appropriate injector sizing
 

Hello all
I need a little help with my injector set up. I've been searching and reading everything I can but I want to make sure I have things correct before I go any further. Currently my motor is being rebuild and am going single turbo Precision 6262 & Haltech Elite 1000. I'll also be using the Xcessive LIM and a CJ 4 port fuel rail & rx7.com fuel pump. My initial thoughts are to run cleaned and tested stock 850 injectors in a modified primary rail & run 4ea ID1000 or FIC Bosch 1000 in the Xcessive manifold. My hp goals are modest right now (400 or so, street car) but am really trying to over build for reliability:) and if I ever want to increase power down the road to be able to. From the calculators out there it seems this will work but I know there are more things that I do not understand like injector staging etc. Is this a good set up or do I go with something like stock primary and ID2000 and plug the 2 other injector ports on the manifold? Any guidance would be appreciated.

You have modest goals and should use a modest fuel system.

Stock primaries, ID 2000 secondaries, stock intake manifold. Save the money for something else that will inevitably need to be fixed or upgraded.

Thanks for the replies so far. I did use the fuel calculator previously so based on that I should be ok. In regards to the modest fuel system, I'd like to over build some what so I can increase power latter on. I already have the excessive lower, fuel pump, rails and elite ready to be installed. The last part of the equation for me was the actual injector sizes since I thought staging large secondary to stock primary can be a challenge plus mixing old injectors with new I was unsure about that. I think I'm going with the 4 1000cc secondary and go new 750 primary just to keep everything the same and hppefully not have to worry about upgrading latter.

Are you sure you want to have 3400cc of fuel capacity going to the primary runners and 2000cc going to the secondary runners ?

Think about it...look at your Xcessive manifold.

"My hp goals are modest right now (400 or so, street car) but am really trying to over build for reliability and if I ever want to increase power down the road"

there are a number of ways to approach fuel system sizing. i favor running enough fuel so you can match your turbo air output.

the P 6262 is approx a 550 max (rotary) rwhp turbo. 73 pounds of air per minute so you are looking for 7.3 pounds of gasoline per minute. 10.0 AFR is an arbitrary number but allows for slippage and a low AFR at max air flow.

7.3 / 6.35 = 1.15 Gallons per minute = 4353 CC per minute X 1.35 for Gross injector capacity to match your turbo

5876 is your number.

stock primary ports are tiny. if your primary ports aren't enlarged i wouldn't be a fan of too much fuel thru them V secondaries. you can add primary fuel to the extent your primary ports are enlarged.

i recommend plugging two of the secondary rail ports and that you run a total of four injectors to keep things simple.

if your budget allows, i highly recommend you run Bosch EV 14 primary injectors as they atomize way (way) better than the original injectors.

Howard, thanks for the math. Its great to see the caculations so i can learn as well. I am going to use the EV14 injectors. Do you think I'll still be over fueled if doing a medium street port with 725 EV14 primary and the 4 1000cc in the xcessive lower. That puts me close to the 5876 with those injectors at 5450?

sure, you will be fine... you won't regret stepping up to the EV14s.