how are the secondaries activated, is it map based? and at what point do they come on?

 

the secondary injectors come on when the primary injectors reach 40% injector duty. Then the secondary injectors fire until they also reach 40%, then both primary and secondary fire at the same time.

 

what if you're fooling it w/ a fuel computer like the s-afc. i have 1200cc secondaries, and i want to lean it out down low w/ the s-afc. i was wondering if this would cause the secondaries to not come on in time since the engine thinks it's getting less airflow than it really is.

 

I am pretty sure it's staged like the turbos:

Primaries only

OR

Primary + Secondary

I don't think there are any times that only the secondaries are firing.

The RPM at which the injector staging change occurs is variable, so any attempts to get the car to run smoothly with the primary:secondary ratio changed and an RPM-based adjustment map (S-AFC, PMC, etc) will be unsuccessful. There have been several attempts by smart and determined people to make this work. The conclusion is that it doesn't yield good drivability.

-Max