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could someone please help me with injector flow rate conversion, i need to convert lb per hour or cc per minute to miliseconds per gram

1 lb/hr ~ 0.126grams/sec = 7936 ms/g ~ 10.76cc/min (assuming gasoline weighs 737kg/m3 per kingflow spreadsheet)

is there an easy way to change the injector size in the bin, e.g. changing from 220cc to 240cc without changing the tune as performance is not the goal?

also if for example if an injector runs 300cc at 3.0 bar does this make it 350cc at 3.5 bar

i know these are probably dumb noob questions but i need to learn the very basics and work too much to spend a lot of time toolin around with my projects

You can adjust injrate by the % difference for cc changes. Eg 220 to 240 would be (220/240)*current injrate. (thats not much of a change though, you'd probably want to go a fair bit larger injectors to make the change worth while and for headroom).

i guess it depends on the reason behind the change, if its purely because you have a brand new (or cleaned) set of 240cc's and they are replacing old dodgy 220cc's then its fair enough, but if like antus says your going for more capacity etc then you probably really need to go bigger to make it worth the effort.

that said 10% change in injector size can be the difference between big enough or not

if an injector runs 300cc at 3.0 bar does this make it 350cc at 3.5 bar

No it will much less of a change, this spreadsheet does the calc .. https://pcmhacking.net/forums/viewtopi ... 675#p21675

But if you want to manually calc it, use.. New Flow Rate = Current Flow rate * sqrt(NewPressure/CurrentPressure)