Does anyone know the flow rate of the light blue topped Ford Injectors?

 

And at what PSI? Also, If I am putting the inj. flow rate in TC would I enter the corrected rate for my FPR setting with vac. line off or enter the advertised flow rate of the injector at tested pressure (even if I am not running tested pressure)? Doesn't the FP drop when you plug the vac. line back in? Seems like that would throw off the inj constant you set for flow at the fuel pressure with vac. line on.

 

Blue top Fords are 24 lbs at I believe 38 psi, whatever Ford rates them at.

 

they are 24# as stated above and.....

Ford are rated at 2.7 bar (39.6 PSI)
GM are rated at 3 Bar (43.5 PSI)

 

So 24 pph. @ 39.6 psi. and 26.4 pph. @ 43.5 psi. right?

Then I still can't understand why my car is running so lean (160 blm's) when it switches to closed loop if I am running 47 psi and have the inj. constant set to 28 pph.

 

24# @ 39.6PSI = 25.15# @ 43.5PSI
24# @ 39.6PSI = 26.14# @ 47 PSI
according to my calculations. (anyone care to correct me if i'm wrong?)


you need to lower the injector constant to enrichen the mixture. a note, this is all on a stock 350 TPI. i too was having problems with the FMS injectors running lean. my fpr is stock. no adjustments. with no access to a scan tool i had to go by mechanical and smells to figure it out. not the best way to tune but better than no "tuning" :sillylol:. on mine it would ping slightly @ wot and the exhaust smelled horrible. i had the injector constant set @ 22.78#(simulating 22# @ 43.5) since my FMS injectors are 21.6#. the car ran great but the perfomance still left more to be desired. so i setup the injector constant @ 22.32# simulating 23.24# @ 43.5) the car now longer pings and the exhaust smells "clean". the car runs GREAT. she goes sidesways on the 1-2 shift like she used to.

 

yes i also agree that you need to lower the injecter constant to richen up the mixture.but your car is far from stock and 24svo's most likely arent big enough at that pressure without massive tweaking of the prom.how much boost you running? do you have a fmu? what does your car run like at wot.im only running a 350 with 6lb boost and i have my fp set at 50psi no fmu. injecter constant set at 30 and have done alot of ajusting to get it what i think is close.built a wbo2 with my time off over christmas(hope it works) so next spring i'm sure that a few more burns will be in order.of course thats if i stick with the 7330 and dont swap to the 7749 like i am planning.
pete

 

that's what i was thinking. i believe you need larger injectors. i'm no expert but 30# should be able to handle the job.

 

I am not disagreeing with you but what formula do you use to getthe injector flow rate at diffeent pressures? That might be the reason I am getting so confused. I have some red top FMS injectors (32 lb. ???) that used to be in the car before I had prom burning stuff and I took them out because it kept fouling plugs idling.

 

I've got reds in mine. They are rated 30, but I have the constant set at 33 to get it close. Had to tweak the first MAF table to richen the idle up though.

 

There is a formula to estimate the fuel injector flow rate given the expected HP, it goes like this:

inj flow rating (#/hr) = [(engine HP) * (BSFC)] / [# of injectors) * (duty cycle)]

for an L98 engine, BSFC = 0.50
for a SC or turbo, BSFC = 0.55

example: if you expected to make 500 HP with a supercharger (SC), we have:

inj rating = [500 * 0.55] / [8 * 0.8]
inj rating = 275 / 6.4
inj rating = 43.0 #/hr

With an SC, you want to be able to run at 12.5:1 AFR @ WOT or even richer.

 

Set the Injector constant to what ever it is for the injectors your running.

If you need to add fuel somewhere then add it THERE!.

Screwing with the constant while it might make one thing better might sckew it off somewhere else. What good does that do you other then have you constantly chasin around looking for other shortcuts that don't work either.

 

Justme wrote: Use the same method used by mystikkal_69:
"24# @ 39.6PSI = 25.15# @ 43.5PSI
24# @ 39.6PSI = 26.14# @ 47 PSI
according to my calculations."

What he did different from you was to take the square root of the pressure ratio and use that as the conversion factor. You just used the pressure ratio unmodified, and it gave you a wrong (too high) answer.

 

new flow rate (#/hr) = SQRT[new fuel pressure/rated pressure] * rated fuel flow

example: flow rating of 24# SVO injectors at 48psi

new rating = SQRT[48.0/39.6] * 24.0 #/hr

new rating = 1.101 * 24.0 #/hr

new rating = 26.42 #/hr

Now this is an estimate, but is fairly close, close enough for our purposes.

 

Thanks all. Now I see where I was going wrong figuring injector flow.