just rebuilt. I had the motor bored and stroked to a 383. I used a forged crack, 6" H-beam rods and and forged dish pistons. My heads have been CNC ported and Bowl blended. They contain a 2.00"/1.55" valves with aluminum 1:5 race rockers. My cam is a comp cam 220 ink 230 ext with .510 of lift both ways. I have in stalled a BBK twin 58 mm throttle body and am ABOUT to purchase an LT4 intake and have it port matched to the throttle body and add an adjustable fuel pressure regulator. I just dont know what size injectors i should go with. My car dynoed 320 to the rear wheels with the stock fuel system. but that is before me adding a port matched intake and heads and adj fuel prssure reg and injectors. So if anyone could help me figure out what size injectors i will need in the end i would greatly appreciate it. I also have the SLP y-pipe headers and no converter with flomaster exhaust and a MSD digital 6 ignition. I also have a 150 shot of NOS i have considered using, but i might not use the full shot maybe just 100.

Thanks
Ryan

 

I did basically the same as yuo and a hell of a lot of research. I ended up going with 30#'s. Unless your gonna be Blown and pulling 500+ HP, the 30's are perfect.

 

i'd go 30's.

 

Another vote for 30lb injectors if you plan on spraying your car. Do you plan on upgrading your fuel pump?

 

Wet or dry? That will determine if the injectors need to be larger.

 

Im running a dry system. I hopin that upgrading my whole fuel and air delivery system will give me a very noticable difference. I am also adding a H/V fuel pump. If anyone knows any tips or hints to getting HP to the ground help me out. I race my big rival next year when the strip opens and i wanna burn hi bad enough he'll shut his mouth. He has a 2001 supercharged Mustang 5-speed with 4:10's. Also does anyone know where I can get my tuning of my computer done? The 93 camaro uses a PCM unlike the 94 up where you can use LT1 edit.
Thanks
Ryan

 

If its a dry system, and you are running the stock ECM, how do you plan to add the extra fuel..... increased fuel pressure?

I agree with everyone that the 30# injectors should handle your NA requirements just fine, but how you add the extra fuel in the dry system will determine whether you need to step up any more than that.

 

Im tryin to understand this so bear with me,,,are you saying that i need to tune my motor for use without nitrous and then when i ise nitrous have a way i can change the setting for more fuel? Also do i have high impedance or low injecors?

Thanks
RYan

 

Mine is still a stock bottom end, but the rest of the combination is pretty similar. I'm using 30# Accel injectors in mine, which seem to be working out well for me.

Frank

 

Ild go with svo 30#. That said your stockers are probably adiquit since your running a cc305 and 1.5 rockers NA. The SVOs are better than the multec for nitrous use IMO.

 

What do you mean by a cc305? Is $220 for a set of 30# svo's? high? also i have considered going from an auto tranny to a t-56 for fear that my tranny will not hold. It has been rebuilt with heavier springs and all that garb but they say that the 700-r just wont hold all the HP im waning to run. But i dont want to lose OD by goin to a TH 350 so i thought about goin to the t-56? What do you all think?
thanks
ryan

 

Your cam is a CC305...220-230 / .510". I'm using 1.6 rockers on mine, though, so I'm running .544" lift.

As for the transmission? I run 12.0's with a 700. I'm taking mine into the 10's next year with the 150 shot of NX. I build transmissions for a living...I've got 700's out there in the mid 10's.

Frank

 

Yes... you tune the ECM for NA. Then you need a way to boost fuel flow through the injectors when you spray (and a way to pull timing). The NOS-5176 dry kit, for example, puts a pressure signal from the nitrous line against the vacuum connection on the fuel pressure regulator, and boosts the fuel pressure to 85-90psi, which increases fuel flow by about 40%. But that pressure is based on the assumption you are spraying 125-150HP on a stock injector, and if you choose a different injector, you have to fiddle with the fuel pressure boost.

I run a 275 dry shot, but I have an aftermarket ECU that has programs for both NA and nitrous in it, and switches to the nitrous program when the system is armed. 64# Bosch injectors running at 58psi (=78#/HR).

Your stock ECU is intended to drive high impedance (12-15ohm) injectors. That's what the stockers are. You can go up to 42#/HR, as I recall, and then you would need to go to an "add-on" box that is available to allow the stock ECU to drive larger, low impedance injectors.

 

Another vote for 30# and please don't say NOS