pt2285

ok so fuel injectors, are there any real gains to justify costs moving up to a high lbs/hr injector. can a good tuner set the dwell time in the tune or does a good upgraded injector take that same voltage and just hang open longer. please school me in the world of aftermarket injectors. thank you guys.

JoeNova

Larger injectors provide more flow. If you're not maxing out your current injectors, going to bigger ones aren't going to show you any gain...

pt2285

how does one know if they are maxing out their injectors without being on an engine dyno or etc...

ss.slp.ls1

iTrader: (36)

If you aren't examining the injector duty cycle with tuning software then you only have your horsepower to go off of. The more horsepower you make, the more fuel you require. You might want to consider upgrading your injectors for a heads/cam/intake/full exhaust upgrade. You'll definitely need larger injectors for nitrous and turbo applications. What are your current mods?

KCS

iTrader: (20)

There's a Fueling and Injection section with all the answers you seek.

pt2285

im sure there is, but with the amount of time it would take for me to find the answers i know there is someone itching to express their knowledge and feel like they helped someone today. some call this laziness, i call it just wanting straight answers.

pt2285

ls3 427 stroker, pat g cam, afr ls3 heads, fast 102 intake.. shooting for like 600-650HP. i have yet to buy injectors but im looking at fast 50lb/hr injectors.

JoeNova

Most scanners can tell you injector duty cycle. Whoever is doing your tune could do the same.

ss.slp.ls1

iTrader: (36)

Not totally accurate but:

(650 x 0.50)/(8 * 0.8) = 50.78. So the 50lb/hr injectors should be right in the ball park for you.

pt2285

thats how i came up with the 50lb/hr ones.. figure it would be good. but should i stay in that area or go one size up for headroom?

ss.slp.ls1

iTrader: (36)

It won't hurt to get the 57# if you are thinking that you will hit the 650 mark and you want room to grow.

pt2285

i was thinking of going with fast just because i can get great deals on them, next size up for them is 65... too much?

pantera_efi

iTrader: (1)

Hi PT, as you see from the posts NO ONE has answered your question.

I supply a DENSO injector of 450cc as common to the LS engine.(500HP)
The users state the Idle quality IS better than the OEM injector.
The REASON is fuel droplet size of 2-3 microns vs OEM of 5-6 microns.
The common newest injectors have a smaller fuel droplet size good for HP increase and a fuel mileage increase.

IF you question was as observed, I too have that answer.

An upgrade to a larger, MODERN, fuel injector allows for the fuel delivery to be MORE directed at the OPEN valve. (50%-60% Duty)
This is VERY GOOD the reduce T-fuel, allowing the engine to make more power.

The EMS/PCM must have the object, the Injection Instant that allows for adjustment to be correct.
My ECU-882C does this with advancement of injection as RPM is increased.

Fast sells injectors they do NOT manufacture, WHAT is their manufacturer ?

Lance

pt2285

im sure fast doesn't make their own injectors as to no one makes their own anything anymore. but i can get a great deal on them so thats why i was leaning toward the route. i completely understand that by using your ECU and yoru supplied injectors that the combination work well together. but im not trying to completely reinvent the the wheel on my current set up. i can also see that you are very knowledgeable and possess a brilliant mind because you speak in "tech" riddles. but basically the answer i am seeking is hey are 65lb/hr injectors too big? and what else have people gone with. thank you sir, but i do look forward to checking out your coils.

dreadpirateroberts

iTrader: (1)

I agree with Lance, proper injector pattern and aim is important. many get by without worrying about it, though.

as far as tuning, it depends on the injector. ECM software will calculate the appropriate pulse width based on calculated cyl charge, feul trims, injector data, etc. What the ECM needs is the right injector flow rate table, voltage offset values, min pulse width values, injector timing in relation to exhaust valve closing (which is based more on your valve event timing than anything else), etc etc etc.... these are all in the calibration and a good tuner will know what to fill in based on what injector he is tuning for.