I upgraded my secondary injectors to 800cc. Fuel correction is at 10% at 11.5 afr. Stock primaries are still 550. Would putting 800s In The Primary spot help my top end? I got a extra set laying around. Would be nice if it would help. To make this clear I have 800cc secondaries and want to know if adding 800s to my primaries also will help my top end from starving for fuel. Thanks ryan

 

This is a good question, I'm running gsl se injectors in my secondaries which were flow tested at 760cc (rated at 680cc in fb fuel system), my primaries are 550 cc .

I'm running in the 12's for afr with an rtek 1.7 and walbro 255 lph at all boost levels up to 12+ psi.

I have yet to rewire the fuel pump, that will be getting done soon.


I was thinking of running all 720s (gsl se injectors) , and upgrading to the rtek 1.8 which is designed for all 720s , my current is designed for 550/720 , for the record my 550s tested at 620cc.

Tests were done at 2.25 bar (32.5 psi) which is relatively low , had the injectors cleaned and flow tested by injector rehab, I haven't checked my fuel pressure or voltage at fuel pump, will ve rewiring soon , wish me luck.

 

if you are running out of fuel near the end of the RPM range, upgrading the primaries would help with this but you will need to remove fuel from the maps below your injector staging point. primaries are used from 0 RPMs until wherever you close the throttle so upping the primary injector size adds fuel to ALL RPM ranges. if you have a stock ECU with a piggyback fuel modifier then the 800's might create flodding issues due to the lacking ability to change the amount of fuel injected during cranking.