fuel injectors

[Essex29]

What injectors would you guy's recommend for a 540 ci motor?
I am converting carb to efi ( probably az speed & marine) and need to know.
thanks

[Foggerjet]

That's really a tough one, because injector impedence has to be matched to whichever ECM you're using. Injectors(usually) have power anytime the IGN. is "on" and the computer grounds them, if the resistance is wrong, POOF goes the computer. Your probly looking at something in the 50 lb/hr range, but without more info on your engine that may be bad info. AZ speed and marine know a whole hell of alot more than me, and they will surely taylor a system to fit your needs.
fog

[GEOO]

Here's a good link to help explain injector size.
http://www.rceng.com/technical.htm
(I have not talked to or used RC FI., but the calculators are great)
The fuel injection fuel system must work together.
The ECU, Fuel Pump, Fuel lines, Fuel pick up in tank, Fuel return line or Fuel cooler, Fuel Regulator, and injectors must be sized correctly to have good system. Some ECU can power low and high imp. injectors, some ECU require one or the other.
Plan your whole system out before you buy anything.
A typical FI system runs @ 43.5-45lbs of fuel pressure.

[GofastRacer]

Check these guys out!.
Kinsler! (http://www.kinsler.com/i_efi.htm)

[396_Z]

Dealing with the 305,350/355, and 383's that my friends and I run in our Camaros I've found a simple trick to give me a starting point for injector sizing.
For reference, a stock 305 TPI comes with 19 lb/hr injectors, a 350 TPI comes with 22 lb/hr.
305 divided by 19 = 16.05
350 divided by 22 = 15.91
Through trial and error I've found 24 lb/hr injectors work best on moderate 383's in our applications (aftermarket TPI style systems).
383 divided by 24 = 15.95
Now if I'm right and it is really that easy then sizing a mild 540 would be like this:
540 divided by 16 = 33.75
Giving aprox size of 34 lb/hr. That works out to be 15.88. If you can't get 34's or if you think your a little above mild then go with 36's. (which works out to 15 CI per lb/per hr. rather then the 16 everything else has been hovering close to.)
Lastly you can always fine tune once you get close by adjusting the fuel pressure up or down a few lbs.
Did I confuse anyone?