My friend is a little special and doesn't know how to make threads.

Can injectors be doubled up on the secondary side?

 

Yes, I've logged over 3,000 miles so far on someones FD. I'll be doing some dyno tuning next week hopefully...

 

Any extra resistors or anything needed?

 

I use 3ohm resistors.

 

Page 80 of the FC Edit manual (Datalogit software) covers this. It gives a poorly written explanation for how to calculate how much wattage the injector drivers are seeing so you don't overheat them.

I have detailed more fully how to do this calculation here: https://www.rx7club.com/power-fc-forum-47/power-fc-injector-resistors-849993/

Basically it is a two-step calculation using two different resistance values:

"V=I*R (Ohm's law. in this case voltage equals the injector's current multiplied by resistance of the injector itself (including external resistor))
P=I^2*R (Joule's law. In this case, the injector's power/wattage equals the injector's current squared, then multiplied by the resistance of the injector driver transistor)"

some of that information is given by the FC Edit instructions, like the resistance of the injector driver transistor. it's admittedly technical, but is detailed further in that thread. The FC Edit instructions actually discuss adding two high impedence injectors out of a series 5 car, resistors are not discussed directly.

 

Check the resistance of everything hooked up, and as long as the total resistance of each channel is above around 6.5 ohms it should be fine. If it's lower you should add resistors.

 

Forgot to also add that yes, the injectors have to be of high OR higher resistance. Off the top of my head I believe mine are 13.5-13.8.