lt1 obd1 injector size change

[criticalx]

lt1 obd1 changing injector to ford 42lb green tops..what all i need to chane in tune? and how to change ve tables for the new injectors?

[steveo]

ve tables never have to be compensated for larger injectors.

just change your injector constant and injector offset vs. voltage table, if you can find that data.

those are some friggn giant injectors for an LT1, what exactly are you building?

[criticalx]

well with out changing ve tables ve table at wot is maxed.. 99.6 on 85 90 95 100 tables
just building a heads and cam for now.. getting the 42 for good deal from a racing friend and they leave room to grow

[steveo]

do you have a data sheet for the injectors?

is this a 1992-1993 speed density build or...

bigger isn't always better when it comes to injectors, just warning you.

[steveo]

anyway, volumetric efficiency is an airflow mapping, and changing your injectors alters fueling, not airflow. changing your injector size shouldn't mess with your VE much at all if your injector constant and offsets are right.

[criticalx]

its a speed density tune.. not getting injector till thursday.. but im going bigger on my build over the winter.

[criticalx]

cam only my injector was maxed and now i added ported heads... its bad lean.. what do i need to change for fueling?

[Fast355]

cam only my injector was maxed and now i added ported heads... its bad lean.. what do i need to change for fueling?

Smaller injectors!!! 42s are good for over 550 hp maybe as much as 600 depending on BSFC. Only way you would need that would be FI or dry N20. 30-32s would be much more appropriate for a hot LT1.

[criticalx]

ok.. on injector but what makes injector flow more per set up

[steveo]

you're missing some basic principles here. injectors flow a certain amount per time of injector opening. it doesn't matter if it's a civic or a bigblock chevy, a 42lb/hr injector is going to flow roughly 42lb/hr at its rated fuel pressure (which is also important, and that's why i asked if you had the datasheet for them).

so what exactly did you set your injector constant to?

[criticalx]

you're missing some basic principles here. injectors flow a certain amount per time of injector opening. it doesn't matter if it's a civic or a bigblock chevy, a 42lb/hr injector is going to flow roughly 42lb/hr at its rated fuel pressure (which is also important, and that's why i asked if you had the datasheet for them).

so what exactly did you set your injector constant to?

I don't have injectors yet.. my injectors are set stock now.

[steveo]

so you still have time to back out and get something reasonable, then?

[criticalx]

so you still have time to back out and get something reasonable, then?

yes. But won't 30 be over % 80 to start with

[steveo]

no. 30lb injectors are huge for any 350 LT1 with a head/cam build.

[criticalx]

So 30 will work? Where best place to get them