Injector flow = what HP?

[Billiam500]

does anyone know how to figure out what amounts of power an injector will support given its flow? I heard that the injectors in HO 302's flow 55lbs/hr and can support 100hp/injector.

[thelostartof]

all CFI 5.0's were HO. and they all flow around 46lb/hr @ 3 bar(green tops) the rare tan tops flow arounbd 52lb/hr @ 3 bar

no idea on hp but i do know many have made 300hp on 450cc injectors just fine

[Billiam500]

I'm almost certain the mustang I saw at the JY was PFI.:???: What are the 450cc ones?

[thelostartof]

the 5.0 HO's that are EFI injectors only flow like 19lb/hr so

[benflynn]

i thought that there are 2 types 36ish(out of the cfi v6's) and the 53@3 bar 6x@4bar(in v8 cfi's) there are probably 15 of each at the pullapart here

[frpe82]

This page can´t be right: Injector selection guide (http://www.injector.com/injectorselection.php?PHPSESSID=37e7e9693ba51f3689 059c8f88a6b440)

Rediciously high lb/hr just to get to 200HP.

[n xntrx volvo]

theres info/ calcs in the fuel faq.

[frpe82]

So, how much would a set of 42lb/hr really be capable of?

[thelostartof]

42lb injectors most can get 300hp out just fine tho it all depends on tuning

[pbonsalb]

Roughly 1/2 lb of fuel per horsepower per hour for non turbo cars. Turbo cars generally need 10% more fuel for cooling. 42 lbs/hr injectors with 1/2 lb per hp equals 84 hp each potential, and about 8 hp less for a turbo motor or 76 hp each for turbos. Multiply times the number of cylinders for total power potential.

This is at 3 bar or 43.5 psi pressure. Very roughly, raise the pressure by 50% and you will gain 20% in flow.

Low impedence injectors can run safely to 100% duty cycle -- which is the duty cycle for the flow rating. High impedence injectors should not be run to 100% duty cycle -- 90% is probably the maximum safe limit.

The CFI injectors are low impedence (around 2 ohms). High impedence injectors are around 12-16 ohms resistance between the two terminals.

The Ford "browntops" are around 37 lbs hr or 400 cc/min and are low impedence. Figure roughly 74 hp each non turbo or 67 hp each for safe turbo use, or total safe potential at 3 bar of 4 time 67 or about 270 hp.

If you think you may be running your injectors near flat out, beware of going lean. Invest in a wideband or EGT meter or, better, larger injectors. I have seen EGT soar, have blown headgaskets, overheated valves, cracked heads, etc.

Philip Bradley

[Billiam500]

Ok, I got what I needed from the faq. But are all Low imp. injectors the same-could i use the volvo 6 ohm ballast resistors?(this is going on a MS car)

[242GTMD]

http://forums.turbobricks.com/showthread.php?t=59090&highlight=Injector+Sizing

:)

[pbonsalb]

Yes, you can use other or aftermarket low impedence injectors with the Volvo or similar resistor pack that is found on turbo 7/9 series. Theoreoretically, the resistor pack may not be as good as a flyback board for the MS, but in practice, the difference is probably not measurable. If anyone knows more about that subject, I would be interested. In theory, a true peak and hold injector driver should be superior to a standard driver fitted with a resistor pack in the injector power feed.

Philip Bradley