Injector ?

[93SlugTT]

I am second quessing my injector size for my build. would like your thoughts.

as of right now i have 750cc injectors, i have been rethinking this and thinking i will need much bigger since i have went to 15g turbo's.

the engine is semi-built. turbos will be 15g's with a fmic, aem ems to tune, speed density. now the kicker will be on E85 and i will be pushing as much as the 15g will go thinking 23psi maybe higher if it will do it without tearing down the turbos in a pull.

your thoughts. 750's to small, i think so since e85 burns 33% more then normal gas. so maybe 1000's?

[UTRacerX9]

That should be about right actually, since the 15g is optimally paired with 550cc injectors for regular gas. 550*1.35= 742.5cc

If you find it's not quite enough, getting an AFPR will allow you to increase the pressure to make them perform as a larger injector would.

[93SlugTT]

already have a FPR along with running 2 walbro 255's , so my first choice was right and second quessing myself isnt helping me lol

[UTRacerX9]

If it helps, VR3.9 is running E85 and is running PTE780's, which, from what I've heard, actually flow a bit less, like 750. (I used to have PTE680's, because they flowed as much as RC660's.) He upped the fuel pressure a bit to 55psi to make over 500hp.

[93SlugTT]

i want over 500 lol. are you running 15g's as well? sorry i haven't been on the site much so i don't everyone's set-ups.

[UTRacerX9]

No, I have 13T's and RC550's. Wasn't planning on using E85, but after seeing VR3.9's numbers, I may consider changing in the future if I can't hit my goal with the setup I have. (11.6 on pump gas.)

I doubt you'll hit over 500 with 15g's. The 13T, while a similar sized wheel, is more efficient.

[93SlugTT]

i bet i tap 500 on the mods and boost levels i am going to run. having blow though intakes, aem ems, speed desnity, full exhaust, fmic, e85 ,

block weisco pistions, arp head studs, main bolts, rod bolts. allowing me to push the turbos to whatever i want. i better hit 500. there isn't a reason i shouldn't. there was a guy who just hit 503 on 15gs on a maf-t at i think * 18-19psi.

[UTRacerX9]

Let me revise... I don't think 15g's are good for a significant amount over 500. Sure, 500-515 is possible, but they're maxed out at that level. There's only so much air they can move.

[93SlugTT]

ahh, yes i agree. i just want the 500 or over mark lol. be nice to hit like 545 or something but it wont happen. but 510,504,515, 501.9 im happy with lol. 500 whp makes for a fun car.

[futurevr4man]

something interesting to think about...

just because your datalogger says 100% IDC doesnt mean you are actually using 100% of your injectors. i mean, you cant use more than 100% of what they can give yet it can read higher than 100%.

my point being, you will have a little headroom methinks