i used to be good at math in school, but my lack of practice makes me come here for my answer. i have a z6 revving to roughly 7500rpm shooting for 400hp with about 25psi. what injectors do i need? 800cc be good?

 

you'll be fine with 800's... Idk if I've ever seen an 800cc squirt before though. Look at JFK78. 750's got him 440hp at 28 pounds on a mustang dyno with a y8.

 

Yeah I think 750cc's are plenty. Precision makes high imp 660cc's that are supposed to be good to like 440 at the crank and their only $260 shipped from LSD and they'll be easier to to work with at idle.

 

in my head 800's seem like overkill. it was just a number i threw out there

 

http://rceng.com/technical.aspx?User...NzZLLU8jFtjded

 

i tried that a fwe days ago and came up with 800cc. that seemed a bit overkill to me, but i guess its better to have too much than not enough. idle smoothness isnt a huge concern as long as it will idle

 

It all depends really on how high a duty cycle you want to run...

 

from what i have read injectors shouldnt be run above 80% duty cycle so thats what i set it on the calculator. i dont mind running 800cc injectors, i will deal with a not so nice idle. i just dont want to be pushing the injectors to the limit all the time or not have enough for the power level.

 

I came up with 720cc's for 400hp @ 80% duty cycle and 0.55 BSFC, and 680cc @ 85% duty cycle. I usually go with 0.55 for BSFC on forced induction setups, RC's site lists to use 0.60 though which seems a bit higher than normal (most n/a honda's run at 0.45 bsfc) but would land you around the 800cc mark.

 

i did 60 cause thats what they reccomend. i think i will just get 800cc injectors then i dont have to worry about it