Injector recommendation

[mitchy]

i'm about to buy a plenum with a top feed fuel rail, and i'm wondering if its worth selling my ~500km old 740cc side feeds, and getting some smaller top feed injectors?

my max power figure is probably 400ish rwhp with this turbo, so 740's are pretty big.. would it be beneficial to downgrade to say a 550/600cc injector?

and what top feed injectors are available for a RB25, running an R33 GTS-T PFC...
loom/plugs doesn't matter as i have a custom loom at the moment, but i dont want to use resistor packs or whatever they are...

[cplagz]

Resistor packs are required for low-Z injectors. If you are going to a top feed rail you will need top feed injectors obviously. What size bungs are the rail and plenum? 11mm or 14mm? Also, I'm assuming this is for a 6cyl.

Using a BSFC calculator, to have a maximum of 80% duty cycle at 500hp@flywheel, you need injectors between 660 - 710cc. If you want to push the duty cycle higher, obviously you can go lower with the injectors. e.g. 90% duty = 580 - 630cc.

Low-z injectors have shorter opening times then High-z, hence why they are good for large injectors to be able to control idle.

So my answer is no, I wouldn't downgrade. I'd be looking for some similar injectors.