b18-c-rx

i'm looking at 550 cc RC injectors for my ~280 hp b18c. my calculations show me that
a. this is the right injector size for 80% load and
b. i only need a 190 lph fuel pump, not 255.

my questions are:
1. is my 550 cc/min injector size too big
2. why does everyone use 255lph fuel pumps, it doesnt seem necessary for any of their applications

093turbo16

iTrader: (2)

255LPH isn't necessary in most ocassions, but you never know where it will go. And 550s will be fine, just in case you want to build more power. But 450s or 440s would be ok too.

b18-c-rx

is there an issue with getting too big of a fuel pump (bad idle, for example)?
also, i read somewhere (i think it was a. graham bell) that injectors work best when at .60 duty cycle in sequential applications, so the 550s may be better. if i tune it right, larger injectors shouldnt be a problem, correct?
also do I want the high resistance or low resistance injectors? =p

093turbo16

iTrader: (2)

Exactly, you can't tune with fuel you don't have... So leaning them out is the best way to do it, except for possible idle problems, but it should be ok, definitley many people running 550cc+ injectors.

b18-c-rx

thats what i figured. so is there no issue whatsoever with the fuel pump?

093turbo16

iTrader: (2)

shouldn't be. Do you have anyway to monitor the pressure. After doing any fuel mods, a fuel gauge should be in your future.

b18-c-rx

oh yeah, my fuel pressure gauge tells me i'm dead on right now, but i'm planning out my turbo setup, so i dont really know. all i know is that 450cc/min injectors seem to be pushing it in terms of duty cycle, as my calculations show me that i need 500 cc/min for .80 duty cycle.
that is assuming my fuel pressure is 52psi - is this too low, should i plan to run higher?

97hb

I am running the 255hp walboro and rc 550s. My duty cycle at 300whp was about 84%. I got a good deal on them, but will be upgrading soon

b18-c-rx

any rough idle/bad driveability issues?

what kind of deal is this, pray tell