i been searching thew this all day and want to know what size injectors to run
set up

stock b18c1
t3t4 garret turbo 60 trim .63 a/r
revhard manifold
hondata
aem fpr
walbro fuel pump
etc...
running 5psi on the streets and 10psi at the track

i keep reading 440 will be enuff but then i read 550 is needed
i'm thinking 10psi is good enuff for 280whp-300?

but i read somewhere that if u got fmu 12:1 suttin like that u only need 310 injectors

i am lost cuz i am new to boost
help me out!!!

 

550's, better to have to much than to little

 

Don't worry about fmu's your not using one nore do you need one.
Go to rc's web site it has a injector flow calculation worksheet. But I would recomend 550cc so you have a little room to grow if you need.

 

Go with 550's if you plan to run anywhere near 275-300 whp

 

I have a set of MSD 520cc injectors I will sell. E-mail me-- ksf2216@tntech.edu

 

aren't 440's good till 300whp?

 

get bigger, so if you want more power you dont have to buy more injectors

 

To determine the size of the injectors, the total engine power must be estimated or known. The fuel pump calculations and BSFC information mentioned in the previous section provides a good understanding of the fuel requirements for an engine. The following equation will allow you to determine the requirements of your injectors:

· Forced Induction engines have a BSFC of .65 to .68

Using the same engine as above:

· ((Power x BSFC) x (1 + Safety Margin))/Number of Injectors = pounds/hour
·
An example of this equation is:

· 6 CYL. engine rated at 500 hp on gasoline using moderate boost with a 15% safety margin on the injector
· 500 x .625 = 313 lbs/6 = 52 lbs/hr/ injector. 52 x 1.15=60lbs/hr/ injector

If we take the flow of the injector (60 lbs/hr) and multiply it by the number of cylinders (6), we arrive at a total of 360 lbs/hr of flow. As you can see, the fuel pump described above has enough capacity to feed the engine with a little room to spare.

It is a good idea to know the maximum operating pressure of the fuel injectors. In some cases the fuel injector will not open if the fuel pressure exceeds the design limit of the injector. Also, at the higher pressures the injector fuel flow may become non-linear and cause inconsistent fuel delivery, usually creating a lean condition. Most injectors can withstand up to 70 psi. Many of the pintle style injectors can withstand higher pressure.

In the fuel injector sizing, always use a safety margin between 15-20%.

~~~THIS IS TAKEN FROM http://www.aempower.com~~~

 

Just go to http://www.rceng.com they have a worksheet for going both directions. (Known power, and known injector)

 

440's will be perfect... I have friends running 325 whp on RC440's with room to spare... I have a set in the FS forum... PM'ed