waterdog

I installed a used radix which had a 2.8 pulley and 44 lb injectors on my 6.0 lq9. It came off of a lq9 as well. The previous truck had a stock cam and manifolds with a free flowing exhaust. The injectors were at 75%. My truck has a 212-218 low lift cam and long tube headers. This cam isn't that big for a 6.0L, it idles like stock. I also installed meth inj using washer fluid because its in my washer fluid reservoir and I dont want 100% meth spraying on my windshield. Just wondering if 44lb injectors may be big enough, I dont want to buy 60s if I dont have to and I dont have a wide band yet.

kbracing96

iTrader: (26)

You'll be at the very top of what those will flow. What year is your truck? A return fuel system will let you make a little more with them, but 500rwhp with meth, is about all you can max with 44's.

waterdog

Its a 2000 with return style. Im also using an aeroforce gauge that shown knock retard, hoping it will show something if it got lean.

kbracing96

iTrader: (26)

You can also watch you narrow o2's should be in the lower to mid .900's in boost. Upper .800's is ok as long as your not getting any KR.

waterdog

Thanks very much, Ill watch that as well.

krambo

iTrader: (4)

Here is a "guideline" for injectors:

1. Take your target peak horsepower (FW) and multiply by .6
2. Take your resulting number and divide it by 8 (number of cylinders)
3. Take that number and divide by .9 (corresponds to a 90% IDC)

The final result is your desired fuel injector flow.


If you wanted to calculate a NA motor instead of your supercharged motor, you multiply by .5 in step 1 and for turbo, multiply by .625.

Mort

Is that formula designed to apply to our working fuel pressure of 4 bar or the 3 bar most injectors are rated at?

Tks.

waterdog

Good to know. Thanks for the info.

krambo

iTrader: (4)

Doesn't matter. The end result is the flow you need, weather you have 20psi in the rail or 58, as long as the injector flows the end result of the formula. Case in point, my motor requires a 42# injector according to the formula however I use a 36# rated at 43psi. At my rail pressure, they flow roughly 41.

LsxCody

iTrader: (3)

thats a good formula