So me and my cheap self decided to try and decap an extra set of OEM fuel injectors (look up decapping from a Subie forum if you're not familiar).
Seeing I'm shooting for north of 250HP, and the needed injectors for that power can be calculated as:
injector size in lbs./hr. = (Max. HP x BSFC) / (number of injectors x duty cycle)
BSFC = 0.55-0.65 (forced induction)
HP = 250HP
# of injectors = 4
max duty cycle = .80 (80%)
so we have:
injector size in lbs./hr. = (250 x .65) / (4 x .8)
= 50.78 lbs/hr
and that in cc is:
50.78lbs/hr = 533.2 cc/min
our OEM is rated at 280cc/min and given the fact that WRX owners can modify their injectors by "decapping" they achieve 850ish cc from the 440cc, so assuming you can essentially double, our 280cc would become 560ish cc, which is perfect. Or so I thought.
Fuel injector caps are a restrictor and help change the spray pattern, but it looks like our OEM injectors in fact don't have such caps. The "cap" is actually the entire piece and once removed you can dissemble the whole fuel injector. try and clean that out of a cylinder head... yea no thanks.
Here's my experience decapping these injectors.
Seeing I'm shooting for north of 250HP, and the needed injectors for that power can be calculated as:
injector size in lbs./hr. = (Max. HP x BSFC) / (number of injectors x duty cycle)
BSFC = 0.55-0.65 (forced induction)
HP = 250HP
# of injectors = 4
max duty cycle = .80 (80%)
so we have:
injector size in lbs./hr. = (250 x .65) / (4 x .8)
= 50.78 lbs/hr
and that in cc is:
50.78lbs/hr = 533.2 cc/min
our OEM is rated at 280cc/min and given the fact that WRX owners can modify their injectors by "decapping" they achieve 850ish cc from the 440cc, so assuming you can essentially double, our 280cc would become 560ish cc, which is perfect. Or so I thought.
Fuel injector caps are a restrictor and help change the spray pattern, but it looks like our OEM injectors in fact don't have such caps. The "cap" is actually the entire piece and once removed you can dissemble the whole fuel injector. try and clean that out of a cylinder head... yea no thanks.
Here's my experience decapping these injectors.